| /* |
| * NETLINK Kernel-user communication protocol. |
| * |
| * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk> |
| * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> |
| * Patrick McHardy <kaber@trash.net> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith |
| * added netlink_proto_exit |
| * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br> |
| * use nlk_sk, as sk->protinfo is on a diet 8) |
| * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org> |
| * - inc module use count of module that owns |
| * the kernel socket in case userspace opens |
| * socket of same protocol |
| * - remove all module support, since netlink is |
| * mandatory if CONFIG_NET=y these days |
| */ |
| |
| #include <linux/module.h> |
| |
| #include <linux/capability.h> |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/signal.h> |
| #include <linux/sched.h> |
| #include <linux/errno.h> |
| #include <linux/string.h> |
| #include <linux/stat.h> |
| #include <linux/socket.h> |
| #include <linux/un.h> |
| #include <linux/fcntl.h> |
| #include <linux/termios.h> |
| #include <linux/sockios.h> |
| #include <linux/net.h> |
| #include <linux/fs.h> |
| #include <linux/slab.h> |
| #include <asm/uaccess.h> |
| #include <linux/skbuff.h> |
| #include <linux/netdevice.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/notifier.h> |
| #include <linux/security.h> |
| #include <linux/jhash.h> |
| #include <linux/jiffies.h> |
| #include <linux/random.h> |
| #include <linux/bitops.h> |
| #include <linux/mm.h> |
| #include <linux/types.h> |
| #include <linux/audit.h> |
| #include <linux/mutex.h> |
| #include <linux/vmalloc.h> |
| #include <linux/if_arp.h> |
| #include <linux/rhashtable.h> |
| #include <asm/cacheflush.h> |
| #include <linux/hash.h> |
| #include <linux/genetlink.h> |
| |
| #include <net/net_namespace.h> |
| #include <net/sock.h> |
| #include <net/scm.h> |
| #include <net/netlink.h> |
| |
| #include "af_netlink.h" |
| |
| struct listeners { |
| struct rcu_head rcu; |
| unsigned long masks[0]; |
| }; |
| |
| /* state bits */ |
| #define NETLINK_S_CONGESTED 0x0 |
| |
| /* flags */ |
| #define NETLINK_F_KERNEL_SOCKET 0x1 |
| #define NETLINK_F_RECV_PKTINFO 0x2 |
| #define NETLINK_F_BROADCAST_SEND_ERROR 0x4 |
| #define NETLINK_F_RECV_NO_ENOBUFS 0x8 |
| #define NETLINK_F_LISTEN_ALL_NSID 0x10 |
| #define NETLINK_F_CAP_ACK 0x20 |
| |
| static inline int netlink_is_kernel(struct sock *sk) |
| { |
| return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET; |
| } |
| |
| struct netlink_table *nl_table __read_mostly; |
| EXPORT_SYMBOL_GPL(nl_table); |
| |
| static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); |
| |
| static int netlink_dump(struct sock *sk); |
| static void netlink_skb_destructor(struct sk_buff *skb); |
| |
| /* nl_table locking explained: |
| * Lookup and traversal are protected with an RCU read-side lock. Insertion |
| * and removal are protected with per bucket lock while using RCU list |
| * modification primitives and may run in parallel to RCU protected lookups. |
| * Destruction of the Netlink socket may only occur *after* nl_table_lock has |
| * been acquired * either during or after the socket has been removed from |
| * the list and after an RCU grace period. |
| */ |
| DEFINE_RWLOCK(nl_table_lock); |
| EXPORT_SYMBOL_GPL(nl_table_lock); |
| static atomic_t nl_table_users = ATOMIC_INIT(0); |
| |
| #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock)); |
| |
| static ATOMIC_NOTIFIER_HEAD(netlink_chain); |
| |
| static DEFINE_SPINLOCK(netlink_tap_lock); |
| static struct list_head netlink_tap_all __read_mostly; |
| |
| static const struct rhashtable_params netlink_rhashtable_params; |
| |
| static inline u32 netlink_group_mask(u32 group) |
| { |
| return group ? 1 << (group - 1) : 0; |
| } |
| |
| static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb, |
| gfp_t gfp_mask) |
| { |
| unsigned int len = skb_end_offset(skb); |
| struct sk_buff *new; |
| |
| new = alloc_skb(len, gfp_mask); |
| if (new == NULL) |
| return NULL; |
| |
| NETLINK_CB(new).portid = NETLINK_CB(skb).portid; |
| NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group; |
| NETLINK_CB(new).creds = NETLINK_CB(skb).creds; |
| |
| memcpy(skb_put(new, len), skb->data, len); |
| return new; |
| } |
| |
| int netlink_add_tap(struct netlink_tap *nt) |
| { |
| if (unlikely(nt->dev->type != ARPHRD_NETLINK)) |
| return -EINVAL; |
| |
| spin_lock(&netlink_tap_lock); |
| list_add_rcu(&nt->list, &netlink_tap_all); |
| spin_unlock(&netlink_tap_lock); |
| |
| __module_get(nt->module); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(netlink_add_tap); |
| |
| static int __netlink_remove_tap(struct netlink_tap *nt) |
| { |
| bool found = false; |
| struct netlink_tap *tmp; |
| |
| spin_lock(&netlink_tap_lock); |
| |
| list_for_each_entry(tmp, &netlink_tap_all, list) { |
| if (nt == tmp) { |
| list_del_rcu(&nt->list); |
| found = true; |
| goto out; |
| } |
| } |
| |
| pr_warn("__netlink_remove_tap: %p not found\n", nt); |
| out: |
| spin_unlock(&netlink_tap_lock); |
| |
| if (found) |
| module_put(nt->module); |
| |
| return found ? 0 : -ENODEV; |
| } |
| |
| int netlink_remove_tap(struct netlink_tap *nt) |
| { |
| int ret; |
| |
| ret = __netlink_remove_tap(nt); |
| synchronize_net(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(netlink_remove_tap); |
| |
| static bool netlink_filter_tap(const struct sk_buff *skb) |
| { |
| struct sock *sk = skb->sk; |
| |
| /* We take the more conservative approach and |
| * whitelist socket protocols that may pass. |
| */ |
| switch (sk->sk_protocol) { |
| case NETLINK_ROUTE: |
| case NETLINK_USERSOCK: |
| case NETLINK_SOCK_DIAG: |
| case NETLINK_NFLOG: |
| case NETLINK_XFRM: |
| case NETLINK_FIB_LOOKUP: |
| case NETLINK_NETFILTER: |
| case NETLINK_GENERIC: |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static int __netlink_deliver_tap_skb(struct sk_buff *skb, |
| struct net_device *dev) |
| { |
| struct sk_buff *nskb; |
| struct sock *sk = skb->sk; |
| int ret = -ENOMEM; |
| |
| dev_hold(dev); |
| |
| if (netlink_skb_is_mmaped(skb) || is_vmalloc_addr(skb->head)) |
| nskb = netlink_to_full_skb(skb, GFP_ATOMIC); |
| else |
| nskb = skb_clone(skb, GFP_ATOMIC); |
| if (nskb) { |
| nskb->dev = dev; |
| nskb->protocol = htons((u16) sk->sk_protocol); |
| nskb->pkt_type = netlink_is_kernel(sk) ? |
| PACKET_KERNEL : PACKET_USER; |
| skb_reset_network_header(nskb); |
| ret = dev_queue_xmit(nskb); |
| if (unlikely(ret > 0)) |
| ret = net_xmit_errno(ret); |
| } |
| |
| dev_put(dev); |
| return ret; |
| } |
| |
| static void __netlink_deliver_tap(struct sk_buff *skb) |
| { |
| int ret; |
| struct netlink_tap *tmp; |
| |
| if (!netlink_filter_tap(skb)) |
| return; |
| |
| list_for_each_entry_rcu(tmp, &netlink_tap_all, list) { |
| ret = __netlink_deliver_tap_skb(skb, tmp->dev); |
| if (unlikely(ret)) |
| break; |
| } |
| } |
| |
| static void netlink_deliver_tap(struct sk_buff *skb) |
| { |
| rcu_read_lock(); |
| |
| if (unlikely(!list_empty(&netlink_tap_all))) |
| __netlink_deliver_tap(skb); |
| |
| rcu_read_unlock(); |
| } |
| |
| static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src, |
| struct sk_buff *skb) |
| { |
| if (!(netlink_is_kernel(dst) && netlink_is_kernel(src))) |
| netlink_deliver_tap(skb); |
| } |
| |
| static void netlink_overrun(struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) { |
| if (!test_and_set_bit(NETLINK_S_CONGESTED, |
| &nlk_sk(sk)->state)) { |
| sk->sk_err = ENOBUFS; |
| sk->sk_error_report(sk); |
| } |
| } |
| atomic_inc(&sk->sk_drops); |
| } |
| |
| static void netlink_rcv_wake(struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| if (skb_queue_empty(&sk->sk_receive_queue)) |
| clear_bit(NETLINK_S_CONGESTED, &nlk->state); |
| if (!test_bit(NETLINK_S_CONGESTED, &nlk->state)) |
| wake_up_interruptible(&nlk->wait); |
| } |
| |
| #ifdef CONFIG_NETLINK_MMAP |
| static bool netlink_rx_is_mmaped(struct sock *sk) |
| { |
| return nlk_sk(sk)->rx_ring.pg_vec != NULL; |
| } |
| |
| static bool netlink_tx_is_mmaped(struct sock *sk) |
| { |
| return nlk_sk(sk)->tx_ring.pg_vec != NULL; |
| } |
| |
| static __pure struct page *pgvec_to_page(const void *addr) |
| { |
| if (is_vmalloc_addr(addr)) |
| return vmalloc_to_page(addr); |
| else |
| return virt_to_page(addr); |
| } |
| |
| static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < len; i++) { |
| if (pg_vec[i] != NULL) { |
| if (is_vmalloc_addr(pg_vec[i])) |
| vfree(pg_vec[i]); |
| else |
| free_pages((unsigned long)pg_vec[i], order); |
| } |
| } |
| kfree(pg_vec); |
| } |
| |
| static void *alloc_one_pg_vec_page(unsigned long order) |
| { |
| void *buffer; |
| gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO | |
| __GFP_NOWARN | __GFP_NORETRY; |
| |
| buffer = (void *)__get_free_pages(gfp_flags, order); |
| if (buffer != NULL) |
| return buffer; |
| |
| buffer = vzalloc((1 << order) * PAGE_SIZE); |
| if (buffer != NULL) |
| return buffer; |
| |
| gfp_flags &= ~__GFP_NORETRY; |
| return (void *)__get_free_pages(gfp_flags, order); |
| } |
| |
| static void **alloc_pg_vec(struct netlink_sock *nlk, |
| struct nl_mmap_req *req, unsigned int order) |
| { |
| unsigned int block_nr = req->nm_block_nr; |
| unsigned int i; |
| void **pg_vec; |
| |
| pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL); |
| if (pg_vec == NULL) |
| return NULL; |
| |
| for (i = 0; i < block_nr; i++) { |
| pg_vec[i] = alloc_one_pg_vec_page(order); |
| if (pg_vec[i] == NULL) |
| goto err1; |
| } |
| |
| return pg_vec; |
| err1: |
| free_pg_vec(pg_vec, order, block_nr); |
| return NULL; |
| } |
| |
| |
| static void |
| __netlink_set_ring(struct sock *sk, struct nl_mmap_req *req, bool tx_ring, void **pg_vec, |
| unsigned int order) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct sk_buff_head *queue; |
| struct netlink_ring *ring; |
| |
| queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue; |
| ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring; |
| |
| spin_lock_bh(&queue->lock); |
| |
| ring->frame_max = req->nm_frame_nr - 1; |
| ring->head = 0; |
| ring->frame_size = req->nm_frame_size; |
| ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE; |
| |
| swap(ring->pg_vec_len, req->nm_block_nr); |
| swap(ring->pg_vec_order, order); |
| swap(ring->pg_vec, pg_vec); |
| |
| __skb_queue_purge(queue); |
| spin_unlock_bh(&queue->lock); |
| |
| WARN_ON(atomic_read(&nlk->mapped)); |
| |
| if (pg_vec) |
| free_pg_vec(pg_vec, order, req->nm_block_nr); |
| } |
| |
| static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req, |
| bool tx_ring) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct netlink_ring *ring; |
| void **pg_vec = NULL; |
| unsigned int order = 0; |
| |
| ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring; |
| |
| if (atomic_read(&nlk->mapped)) |
| return -EBUSY; |
| if (atomic_read(&ring->pending)) |
| return -EBUSY; |
| |
| if (req->nm_block_nr) { |
| if (ring->pg_vec != NULL) |
| return -EBUSY; |
| |
| if ((int)req->nm_block_size <= 0) |
| return -EINVAL; |
| if (!PAGE_ALIGNED(req->nm_block_size)) |
| return -EINVAL; |
| if (req->nm_frame_size < NL_MMAP_HDRLEN) |
| return -EINVAL; |
| if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT)) |
| return -EINVAL; |
| |
| ring->frames_per_block = req->nm_block_size / |
| req->nm_frame_size; |
| if (ring->frames_per_block == 0) |
| return -EINVAL; |
| if (ring->frames_per_block * req->nm_block_nr != |
| req->nm_frame_nr) |
| return -EINVAL; |
| |
| order = get_order(req->nm_block_size); |
| pg_vec = alloc_pg_vec(nlk, req, order); |
| if (pg_vec == NULL) |
| return -ENOMEM; |
| } else { |
| if (req->nm_frame_nr) |
| return -EINVAL; |
| } |
| |
| mutex_lock(&nlk->pg_vec_lock); |
| if (atomic_read(&nlk->mapped) == 0) { |
| __netlink_set_ring(sk, req, tx_ring, pg_vec, order); |
| mutex_unlock(&nlk->pg_vec_lock); |
| return 0; |
| } |
| |
| mutex_unlock(&nlk->pg_vec_lock); |
| |
| if (pg_vec) |
| free_pg_vec(pg_vec, order, req->nm_block_nr); |
| |
| return -EBUSY; |
| } |
| |
| static void netlink_mm_open(struct vm_area_struct *vma) |
| { |
| struct file *file = vma->vm_file; |
| struct socket *sock = file->private_data; |
| struct sock *sk = sock->sk; |
| |
| if (sk) |
| atomic_inc(&nlk_sk(sk)->mapped); |
| } |
| |
| static void netlink_mm_close(struct vm_area_struct *vma) |
| { |
| struct file *file = vma->vm_file; |
| struct socket *sock = file->private_data; |
| struct sock *sk = sock->sk; |
| |
| if (sk) |
| atomic_dec(&nlk_sk(sk)->mapped); |
| } |
| |
| static const struct vm_operations_struct netlink_mmap_ops = { |
| .open = netlink_mm_open, |
| .close = netlink_mm_close, |
| }; |
| |
| static int netlink_mmap(struct file *file, struct socket *sock, |
| struct vm_area_struct *vma) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct netlink_ring *ring; |
| unsigned long start, size, expected; |
| unsigned int i; |
| int err = -EINVAL; |
| |
| if (vma->vm_pgoff) |
| return -EINVAL; |
| |
| mutex_lock(&nlk->pg_vec_lock); |
| |
| expected = 0; |
| for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) { |
| if (ring->pg_vec == NULL) |
| continue; |
| expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE; |
| } |
| |
| if (expected == 0) |
| goto out; |
| |
| size = vma->vm_end - vma->vm_start; |
| if (size != expected) |
| goto out; |
| |
| start = vma->vm_start; |
| for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) { |
| if (ring->pg_vec == NULL) |
| continue; |
| |
| for (i = 0; i < ring->pg_vec_len; i++) { |
| struct page *page; |
| void *kaddr = ring->pg_vec[i]; |
| unsigned int pg_num; |
| |
| for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) { |
| page = pgvec_to_page(kaddr); |
| err = vm_insert_page(vma, start, page); |
| if (err < 0) |
| goto out; |
| start += PAGE_SIZE; |
| kaddr += PAGE_SIZE; |
| } |
| } |
| } |
| |
| atomic_inc(&nlk->mapped); |
| vma->vm_ops = &netlink_mmap_ops; |
| err = 0; |
| out: |
| mutex_unlock(&nlk->pg_vec_lock); |
| return err; |
| } |
| |
| static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr, unsigned int nm_len) |
| { |
| #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1 |
| struct page *p_start, *p_end; |
| |
| /* First page is flushed through netlink_{get,set}_status */ |
| p_start = pgvec_to_page(hdr + PAGE_SIZE); |
| p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + nm_len - 1); |
| while (p_start <= p_end) { |
| flush_dcache_page(p_start); |
| p_start++; |
| } |
| #endif |
| } |
| |
| static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr) |
| { |
| smp_rmb(); |
| flush_dcache_page(pgvec_to_page(hdr)); |
| return hdr->nm_status; |
| } |
| |
| static void netlink_set_status(struct nl_mmap_hdr *hdr, |
| enum nl_mmap_status status) |
| { |
| smp_mb(); |
| hdr->nm_status = status; |
| flush_dcache_page(pgvec_to_page(hdr)); |
| } |
| |
| static struct nl_mmap_hdr * |
| __netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos) |
| { |
| unsigned int pg_vec_pos, frame_off; |
| |
| pg_vec_pos = pos / ring->frames_per_block; |
| frame_off = pos % ring->frames_per_block; |
| |
| return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size); |
| } |
| |
| static struct nl_mmap_hdr * |
| netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos, |
| enum nl_mmap_status status) |
| { |
| struct nl_mmap_hdr *hdr; |
| |
| hdr = __netlink_lookup_frame(ring, pos); |
| if (netlink_get_status(hdr) != status) |
| return NULL; |
| |
| return hdr; |
| } |
| |
| static struct nl_mmap_hdr * |
| netlink_current_frame(const struct netlink_ring *ring, |
| enum nl_mmap_status status) |
| { |
| return netlink_lookup_frame(ring, ring->head, status); |
| } |
| |
| static void netlink_increment_head(struct netlink_ring *ring) |
| { |
| ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0; |
| } |
| |
| static void netlink_forward_ring(struct netlink_ring *ring) |
| { |
| unsigned int head = ring->head; |
| const struct nl_mmap_hdr *hdr; |
| |
| do { |
| hdr = __netlink_lookup_frame(ring, ring->head); |
| if (hdr->nm_status == NL_MMAP_STATUS_UNUSED) |
| break; |
| if (hdr->nm_status != NL_MMAP_STATUS_SKIP) |
| break; |
| netlink_increment_head(ring); |
| } while (ring->head != head); |
| } |
| |
| static bool netlink_has_valid_frame(struct netlink_ring *ring) |
| { |
| unsigned int head = ring->head, pos = head; |
| const struct nl_mmap_hdr *hdr; |
| |
| do { |
| hdr = __netlink_lookup_frame(ring, pos); |
| if (hdr->nm_status == NL_MMAP_STATUS_VALID) |
| return true; |
| pos = pos != 0 ? pos - 1 : ring->frame_max; |
| } while (pos != head); |
| |
| return false; |
| } |
| |
| static bool netlink_dump_space(struct netlink_sock *nlk) |
| { |
| struct netlink_ring *ring = &nlk->rx_ring; |
| struct nl_mmap_hdr *hdr; |
| unsigned int n; |
| |
| hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED); |
| if (hdr == NULL) |
| return false; |
| |
| n = ring->head + ring->frame_max / 2; |
| if (n > ring->frame_max) |
| n -= ring->frame_max; |
| |
| hdr = __netlink_lookup_frame(ring, n); |
| |
| return hdr->nm_status == NL_MMAP_STATUS_UNUSED; |
| } |
| |
| static unsigned int netlink_poll(struct file *file, struct socket *sock, |
| poll_table *wait) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| unsigned int mask; |
| int err; |
| |
| if (nlk->rx_ring.pg_vec != NULL) { |
| /* Memory mapped sockets don't call recvmsg(), so flow control |
| * for dumps is performed here. A dump is allowed to continue |
| * if at least half the ring is unused. |
| */ |
| while (nlk->cb_running && netlink_dump_space(nlk)) { |
| err = netlink_dump(sk); |
| if (err < 0) { |
| sk->sk_err = -err; |
| sk->sk_error_report(sk); |
| break; |
| } |
| } |
| netlink_rcv_wake(sk); |
| } |
| |
| mask = datagram_poll(file, sock, wait); |
| |
| /* We could already have received frames in the normal receive |
| * queue, that will show up as NL_MMAP_STATUS_COPY in the ring, |
| * so if mask contains pollin/etc already, there's no point |
| * walking the ring. |
| */ |
| if ((mask & (POLLIN | POLLRDNORM)) != (POLLIN | POLLRDNORM)) { |
| spin_lock_bh(&sk->sk_receive_queue.lock); |
| if (nlk->rx_ring.pg_vec) { |
| if (netlink_has_valid_frame(&nlk->rx_ring)) |
| mask |= POLLIN | POLLRDNORM; |
| } |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| } |
| |
| spin_lock_bh(&sk->sk_write_queue.lock); |
| if (nlk->tx_ring.pg_vec) { |
| if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED)) |
| mask |= POLLOUT | POLLWRNORM; |
| } |
| spin_unlock_bh(&sk->sk_write_queue.lock); |
| |
| return mask; |
| } |
| |
| static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb) |
| { |
| return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN); |
| } |
| |
| static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk, |
| struct netlink_ring *ring, |
| struct nl_mmap_hdr *hdr) |
| { |
| unsigned int size; |
| void *data; |
| |
| size = ring->frame_size - NL_MMAP_HDRLEN; |
| data = (void *)hdr + NL_MMAP_HDRLEN; |
| |
| skb->head = data; |
| skb->data = data; |
| skb_reset_tail_pointer(skb); |
| skb->end = skb->tail + size; |
| skb->len = 0; |
| |
| skb->destructor = netlink_skb_destructor; |
| NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED; |
| NETLINK_CB(skb).sk = sk; |
| } |
| |
| static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg, |
| u32 dst_portid, u32 dst_group, |
| struct scm_cookie *scm) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct netlink_ring *ring; |
| struct nl_mmap_hdr *hdr; |
| struct sk_buff *skb; |
| unsigned int maxlen; |
| int err = 0, len = 0; |
| |
| mutex_lock(&nlk->pg_vec_lock); |
| |
| ring = &nlk->tx_ring; |
| maxlen = ring->frame_size - NL_MMAP_HDRLEN; |
| |
| do { |
| unsigned int nm_len; |
| |
| hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID); |
| if (hdr == NULL) { |
| if (!(msg->msg_flags & MSG_DONTWAIT) && |
| atomic_read(&nlk->tx_ring.pending)) |
| schedule(); |
| continue; |
| } |
| |
| nm_len = ACCESS_ONCE(hdr->nm_len); |
| if (nm_len > maxlen) { |
| err = -EINVAL; |
| goto out; |
| } |
| |
| netlink_frame_flush_dcache(hdr, nm_len); |
| |
| skb = alloc_skb(nm_len, GFP_KERNEL); |
| if (skb == NULL) { |
| err = -ENOBUFS; |
| goto out; |
| } |
| __skb_put(skb, nm_len); |
| memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, nm_len); |
| netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED); |
| |
| netlink_increment_head(ring); |
| |
| NETLINK_CB(skb).portid = nlk->portid; |
| NETLINK_CB(skb).dst_group = dst_group; |
| NETLINK_CB(skb).creds = scm->creds; |
| |
| err = security_netlink_send(sk, skb); |
| if (err) { |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| if (unlikely(dst_group)) { |
| atomic_inc(&skb->users); |
| netlink_broadcast(sk, skb, dst_portid, dst_group, |
| GFP_KERNEL); |
| } |
| err = netlink_unicast(sk, skb, dst_portid, |
| msg->msg_flags & MSG_DONTWAIT); |
| if (err < 0) |
| goto out; |
| len += err; |
| |
| } while (hdr != NULL || |
| (!(msg->msg_flags & MSG_DONTWAIT) && |
| atomic_read(&nlk->tx_ring.pending))); |
| |
| if (len > 0) |
| err = len; |
| out: |
| mutex_unlock(&nlk->pg_vec_lock); |
| return err; |
| } |
| |
| static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb) |
| { |
| struct nl_mmap_hdr *hdr; |
| |
| hdr = netlink_mmap_hdr(skb); |
| hdr->nm_len = skb->len; |
| hdr->nm_group = NETLINK_CB(skb).dst_group; |
| hdr->nm_pid = NETLINK_CB(skb).creds.pid; |
| hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid); |
| hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid); |
| netlink_frame_flush_dcache(hdr, hdr->nm_len); |
| netlink_set_status(hdr, NL_MMAP_STATUS_VALID); |
| |
| NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED; |
| kfree_skb(skb); |
| } |
| |
| static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct netlink_ring *ring = &nlk->rx_ring; |
| struct nl_mmap_hdr *hdr; |
| |
| spin_lock_bh(&sk->sk_receive_queue.lock); |
| hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED); |
| if (hdr == NULL) { |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| kfree_skb(skb); |
| netlink_overrun(sk); |
| return; |
| } |
| netlink_increment_head(ring); |
| __skb_queue_tail(&sk->sk_receive_queue, skb); |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| |
| hdr->nm_len = skb->len; |
| hdr->nm_group = NETLINK_CB(skb).dst_group; |
| hdr->nm_pid = NETLINK_CB(skb).creds.pid; |
| hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid); |
| hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid); |
| netlink_set_status(hdr, NL_MMAP_STATUS_COPY); |
| } |
| |
| #else /* CONFIG_NETLINK_MMAP */ |
| #define netlink_rx_is_mmaped(sk) false |
| #define netlink_tx_is_mmaped(sk) false |
| #define netlink_mmap sock_no_mmap |
| #define netlink_poll datagram_poll |
| #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, scm) 0 |
| #endif /* CONFIG_NETLINK_MMAP */ |
| |
| static void netlink_skb_destructor(struct sk_buff *skb) |
| { |
| #ifdef CONFIG_NETLINK_MMAP |
| struct nl_mmap_hdr *hdr; |
| struct netlink_ring *ring; |
| struct sock *sk; |
| |
| /* If a packet from the kernel to userspace was freed because of an |
| * error without being delivered to userspace, the kernel must reset |
| * the status. In the direction userspace to kernel, the status is |
| * always reset here after the packet was processed and freed. |
| */ |
| if (netlink_skb_is_mmaped(skb)) { |
| hdr = netlink_mmap_hdr(skb); |
| sk = NETLINK_CB(skb).sk; |
| |
| if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) { |
| netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED); |
| ring = &nlk_sk(sk)->tx_ring; |
| } else { |
| if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) { |
| hdr->nm_len = 0; |
| netlink_set_status(hdr, NL_MMAP_STATUS_VALID); |
| } |
| ring = &nlk_sk(sk)->rx_ring; |
| } |
| |
| WARN_ON(atomic_read(&ring->pending) == 0); |
| atomic_dec(&ring->pending); |
| sock_put(sk); |
| |
| skb->head = NULL; |
| } |
| #endif |
| if (is_vmalloc_addr(skb->head)) { |
| if (!skb->cloned || |
| !atomic_dec_return(&(skb_shinfo(skb)->dataref))) |
| vfree(skb->head); |
| |
| skb->head = NULL; |
| } |
| if (skb->sk != NULL) |
| sock_rfree(skb); |
| } |
| |
| static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) |
| { |
| WARN_ON(skb->sk != NULL); |
| skb->sk = sk; |
| skb->destructor = netlink_skb_destructor; |
| atomic_add(skb->truesize, &sk->sk_rmem_alloc); |
| sk_mem_charge(sk, skb->truesize); |
| } |
| |
| static void netlink_sock_destruct(struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| if (nlk->cb_running) { |
| if (nlk->cb.done) |
| nlk->cb.done(&nlk->cb); |
| |
| module_put(nlk->cb.module); |
| kfree_skb(nlk->cb.skb); |
| } |
| |
| skb_queue_purge(&sk->sk_receive_queue); |
| #ifdef CONFIG_NETLINK_MMAP |
| if (1) { |
| struct nl_mmap_req req; |
| |
| memset(&req, 0, sizeof(req)); |
| if (nlk->rx_ring.pg_vec) |
| __netlink_set_ring(sk, &req, false, NULL, 0); |
| memset(&req, 0, sizeof(req)); |
| if (nlk->tx_ring.pg_vec) |
| __netlink_set_ring(sk, &req, true, NULL, 0); |
| } |
| #endif /* CONFIG_NETLINK_MMAP */ |
| |
| if (!sock_flag(sk, SOCK_DEAD)) { |
| printk(KERN_ERR "Freeing alive netlink socket %p\n", sk); |
| return; |
| } |
| |
| WARN_ON(atomic_read(&sk->sk_rmem_alloc)); |
| WARN_ON(atomic_read(&sk->sk_wmem_alloc)); |
| WARN_ON(nlk_sk(sk)->groups); |
| } |
| |
| /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on |
| * SMP. Look, when several writers sleep and reader wakes them up, all but one |
| * immediately hit write lock and grab all the cpus. Exclusive sleep solves |
| * this, _but_ remember, it adds useless work on UP machines. |
| */ |
| |
| void netlink_table_grab(void) |
| __acquires(nl_table_lock) |
| { |
| might_sleep(); |
| |
| write_lock_irq(&nl_table_lock); |
| |
| if (atomic_read(&nl_table_users)) { |
| DECLARE_WAITQUEUE(wait, current); |
| |
| add_wait_queue_exclusive(&nl_table_wait, &wait); |
| for (;;) { |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| if (atomic_read(&nl_table_users) == 0) |
| break; |
| write_unlock_irq(&nl_table_lock); |
| schedule(); |
| write_lock_irq(&nl_table_lock); |
| } |
| |
| __set_current_state(TASK_RUNNING); |
| remove_wait_queue(&nl_table_wait, &wait); |
| } |
| } |
| |
| void netlink_table_ungrab(void) |
| __releases(nl_table_lock) |
| { |
| write_unlock_irq(&nl_table_lock); |
| wake_up(&nl_table_wait); |
| } |
| |
| static inline void |
| netlink_lock_table(void) |
| { |
| /* read_lock() synchronizes us to netlink_table_grab */ |
| |
| read_lock(&nl_table_lock); |
| atomic_inc(&nl_table_users); |
| read_unlock(&nl_table_lock); |
| } |
| |
| static inline void |
| netlink_unlock_table(void) |
| { |
| if (atomic_dec_and_test(&nl_table_users)) |
| wake_up(&nl_table_wait); |
| } |
| |
| struct netlink_compare_arg |
| { |
| possible_net_t pnet; |
| u32 portid; |
| }; |
| |
| /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */ |
| #define netlink_compare_arg_len \ |
| (offsetof(struct netlink_compare_arg, portid) + sizeof(u32)) |
| |
| static inline int netlink_compare(struct rhashtable_compare_arg *arg, |
| const void *ptr) |
| { |
| const struct netlink_compare_arg *x = arg->key; |
| const struct netlink_sock *nlk = ptr; |
| |
| return nlk->portid != x->portid || |
| !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet)); |
| } |
| |
| static void netlink_compare_arg_init(struct netlink_compare_arg *arg, |
| struct net *net, u32 portid) |
| { |
| memset(arg, 0, sizeof(*arg)); |
| write_pnet(&arg->pnet, net); |
| arg->portid = portid; |
| } |
| |
| static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid, |
| struct net *net) |
| { |
| struct netlink_compare_arg arg; |
| |
| netlink_compare_arg_init(&arg, net, portid); |
| return rhashtable_lookup_fast(&table->hash, &arg, |
| netlink_rhashtable_params); |
| } |
| |
| static int __netlink_insert(struct netlink_table *table, struct sock *sk) |
| { |
| struct netlink_compare_arg arg; |
| |
| netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid); |
| return rhashtable_lookup_insert_key(&table->hash, &arg, |
| &nlk_sk(sk)->node, |
| netlink_rhashtable_params); |
| } |
| |
| static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid) |
| { |
| struct netlink_table *table = &nl_table[protocol]; |
| struct sock *sk; |
| |
| rcu_read_lock(); |
| sk = __netlink_lookup(table, portid, net); |
| if (sk) |
| sock_hold(sk); |
| rcu_read_unlock(); |
| |
| return sk; |
| } |
| |
| static const struct proto_ops netlink_ops; |
| |
| static void |
| netlink_update_listeners(struct sock *sk) |
| { |
| struct netlink_table *tbl = &nl_table[sk->sk_protocol]; |
| unsigned long mask; |
| unsigned int i; |
| struct listeners *listeners; |
| |
| listeners = nl_deref_protected(tbl->listeners); |
| if (!listeners) |
| return; |
| |
| for (i = 0; i < NLGRPLONGS(tbl->groups); i++) { |
| mask = 0; |
| sk_for_each_bound(sk, &tbl->mc_list) { |
| if (i < NLGRPLONGS(nlk_sk(sk)->ngroups)) |
| mask |= nlk_sk(sk)->groups[i]; |
| } |
| listeners->masks[i] = mask; |
| } |
| /* this function is only called with the netlink table "grabbed", which |
| * makes sure updates are visible before bind or setsockopt return. */ |
| } |
| |
| static int netlink_insert(struct sock *sk, u32 portid) |
| { |
| struct netlink_table *table = &nl_table[sk->sk_protocol]; |
| int err; |
| |
| lock_sock(sk); |
| |
| err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY; |
| if (nlk_sk(sk)->bound) |
| goto err; |
| |
| err = -ENOMEM; |
| if (BITS_PER_LONG > 32 && |
| unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX)) |
| goto err; |
| |
| nlk_sk(sk)->portid = portid; |
| sock_hold(sk); |
| |
| err = __netlink_insert(table, sk); |
| if (err) { |
| /* In case the hashtable backend returns with -EBUSY |
| * from here, it must not escape to the caller. |
| */ |
| if (unlikely(err == -EBUSY)) |
| err = -EOVERFLOW; |
| if (err == -EEXIST) |
| err = -EADDRINUSE; |
| sock_put(sk); |
| goto err; |
| } |
| |
| /* We need to ensure that the socket is hashed and visible. */ |
| smp_wmb(); |
| nlk_sk(sk)->bound = portid; |
| |
| err: |
| release_sock(sk); |
| return err; |
| } |
| |
| static void netlink_remove(struct sock *sk) |
| { |
| struct netlink_table *table; |
| |
| table = &nl_table[sk->sk_protocol]; |
| if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node, |
| netlink_rhashtable_params)) { |
| WARN_ON(atomic_read(&sk->sk_refcnt) == 1); |
| __sock_put(sk); |
| } |
| |
| netlink_table_grab(); |
| if (nlk_sk(sk)->subscriptions) { |
| __sk_del_bind_node(sk); |
| netlink_update_listeners(sk); |
| } |
| if (sk->sk_protocol == NETLINK_GENERIC) |
| atomic_inc(&genl_sk_destructing_cnt); |
| netlink_table_ungrab(); |
| } |
| |
| static struct proto netlink_proto = { |
| .name = "NETLINK", |
| .owner = THIS_MODULE, |
| .obj_size = sizeof(struct netlink_sock), |
| }; |
| |
| static int __netlink_create(struct net *net, struct socket *sock, |
| struct mutex *cb_mutex, int protocol, |
| int kern) |
| { |
| struct sock *sk; |
| struct netlink_sock *nlk; |
| |
| sock->ops = &netlink_ops; |
| |
| sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern); |
| if (!sk) |
| return -ENOMEM; |
| |
| sock_init_data(sock, sk); |
| |
| nlk = nlk_sk(sk); |
| if (cb_mutex) { |
| nlk->cb_mutex = cb_mutex; |
| } else { |
| nlk->cb_mutex = &nlk->cb_def_mutex; |
| mutex_init(nlk->cb_mutex); |
| } |
| init_waitqueue_head(&nlk->wait); |
| #ifdef CONFIG_NETLINK_MMAP |
| mutex_init(&nlk->pg_vec_lock); |
| #endif |
| |
| sk->sk_destruct = netlink_sock_destruct; |
| sk->sk_protocol = protocol; |
| return 0; |
| } |
| |
| static int netlink_create(struct net *net, struct socket *sock, int protocol, |
| int kern) |
| { |
| struct module *module = NULL; |
| struct mutex *cb_mutex; |
| struct netlink_sock *nlk; |
| int (*bind)(struct net *net, int group); |
| void (*unbind)(struct net *net, int group); |
| int err = 0; |
| |
| sock->state = SS_UNCONNECTED; |
| |
| if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM) |
| return -ESOCKTNOSUPPORT; |
| |
| if (protocol < 0 || protocol >= MAX_LINKS) |
| return -EPROTONOSUPPORT; |
| |
| netlink_lock_table(); |
| #ifdef CONFIG_MODULES |
| if (!nl_table[protocol].registered) { |
| netlink_unlock_table(); |
| request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); |
| netlink_lock_table(); |
| } |
| #endif |
| if (nl_table[protocol].registered && |
| try_module_get(nl_table[protocol].module)) |
| module = nl_table[protocol].module; |
| else |
| err = -EPROTONOSUPPORT; |
| cb_mutex = nl_table[protocol].cb_mutex; |
| bind = nl_table[protocol].bind; |
| unbind = nl_table[protocol].unbind; |
| netlink_unlock_table(); |
| |
| if (err < 0) |
| goto out; |
| |
| err = __netlink_create(net, sock, cb_mutex, protocol, kern); |
| if (err < 0) |
| goto out_module; |
| |
| local_bh_disable(); |
| sock_prot_inuse_add(net, &netlink_proto, 1); |
| local_bh_enable(); |
| |
| nlk = nlk_sk(sock->sk); |
| nlk->module = module; |
| nlk->netlink_bind = bind; |
| nlk->netlink_unbind = unbind; |
| out: |
| return err; |
| |
| out_module: |
| module_put(module); |
| goto out; |
| } |
| |
| static void deferred_put_nlk_sk(struct rcu_head *head) |
| { |
| struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu); |
| |
| sock_put(&nlk->sk); |
| } |
| |
| static int netlink_release(struct socket *sock) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk; |
| |
| if (!sk) |
| return 0; |
| |
| netlink_remove(sk); |
| sock_orphan(sk); |
| nlk = nlk_sk(sk); |
| |
| /* |
| * OK. Socket is unlinked, any packets that arrive now |
| * will be purged. |
| */ |
| |
| /* must not acquire netlink_table_lock in any way again before unbind |
| * and notifying genetlink is done as otherwise it might deadlock |
| */ |
| if (nlk->netlink_unbind) { |
| int i; |
| |
| for (i = 0; i < nlk->ngroups; i++) |
| if (test_bit(i, nlk->groups)) |
| nlk->netlink_unbind(sock_net(sk), i + 1); |
| } |
| if (sk->sk_protocol == NETLINK_GENERIC && |
| atomic_dec_return(&genl_sk_destructing_cnt) == 0) |
| wake_up(&genl_sk_destructing_waitq); |
| |
| sock->sk = NULL; |
| wake_up_interruptible_all(&nlk->wait); |
| |
| skb_queue_purge(&sk->sk_write_queue); |
| |
| if (nlk->portid) { |
| struct netlink_notify n = { |
| .net = sock_net(sk), |
| .protocol = sk->sk_protocol, |
| .portid = nlk->portid, |
| }; |
| atomic_notifier_call_chain(&netlink_chain, |
| NETLINK_URELEASE, &n); |
| } |
| |
| module_put(nlk->module); |
| |
| if (netlink_is_kernel(sk)) { |
| netlink_table_grab(); |
| BUG_ON(nl_table[sk->sk_protocol].registered == 0); |
| if (--nl_table[sk->sk_protocol].registered == 0) { |
| struct listeners *old; |
| |
| old = nl_deref_protected(nl_table[sk->sk_protocol].listeners); |
| RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL); |
| kfree_rcu(old, rcu); |
| nl_table[sk->sk_protocol].module = NULL; |
| nl_table[sk->sk_protocol].bind = NULL; |
| nl_table[sk->sk_protocol].unbind = NULL; |
| nl_table[sk->sk_protocol].flags = 0; |
| nl_table[sk->sk_protocol].registered = 0; |
| } |
| netlink_table_ungrab(); |
| } |
| |
| kfree(nlk->groups); |
| nlk->groups = NULL; |
| |
| local_bh_disable(); |
| sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); |
| local_bh_enable(); |
| call_rcu(&nlk->rcu, deferred_put_nlk_sk); |
| return 0; |
| } |
| |
| static int netlink_autobind(struct socket *sock) |
| { |
| struct sock *sk = sock->sk; |
| struct net *net = sock_net(sk); |
| struct netlink_table *table = &nl_table[sk->sk_protocol]; |
| s32 portid = task_tgid_vnr(current); |
| int err; |
| s32 rover = -4096; |
| bool ok; |
| |
| retry: |
| cond_resched(); |
| rcu_read_lock(); |
| ok = !__netlink_lookup(table, portid, net); |
| rcu_read_unlock(); |
| if (!ok) { |
| /* Bind collision, search negative portid values. */ |
| if (rover == -4096) |
| /* rover will be in range [S32_MIN, -4097] */ |
| rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN); |
| else if (rover >= -4096) |
| rover = -4097; |
| portid = rover--; |
| goto retry; |
| } |
| |
| err = netlink_insert(sk, portid); |
| if (err == -EADDRINUSE) |
| goto retry; |
| |
| /* If 2 threads race to autobind, that is fine. */ |
| if (err == -EBUSY) |
| err = 0; |
| |
| return err; |
| } |
| |
| /** |
| * __netlink_ns_capable - General netlink message capability test |
| * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace. |
| * @user_ns: The user namespace of the capability to use |
| * @cap: The capability to use |
| * |
| * Test to see if the opener of the socket we received the message |
| * from had when the netlink socket was created and the sender of the |
| * message has has the capability @cap in the user namespace @user_ns. |
| */ |
| bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, |
| struct user_namespace *user_ns, int cap) |
| { |
| return ((nsp->flags & NETLINK_SKB_DST) || |
| file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) && |
| ns_capable(user_ns, cap); |
| } |
| EXPORT_SYMBOL(__netlink_ns_capable); |
| |
| /** |
| * netlink_ns_capable - General netlink message capability test |
| * @skb: socket buffer holding a netlink command from userspace |
| * @user_ns: The user namespace of the capability to use |
| * @cap: The capability to use |
| * |
| * Test to see if the opener of the socket we received the message |
| * from had when the netlink socket was created and the sender of the |
| * message has has the capability @cap in the user namespace @user_ns. |
| */ |
| bool netlink_ns_capable(const struct sk_buff *skb, |
| struct user_namespace *user_ns, int cap) |
| { |
| return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap); |
| } |
| EXPORT_SYMBOL(netlink_ns_capable); |
| |
| /** |
| * netlink_capable - Netlink global message capability test |
| * @skb: socket buffer holding a netlink command from userspace |
| * @cap: The capability to use |
| * |
| * Test to see if the opener of the socket we received the message |
| * from had when the netlink socket was created and the sender of the |
| * message has has the capability @cap in all user namespaces. |
| */ |
| bool netlink_capable(const struct sk_buff *skb, int cap) |
| { |
| return netlink_ns_capable(skb, &init_user_ns, cap); |
| } |
| EXPORT_SYMBOL(netlink_capable); |
| |
| /** |
| * netlink_net_capable - Netlink network namespace message capability test |
| * @skb: socket buffer holding a netlink command from userspace |
| * @cap: The capability to use |
| * |
| * Test to see if the opener of the socket we received the message |
| * from had when the netlink socket was created and the sender of the |
| * message has has the capability @cap over the network namespace of |
| * the socket we received the message from. |
| */ |
| bool netlink_net_capable(const struct sk_buff *skb, int cap) |
| { |
| return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap); |
| } |
| EXPORT_SYMBOL(netlink_net_capable); |
| |
| static inline int netlink_allowed(const struct socket *sock, unsigned int flag) |
| { |
| return (nl_table[sock->sk->sk_protocol].flags & flag) || |
| ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN); |
| } |
| |
| static void |
| netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| if (nlk->subscriptions && !subscriptions) |
| __sk_del_bind_node(sk); |
| else if (!nlk->subscriptions && subscriptions) |
| sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); |
| nlk->subscriptions = subscriptions; |
| } |
| |
| static int netlink_realloc_groups(struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| unsigned int groups; |
| unsigned long *new_groups; |
| int err = 0; |
| |
| netlink_table_grab(); |
| |
| groups = nl_table[sk->sk_protocol].groups; |
| if (!nl_table[sk->sk_protocol].registered) { |
| err = -ENOENT; |
| goto out_unlock; |
| } |
| |
| if (nlk->ngroups >= groups) |
| goto out_unlock; |
| |
| new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC); |
| if (new_groups == NULL) { |
| err = -ENOMEM; |
| goto out_unlock; |
| } |
| memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0, |
| NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups)); |
| |
| nlk->groups = new_groups; |
| nlk->ngroups = groups; |
| out_unlock: |
| netlink_table_ungrab(); |
| return err; |
| } |
| |
| static void netlink_undo_bind(int group, long unsigned int groups, |
| struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| int undo; |
| |
| if (!nlk->netlink_unbind) |
| return; |
| |
| for (undo = 0; undo < group; undo++) |
| if (test_bit(undo, &groups)) |
| nlk->netlink_unbind(sock_net(sk), undo + 1); |
| } |
| |
| static int netlink_bind(struct socket *sock, struct sockaddr *addr, |
| int addr_len) |
| { |
| struct sock *sk = sock->sk; |
| struct net *net = sock_net(sk); |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; |
| int err; |
| long unsigned int groups = nladdr->nl_groups; |
| bool bound; |
| |
| if (addr_len < sizeof(struct sockaddr_nl)) |
| return -EINVAL; |
| |
| if (nladdr->nl_family != AF_NETLINK) |
| return -EINVAL; |
| |
| /* Only superuser is allowed to listen multicasts */ |
| if (groups) { |
| if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) |
| return -EPERM; |
| err = netlink_realloc_groups(sk); |
| if (err) |
| return err; |
| } |
| |
| bound = nlk->bound; |
| if (bound) { |
| /* Ensure nlk->portid is up-to-date. */ |
| smp_rmb(); |
| |
| if (nladdr->nl_pid != nlk->portid) |
| return -EINVAL; |
| } |
| |
| if (nlk->netlink_bind && groups) { |
| int group; |
| |
| for (group = 0; group < nlk->ngroups; group++) { |
| if (!test_bit(group, &groups)) |
| continue; |
| err = nlk->netlink_bind(net, group + 1); |
| if (!err) |
| continue; |
| netlink_undo_bind(group, groups, sk); |
| return err; |
| } |
| } |
| |
| /* No need for barriers here as we return to user-space without |
| * using any of the bound attributes. |
| */ |
| if (!bound) { |
| err = nladdr->nl_pid ? |
| netlink_insert(sk, nladdr->nl_pid) : |
| netlink_autobind(sock); |
| if (err) { |
| netlink_undo_bind(nlk->ngroups, groups, sk); |
| return err; |
| } |
| } |
| |
| if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) |
| return 0; |
| |
| netlink_table_grab(); |
| netlink_update_subscriptions(sk, nlk->subscriptions + |
| hweight32(groups) - |
| hweight32(nlk->groups[0])); |
| nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups; |
| netlink_update_listeners(sk); |
| netlink_table_ungrab(); |
| |
| return 0; |
| } |
| |
| static int netlink_connect(struct socket *sock, struct sockaddr *addr, |
| int alen, int flags) |
| { |
| int err = 0; |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr; |
| |
| if (alen < sizeof(addr->sa_family)) |
| return -EINVAL; |
| |
| if (addr->sa_family == AF_UNSPEC) { |
| sk->sk_state = NETLINK_UNCONNECTED; |
| nlk->dst_portid = 0; |
| nlk->dst_group = 0; |
| return 0; |
| } |
| if (addr->sa_family != AF_NETLINK) |
| return -EINVAL; |
| |
| if ((nladdr->nl_groups || nladdr->nl_pid) && |
| !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) |
| return -EPERM; |
| |
| /* No need for barriers here as we return to user-space without |
| * using any of the bound attributes. |
| */ |
| if (!nlk->bound) |
| err = netlink_autobind(sock); |
| |
| if (err == 0) { |
| sk->sk_state = NETLINK_CONNECTED; |
| nlk->dst_portid = nladdr->nl_pid; |
| nlk->dst_group = ffs(nladdr->nl_groups); |
| } |
| |
| return err; |
| } |
| |
| static int netlink_getname(struct socket *sock, struct sockaddr *addr, |
| int *addr_len, int peer) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr); |
| |
| nladdr->nl_family = AF_NETLINK; |
| nladdr->nl_pad = 0; |
| *addr_len = sizeof(*nladdr); |
| |
| if (peer) { |
| nladdr->nl_pid = nlk->dst_portid; |
| nladdr->nl_groups = netlink_group_mask(nlk->dst_group); |
| } else { |
| nladdr->nl_pid = nlk->portid; |
| nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0; |
| } |
| return 0; |
| } |
| |
| static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) |
| { |
| struct sock *sock; |
| struct netlink_sock *nlk; |
| |
| sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid); |
| if (!sock) |
| return ERR_PTR(-ECONNREFUSED); |
| |
| /* Don't bother queuing skb if kernel socket has no input function */ |
| nlk = nlk_sk(sock); |
| if (sock->sk_state == NETLINK_CONNECTED && |
| nlk->dst_portid != nlk_sk(ssk)->portid) { |
| sock_put(sock); |
| return ERR_PTR(-ECONNREFUSED); |
| } |
| return sock; |
| } |
| |
| struct sock *netlink_getsockbyfilp(struct file *filp) |
| { |
| struct inode *inode = file_inode(filp); |
| struct sock *sock; |
| |
| if (!S_ISSOCK(inode->i_mode)) |
| return ERR_PTR(-ENOTSOCK); |
| |
| sock = SOCKET_I(inode)->sk; |
| if (sock->sk_family != AF_NETLINK) |
| return ERR_PTR(-EINVAL); |
| |
| sock_hold(sock); |
| return sock; |
| } |
| |
| static struct sk_buff *netlink_alloc_large_skb(unsigned int size, |
| int broadcast) |
| { |
| struct sk_buff *skb; |
| void *data; |
| |
| if (size <= NLMSG_GOODSIZE || broadcast) |
| return alloc_skb(size, GFP_KERNEL); |
| |
| size = SKB_DATA_ALIGN(size) + |
| SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| |
| data = vmalloc(size); |
| if (data == NULL) |
| return NULL; |
| |
| skb = __build_skb(data, size); |
| if (skb == NULL) |
| vfree(data); |
| else |
| skb->destructor = netlink_skb_destructor; |
| |
| return skb; |
| } |
| |
| /* |
| * Attach a skb to a netlink socket. |
| * The caller must hold a reference to the destination socket. On error, the |
| * reference is dropped. The skb is not send to the destination, just all |
| * all error checks are performed and memory in the queue is reserved. |
| * Return values: |
| * < 0: error. skb freed, reference to sock dropped. |
| * 0: continue |
| * 1: repeat lookup - reference dropped while waiting for socket memory. |
| */ |
| int netlink_attachskb(struct sock *sk, struct sk_buff *skb, |
| long *timeo, struct sock *ssk) |
| { |
| struct netlink_sock *nlk; |
| |
| nlk = nlk_sk(sk); |
| |
| if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || |
| test_bit(NETLINK_S_CONGESTED, &nlk->state)) && |
| !netlink_skb_is_mmaped(skb)) { |
| DECLARE_WAITQUEUE(wait, current); |
| if (!*timeo) { |
| if (!ssk || netlink_is_kernel(ssk)) |
| netlink_overrun(sk); |
| sock_put(sk); |
| kfree_skb(skb); |
| return -EAGAIN; |
| } |
| |
| __set_current_state(TASK_INTERRUPTIBLE); |
| add_wait_queue(&nlk->wait, &wait); |
| |
| if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf || |
| test_bit(NETLINK_S_CONGESTED, &nlk->state)) && |
| !sock_flag(sk, SOCK_DEAD)) |
| *timeo = schedule_timeout(*timeo); |
| |
| __set_current_state(TASK_RUNNING); |
| remove_wait_queue(&nlk->wait, &wait); |
| sock_put(sk); |
| |
| if (signal_pending(current)) { |
| kfree_skb(skb); |
| return sock_intr_errno(*timeo); |
| } |
| return 1; |
| } |
| netlink_skb_set_owner_r(skb, sk); |
| return 0; |
| } |
| |
| static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) |
| { |
| int len = skb->len; |
| |
| netlink_deliver_tap(skb); |
| |
| #ifdef CONFIG_NETLINK_MMAP |
| if (netlink_skb_is_mmaped(skb)) |
| netlink_queue_mmaped_skb(sk, skb); |
| else if (netlink_rx_is_mmaped(sk)) |
| netlink_ring_set_copied(sk, skb); |
| else |
| #endif /* CONFIG_NETLINK_MMAP */ |
| skb_queue_tail(&sk->sk_receive_queue, skb); |
| sk->sk_data_ready(sk); |
| return len; |
| } |
| |
| int netlink_sendskb(struct sock *sk, struct sk_buff *skb) |
| { |
| int len = __netlink_sendskb(sk, skb); |
| |
| sock_put(sk); |
| return len; |
| } |
| |
| void netlink_detachskb(struct sock *sk, struct sk_buff *skb) |
| { |
| kfree_skb(skb); |
| sock_put(sk); |
| } |
| |
| static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation) |
| { |
| int delta; |
| |
| WARN_ON(skb->sk != NULL); |
| if (netlink_skb_is_mmaped(skb)) |
| return skb; |
| |
| delta = skb->end - skb->tail; |
| if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize) |
| return skb; |
| |
| if (skb_shared(skb)) { |
| struct sk_buff *nskb = skb_clone(skb, allocation); |
| if (!nskb) |
| return skb; |
| consume_skb(skb); |
| skb = nskb; |
| } |
| |
| if (!pskb_expand_head(skb, 0, -delta, allocation)) |
| skb->truesize -= delta; |
| |
| return skb; |
| } |
| |
| static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, |
| struct sock *ssk) |
| { |
| int ret; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| ret = -ECONNREFUSED; |
| if (nlk->netlink_rcv != NULL) { |
| ret = skb->len; |
| netlink_skb_set_owner_r(skb, sk); |
| NETLINK_CB(skb).sk = ssk; |
| netlink_deliver_tap_kernel(sk, ssk, skb); |
| nlk->netlink_rcv(skb); |
| consume_skb(skb); |
| } else { |
| kfree_skb(skb); |
| } |
| sock_put(sk); |
| return ret; |
| } |
| |
| int netlink_unicast(struct sock *ssk, struct sk_buff *skb, |
| u32 portid, int nonblock) |
| { |
| struct sock *sk; |
| int err; |
| long timeo; |
| |
| skb = netlink_trim(skb, gfp_any()); |
| |
| timeo = sock_sndtimeo(ssk, nonblock); |
| retry: |
| sk = netlink_getsockbyportid(ssk, portid); |
| if (IS_ERR(sk)) { |
| kfree_skb(skb); |
| return PTR_ERR(sk); |
| } |
| if (netlink_is_kernel(sk)) |
| return netlink_unicast_kernel(sk, skb, ssk); |
| |
| if (sk_filter(sk, skb)) { |
| err = skb->len; |
| kfree_skb(skb); |
| sock_put(sk); |
| return err; |
| } |
| |
| err = netlink_attachskb(sk, skb, &timeo, ssk); |
| if (err == 1) |
| goto retry; |
| if (err) |
| return err; |
| |
| return netlink_sendskb(sk, skb); |
| } |
| EXPORT_SYMBOL(netlink_unicast); |
| |
| struct sk_buff *__netlink_alloc_skb(struct sock *ssk, unsigned int size, |
| unsigned int ldiff, u32 dst_portid, |
| gfp_t gfp_mask) |
| { |
| #ifdef CONFIG_NETLINK_MMAP |
| unsigned int maxlen, linear_size; |
| struct sock *sk = NULL; |
| struct sk_buff *skb; |
| struct netlink_ring *ring; |
| struct nl_mmap_hdr *hdr; |
| |
| sk = netlink_getsockbyportid(ssk, dst_portid); |
| if (IS_ERR(sk)) |
| goto out; |
| |
| ring = &nlk_sk(sk)->rx_ring; |
| /* fast-path without atomic ops for common case: non-mmaped receiver */ |
| if (ring->pg_vec == NULL) |
| goto out_put; |
| |
| /* We need to account the full linear size needed as a ring |
| * slot cannot have non-linear parts. |
| */ |
| linear_size = size + ldiff; |
| if (ring->frame_size - NL_MMAP_HDRLEN < linear_size) |
| goto out_put; |
| |
| skb = alloc_skb_head(gfp_mask); |
| if (skb == NULL) |
| goto err1; |
| |
| spin_lock_bh(&sk->sk_receive_queue.lock); |
| /* check again under lock */ |
| if (ring->pg_vec == NULL) |
| goto out_free; |
| |
| /* check again under lock */ |
| maxlen = ring->frame_size - NL_MMAP_HDRLEN; |
| if (maxlen < linear_size) |
| goto out_free; |
| |
| netlink_forward_ring(ring); |
| hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED); |
| if (hdr == NULL) |
| goto err2; |
| |
| netlink_ring_setup_skb(skb, sk, ring, hdr); |
| netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED); |
| atomic_inc(&ring->pending); |
| netlink_increment_head(ring); |
| |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| return skb; |
| |
| err2: |
| kfree_skb(skb); |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| netlink_overrun(sk); |
| err1: |
| sock_put(sk); |
| return NULL; |
| |
| out_free: |
| kfree_skb(skb); |
| spin_unlock_bh(&sk->sk_receive_queue.lock); |
| out_put: |
| sock_put(sk); |
| out: |
| #endif |
| return alloc_skb(size, gfp_mask); |
| } |
| EXPORT_SYMBOL_GPL(__netlink_alloc_skb); |
| |
| int netlink_has_listeners(struct sock *sk, unsigned int group) |
| { |
| int res = 0; |
| struct listeners *listeners; |
| |
| BUG_ON(!netlink_is_kernel(sk)); |
| |
| rcu_read_lock(); |
| listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners); |
| |
| if (listeners && group - 1 < nl_table[sk->sk_protocol].groups) |
| res = test_bit(group - 1, listeners->masks); |
| |
| rcu_read_unlock(); |
| |
| return res; |
| } |
| EXPORT_SYMBOL_GPL(netlink_has_listeners); |
| |
| static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| |
| if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf && |
| !test_bit(NETLINK_S_CONGESTED, &nlk->state)) { |
| netlink_skb_set_owner_r(skb, sk); |
| __netlink_sendskb(sk, skb); |
| return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1); |
| } |
| return -1; |
| } |
| |
| struct netlink_broadcast_data { |
| struct sock *exclude_sk; |
| struct net *net; |
| u32 portid; |
| u32 group; |
| int failure; |
| int delivery_failure; |
| int congested; |
| int delivered; |
| gfp_t allocation; |
| struct sk_buff *skb, *skb2; |
| int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data); |
| void *tx_data; |
| }; |
| |
| static void do_one_broadcast(struct sock *sk, |
| struct netlink_broadcast_data *p) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| int val; |
| |
| if (p->exclude_sk == sk) |
| return; |
| |
| if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || |
| !test_bit(p->group - 1, nlk->groups)) |
| return; |
| |
| if (!net_eq(sock_net(sk), p->net)) { |
| if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID)) |
| return; |
| |
| if (!peernet_has_id(sock_net(sk), p->net)) |
| return; |
| |
| if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns, |
| CAP_NET_BROADCAST)) |
| return; |
| } |
| |
| if (p->failure) { |
| netlink_overrun(sk); |
| return; |
| } |
| |
| sock_hold(sk); |
| if (p->skb2 == NULL) { |
| if (skb_shared(p->skb)) { |
| p->skb2 = skb_clone(p->skb, p->allocation); |
| } else { |
| p->skb2 = skb_get(p->skb); |
| /* |
| * skb ownership may have been set when |
| * delivered to a previous socket. |
| */ |
| skb_orphan(p->skb2); |
| } |
| } |
| if (p->skb2 == NULL) { |
| netlink_overrun(sk); |
| /* Clone failed. Notify ALL listeners. */ |
| p->failure = 1; |
| if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) |
| p->delivery_failure = 1; |
| goto out; |
| } |
| if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) { |
| kfree_skb(p->skb2); |
| p->skb2 = NULL; |
| goto out; |
| } |
| if (sk_filter(sk, p->skb2)) { |
| kfree_skb(p->skb2); |
| p->skb2 = NULL; |
| goto out; |
| } |
| NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net); |
| NETLINK_CB(p->skb2).nsid_is_set = true; |
| val = netlink_broadcast_deliver(sk, p->skb2); |
| if (val < 0) { |
| netlink_overrun(sk); |
| if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR) |
| p->delivery_failure = 1; |
| } else { |
| p->congested |= val; |
| p->delivered = 1; |
| p->skb2 = NULL; |
| } |
| out: |
| sock_put(sk); |
| } |
| |
| int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid, |
| u32 group, gfp_t allocation, |
| int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), |
| void *filter_data) |
| { |
| struct net *net = sock_net(ssk); |
| struct netlink_broadcast_data info; |
| struct sock *sk; |
| |
| skb = netlink_trim(skb, allocation); |
| |
| info.exclude_sk = ssk; |
| info.net = net; |
| info.portid = portid; |
| info.group = group; |
| info.failure = 0; |
| info.delivery_failure = 0; |
| info.congested = 0; |
| info.delivered = 0; |
| info.allocation = allocation; |
| info.skb = skb; |
| info.skb2 = NULL; |
| info.tx_filter = filter; |
| info.tx_data = filter_data; |
| |
| /* While we sleep in clone, do not allow to change socket list */ |
| |
| netlink_lock_table(); |
| |
| sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) |
| do_one_broadcast(sk, &info); |
| |
| consume_skb(skb); |
| |
| netlink_unlock_table(); |
| |
| if (info.delivery_failure) { |
| kfree_skb(info.skb2); |
| return -ENOBUFS; |
| } |
| consume_skb(info.skb2); |
| |
| if (info.delivered) { |
| if (info.congested && gfpflags_allow_blocking(allocation)) |
| yield(); |
| return 0; |
| } |
| return -ESRCH; |
| } |
| EXPORT_SYMBOL(netlink_broadcast_filtered); |
| |
| int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, |
| u32 group, gfp_t allocation) |
| { |
| return netlink_broadcast_filtered(ssk, skb, portid, group, allocation, |
| NULL, NULL); |
| } |
| EXPORT_SYMBOL(netlink_broadcast); |
| |
| struct netlink_set_err_data { |
| struct sock *exclude_sk; |
| u32 portid; |
| u32 group; |
| int code; |
| }; |
| |
| static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| int ret = 0; |
| |
| if (sk == p->exclude_sk) |
| goto out; |
| |
| if (!net_eq(sock_net(sk), sock_net(p->exclude_sk))) |
| goto out; |
| |
| if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups || |
| !test_bit(p->group - 1, nlk->groups)) |
| goto out; |
| |
| if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) { |
| ret = 1; |
| goto out; |
| } |
| |
| sk->sk_err = p->code; |
| sk->sk_error_report(sk); |
| out: |
| return ret; |
| } |
| |
| /** |
| * netlink_set_err - report error to broadcast listeners |
| * @ssk: the kernel netlink socket, as returned by netlink_kernel_create() |
| * @portid: the PORTID of a process that we want to skip (if any) |
| * @group: the broadcast group that will notice the error |
| * @code: error code, must be negative (as usual in kernelspace) |
| * |
| * This function returns the number of broadcast listeners that have set the |
| * NETLINK_NO_ENOBUFS socket option. |
| */ |
| int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code) |
| { |
| struct netlink_set_err_data info; |
| struct sock *sk; |
| int ret = 0; |
| |
| info.exclude_sk = ssk; |
| info.portid = portid; |
| info.group = group; |
| /* sk->sk_err wants a positive error value */ |
| info.code = -code; |
| |
| read_lock(&nl_table_lock); |
| |
| sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) |
| ret += do_one_set_err(sk, &info); |
| |
| read_unlock(&nl_table_lock); |
| return ret; |
| } |
| EXPORT_SYMBOL(netlink_set_err); |
| |
| /* must be called with netlink table grabbed */ |
| static void netlink_update_socket_mc(struct netlink_sock *nlk, |
| unsigned int group, |
| int is_new) |
| { |
| int old, new = !!is_new, subscriptions; |
| |
| old = test_bit(group - 1, nlk->groups); |
| subscriptions = nlk->subscriptions - old + new; |
| if (new) |
| __set_bit(group - 1, nlk->groups); |
| else |
| __clear_bit(group - 1, nlk->groups); |
| netlink_update_subscriptions(&nlk->sk, subscriptions); |
| netlink_update_listeners(&nlk->sk); |
| } |
| |
| static int netlink_setsockopt(struct socket *sock, int level, int optname, |
| char __user *optval, unsigned int optlen) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| unsigned int val = 0; |
| int err; |
| |
| if (level != SOL_NETLINK) |
| return -ENOPROTOOPT; |
| |
| if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING && |
| optlen >= sizeof(int) && |
| get_user(val, (unsigned int __user *)optval)) |
| return -EFAULT; |
| |
| switch (optname) { |
| case NETLINK_PKTINFO: |
| if (val) |
| nlk->flags |= NETLINK_F_RECV_PKTINFO; |
| else |
| nlk->flags &= ~NETLINK_F_RECV_PKTINFO; |
| err = 0; |
| break; |
| case NETLINK_ADD_MEMBERSHIP: |
| case NETLINK_DROP_MEMBERSHIP: { |
| if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) |
| return -EPERM; |
| err = netlink_realloc_groups(sk); |
| if (err) |
| return err; |
| if (!val || val - 1 >= nlk->ngroups) |
| return -EINVAL; |
| if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) { |
| err = nlk->netlink_bind(sock_net(sk), val); |
| if (err) |
| return err; |
| } |
| netlink_table_grab(); |
| netlink_update_socket_mc(nlk, val, |
| optname == NETLINK_ADD_MEMBERSHIP); |
| netlink_table_ungrab(); |
| if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) |
| nlk->netlink_unbind(sock_net(sk), val); |
| |
| err = 0; |
| break; |
| } |
| case NETLINK_BROADCAST_ERROR: |
| if (val) |
| nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR; |
| else |
| nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR; |
| err = 0; |
| break; |
| case NETLINK_NO_ENOBUFS: |
| if (val) { |
| nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS; |
| clear_bit(NETLINK_S_CONGESTED, &nlk->state); |
| wake_up_interruptible(&nlk->wait); |
| } else { |
| nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS; |
| } |
| err = 0; |
| break; |
| #ifdef CONFIG_NETLINK_MMAP |
| case NETLINK_RX_RING: |
| case NETLINK_TX_RING: { |
| struct nl_mmap_req req; |
| |
| /* Rings might consume more memory than queue limits, require |
| * CAP_NET_ADMIN. |
| */ |
| if (!capable(CAP_NET_ADMIN)) |
| return -EPERM; |
| if (optlen < sizeof(req)) |
| return -EINVAL; |
| if (copy_from_user(&req, optval, sizeof(req))) |
| return -EFAULT; |
| err = netlink_set_ring(sk, &req, |
| optname == NETLINK_TX_RING); |
| break; |
| } |
| #endif /* CONFIG_NETLINK_MMAP */ |
| case NETLINK_LISTEN_ALL_NSID: |
| if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) |
| return -EPERM; |
| |
| if (val) |
| nlk->flags |= NETLINK_F_LISTEN_ALL_NSID; |
| else |
| nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID; |
| err = 0; |
| break; |
| case NETLINK_CAP_ACK: |
| if (val) |
| nlk->flags |= NETLINK_F_CAP_ACK; |
| else |
| nlk->flags &= ~NETLINK_F_CAP_ACK; |
| err = 0; |
| break; |
| default: |
| err = -ENOPROTOOPT; |
| } |
| return err; |
| } |
| |
| static int netlink_getsockopt(struct socket *sock, int level, int optname, |
| char __user *optval, int __user *optlen) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| int len, val, err; |
| |
| if (level != SOL_NETLINK) |
| return -ENOPROTOOPT; |
| |
| if (get_user(len, optlen)) |
| return -EFAULT; |
| if (len < 0) |
| return -EINVAL; |
| |
| switch (optname) { |
| case NETLINK_PKTINFO: |
| if (len < sizeof(int)) |
| return -EINVAL; |
| len = sizeof(int); |
| val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0; |
| if (put_user(len, optlen) || |
| put_user(val, optval)) |
| return -EFAULT; |
| err = 0; |
| break; |
| case NETLINK_BROADCAST_ERROR: |
| if (len < sizeof(int)) |
| return -EINVAL; |
| len = sizeof(int); |
| val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0; |
| if (put_user(len, optlen) || |
| put_user(val, optval)) |
| return -EFAULT; |
| err = 0; |
| break; |
| case NETLINK_NO_ENOBUFS: |
| if (len < sizeof(int)) |
| return -EINVAL; |
| len = sizeof(int); |
| val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0; |
| if (put_user(len, optlen) || |
| put_user(val, optval)) |
| return -EFAULT; |
| err = 0; |
| break; |
| case NETLINK_LIST_MEMBERSHIPS: { |
| int pos, idx, shift; |
| |
| err = 0; |
| netlink_lock_table(); |
| for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) { |
| if (len - pos < sizeof(u32)) |
| break; |
| |
| idx = pos / sizeof(unsigned long); |
| shift = (pos % sizeof(unsigned long)) * 8; |
| if (put_user((u32)(nlk->groups[idx] >> shift), |
| (u32 __user *)(optval + pos))) { |
| err = -EFAULT; |
| break; |
| } |
| } |
| if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen)) |
| err = -EFAULT; |
| netlink_unlock_table(); |
| break; |
| } |
| case NETLINK_CAP_ACK: |
| if (len < sizeof(int)) |
| return -EINVAL; |
| len = sizeof(int); |
| val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0; |
| if (put_user(len, optlen) || |
| put_user(val, optval)) |
| return -EFAULT; |
| err = 0; |
| break; |
| default: |
| err = -ENOPROTOOPT; |
| } |
| return err; |
| } |
| |
| static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb) |
| { |
| struct nl_pktinfo info; |
| |
| info.group = NETLINK_CB(skb).dst_group; |
| put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info); |
| } |
| |
| static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg, |
| struct sk_buff *skb) |
| { |
| if (!NETLINK_CB(skb).nsid_is_set) |
| return; |
| |
| put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int), |
| &NETLINK_CB(skb).nsid); |
| } |
| |
| static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) |
| { |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); |
| u32 dst_portid; |
| u32 dst_group; |
| struct sk_buff *skb; |
| int err; |
| struct scm_cookie scm; |
| u32 netlink_skb_flags = 0; |
| |
| if (msg->msg_flags&MSG_OOB) |
| return -EOPNOTSUPP; |
| |
| err = scm_send(sock, msg, &scm, true); |
| if (err < 0) |
| return err; |
| |
| if (msg->msg_namelen) { |
| err = -EINVAL; |
| if (addr->nl_family != AF_NETLINK) |
| goto out; |
| dst_portid = addr->nl_pid; |
| dst_group = ffs(addr->nl_groups); |
| err = -EPERM; |
| if ((dst_group || dst_portid) && |
| !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) |
| goto out; |
| netlink_skb_flags |= NETLINK_SKB_DST; |
| } else { |
| dst_portid = nlk->dst_portid; |
| dst_group = nlk->dst_group; |
| } |
| |
| if (!nlk->bound) { |
| err = netlink_autobind(sock); |
| if (err) |
| goto out; |
| } else { |
| /* Ensure nlk is hashed and visible. */ |
| smp_rmb(); |
| } |
| |
| /* It's a really convoluted way for userland to ask for mmaped |
| * sendmsg(), but that's what we've got... |
| */ |
| if (netlink_tx_is_mmaped(sk) && |
| iter_is_iovec(&msg->msg_iter) && |
| msg->msg_iter.nr_segs == 1 && |
| msg->msg_iter.iov->iov_base == NULL) { |
| err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, |
| &scm); |
| goto out; |
| } |
| |
| err = -EMSGSIZE; |
| if (len > sk->sk_sndbuf - 32) |
| goto out; |
| err = -ENOBUFS; |
| skb = netlink_alloc_large_skb(len, dst_group); |
| if (skb == NULL) |
| goto out; |
| |
| NETLINK_CB(skb).portid = nlk->portid; |
| NETLINK_CB(skb).dst_group = dst_group; |
| NETLINK_CB(skb).creds = scm.creds; |
| NETLINK_CB(skb).flags = netlink_skb_flags; |
| |
| err = -EFAULT; |
| if (memcpy_from_msg(skb_put(skb, len), msg, len)) { |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| err = security_netlink_send(sk, skb); |
| if (err) { |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| if (dst_group) { |
| atomic_inc(&skb->users); |
| netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); |
| } |
| err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT); |
| |
| out: |
| scm_destroy(&scm); |
| return err; |
| } |
| |
| static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, |
| int flags) |
| { |
| struct scm_cookie scm; |
| struct sock *sk = sock->sk; |
| struct netlink_sock *nlk = nlk_sk(sk); |
| int noblock = flags&MSG_DONTWAIT; |
| size_t copied; |
| struct sk_buff *skb, *data_skb; |
| int err, ret; |
| |
| if (flags&MSG_OOB) |
| return -EOPNOTSUPP; |
| |
| copied = 0; |
| |
| skb = skb_recv_datagram(sk, flags, noblock, &err); |
| if (skb == NULL) |
| goto out; |
| |
| data_skb = skb; |
| |
| #ifdef CONFIG_COMPAT_NETLINK_MESSAGES |
| if (unlikely(skb_shinfo(skb)->frag_list)) { |
| /* |
| * If this skb has a frag_list, then here that means that we |
| * will have to use the frag_list skb's data for compat tasks |
| * and the regular skb's data for normal (non-compat) tasks. |
| * |
| * If we need to send the compat skb, assign it to the |
| * 'data_skb' variable so that it will be used below for data |
| * copying. We keep 'skb' for everything else, including |
| * freeing both later. |
| */ |
| if (flags & MSG_CMSG_COMPAT) |
| data_skb = skb_shinfo(skb)->frag_list; |
| } |
| #endif |
| |
| /* Record the max length of recvmsg() calls for future allocations */ |
| nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len); |
| nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len, |
| 16384); |
| |
| copied = data_skb->len; |
| if (len < copied) { |
| msg->msg_flags |= MSG_TRUNC; |
| copied = len; |
| } |
| |
| skb_reset_transport_header(data_skb); |
| err = skb_copy_datagram_msg(data_skb, 0, msg, copied); |
| |
| if (msg->msg_name) { |
| DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name); |
| addr->nl_family = AF_NETLINK; |
| addr->nl_pad = 0; |
| addr->nl_pid = NETLINK_CB(skb).portid; |
| addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group); |
| msg->msg_namelen = sizeof(*addr); |
| } |
| |
| if (nlk->flags & NETLINK_F_RECV_PKTINFO) |
| netlink_cmsg_recv_pktinfo(msg, skb); |
| if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID) |
| netlink_cmsg_listen_all_nsid(sk, msg, skb); |
| |
| memset(&scm, 0, sizeof(scm)); |
| scm.creds = *NETLINK_CREDS(skb); |
| if (flags & MSG_TRUNC) |
| copied = data_skb->len; |
| |
| skb_free_datagram(sk, skb); |
| |
| if (nlk->cb_running && |
| atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { |
| ret = netlink_dump(sk); |
| if (ret) { |
| sk->sk_err = -ret; |
| sk->sk_error_report(sk); |
| } |
| } |
| |
| scm_recv(sock, msg, &scm, flags); |
| out: |
| netlink_rcv_wake(sk); |
| return err ? : copied; |
| } |
| |
| static void netlink_data_ready(struct sock *sk) |
| { |
| BUG(); |
| } |
| |
| /* |
| * We export these functions to other modules. They provide a |
| * complete set of kernel non-blocking support for message |
| * queueing. |
| */ |
| |
| struct sock * |
| __netlink_kernel_create(struct net *net, int unit, struct module *module, |
| struct netlink_kernel_cfg *cfg) |
| { |
| struct socket *sock; |
| struct sock *sk; |
| struct netlink_sock *nlk; |
| struct listeners *listeners = NULL; |
| struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL; |
| unsigned int groups; |
| |
| BUG_ON(!nl_table); |
| |
| if (unit < 0 || unit >= MAX_LINKS) |
| return NULL; |
| |
| if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) |
| return NULL; |
| |
| if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0) |
| goto out_sock_release_nosk; |
| |
| sk = sock->sk; |
| |
| if (!cfg || cfg->groups < 32) |
| groups = 32; |
| else |
| groups = cfg->groups; |
| |
| listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); |
| if (!listeners) |
| goto out_sock_release; |
| |
| sk->sk_data_ready = netlink_data_ready; |
| if (cfg && cfg->input) |
| nlk_sk(sk)->netlink_rcv = cfg->input; |
| |
| if (netlink_insert(sk, 0)) |
| goto out_sock_release; |
| |
| nlk = nlk_sk(sk); |
| nlk->flags |= NETLINK_F_KERNEL_SOCKET; |
| |
| netlink_table_grab(); |
| if (!nl_table[unit].registered) { |
| nl_table[unit].groups = groups; |
| rcu_assign_pointer(nl_table[unit].listeners, listeners); |
| nl_table[unit].cb_mutex = cb_mutex; |
| nl_table[unit].module = module; |
| if (cfg) { |
| nl_table[unit].bind = cfg->bind; |
| nl_table[unit].unbind = cfg->unbind; |
| nl_table[unit].flags = cfg->flags; |
| if (cfg->compare) |
| nl_table[unit].compare = cfg->compare; |
| } |
| nl_table[unit].registered = 1; |
| } else { |
| kfree(listeners); |
| nl_table[unit].registered++; |
| } |
| netlink_table_ungrab(); |
| return sk; |
| |
| out_sock_release: |
| kfree(listeners); |
| netlink_kernel_release(sk); |
| return NULL; |
| |
| out_sock_release_nosk: |
| sock_release(sock); |
| return NULL; |
| } |
| EXPORT_SYMBOL(__netlink_kernel_create); |
| |
| void |
| netlink_kernel_release(struct sock *sk) |
| { |
| if (sk == NULL || sk->sk_socket == NULL) |
| return; |
| |
| sock_release(sk->sk_socket); |
| } |
| EXPORT_SYMBOL(netlink_kernel_release); |
| |
| int __netlink_change_ngroups(struct sock *sk, unsigned int groups) |
| { |
| struct listeners *new, *old; |
| struct netlink_table *tbl = &nl_table[sk->sk_protocol]; |
| |
| if (groups < 32) |
| groups = 32; |
| |
| if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { |
| new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); |
| if (!new) |
| return -ENOMEM; |
| old = nl_deref_protected(tbl->listeners); |
| memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); |
| rcu_assign_pointer(tbl->listeners, new); |
| |
| kfree_rcu(old, rcu); |
| } |
| tbl->groups = groups; |
| |
| return 0; |
| } |
| |
| /** |
| * netlink_change_ngroups - change number of multicast groups |
| * |
| * This changes the number of multicast groups that are available |
| * on a certain netlink family. Note that it is not possible to |
| * change the number of groups to below 32. Also note that it does |
| * not implicitly call netlink_clear_multicast_users() when the |
| * number of groups is reduced. |
| * |
| * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). |
| * @groups: The new number of groups. |
| */ |
| int netlink_change_ngroups(struct sock *sk, unsigned int groups) |
| { |
| int err; |
| |
| netlink_table_grab(); |
| err = __netlink_change_ngroups(sk, groups); |
| netlink_table_ungrab(); |
| |
| return err; |
| } |
| |
| void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) |
| { |
| struct sock *sk; |
| struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; |
| |
| sk_for_each_bound(sk, &tbl->mc_list) |
| netlink_update_socket_mc(nlk_sk(sk), group, 0); |
| } |
| |
| struct nlmsghdr * |
| __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) |
| { |
| struct nlmsghdr *nlh; |
| int size = nlmsg_msg_size(len); |
| |
| nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size)); |
| nlh->nlmsg_type = type; |
| nlh->nlmsg_len = size; |
| nlh->nlmsg_flags = flags; |
| nlh->nlmsg_pid = portid; |
| nlh->nlmsg_seq = seq; |
| if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) |
| memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); |
| return nlh; |
| } |
| EXPORT_SYMBOL(__nlmsg_put); |
| |
| /* |
| * It looks a bit ugly. |
| * It would be better to create kernel thread. |
| */ |
| |
| static int netlink_dump(struct sock *sk) |
| { |
| struct netlink_sock *nlk = nlk_sk(sk); |
| struct netlink_callback *cb; |
| struct sk_buff *skb = NULL; |
| struct nlmsghdr *nlh; |
| int len, err = -ENOBUFS; |
| int alloc_min_size; |
| int alloc_size; |
| |
| mutex_lock(nlk->cb_mutex); |
| if (!nlk->cb_running) { |
| err = -EINVAL; |
| goto errout_skb; |
| } |
| |
| if (!netlink_rx_is_mmaped(sk) && |
| atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) |
| goto errout_skb; |
| |
| /* NLMSG_GOODSIZE is small to avoid high order allocations being |
| * required, but it makes sense to _attempt_ a 16K bytes allocation |
| * to reduce number of system calls on dump operations, if user |
| * ever provided a big enough buffer. |
| */ |
| cb = &nlk->cb; |
| alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); |
| |
| if (alloc_min_size < nlk->max_recvmsg_len) { |
| alloc_size = nlk->max_recvmsg_len; |
| skb = netlink_alloc_skb(sk, alloc_size, nlk->portid, |
| GFP_KERNEL | |
| __GFP_NOWARN | |
| __GFP_NORETRY); |
| } |
| if (!skb) { |
| alloc_size = alloc_min_size; |
| skb = netlink_alloc_skb(sk, alloc_size, nlk->portid, |
| GFP_KERNEL); |
| } |
| if (!skb) |
| goto errout_skb; |
| |
| /* Trim skb to allocated size. User is expected to provide buffer as |
| * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at |
| * netlink_recvmsg())). dump will pack as many smaller messages as |
| * could fit within the allocated skb. skb is typically allocated |
| * with larger space than required (could be as much as near 2x the |
| * requested size with align to next power of 2 approach). Allowing |
| * dump to use the excess space makes it difficult for a user to have a |
| * reasonable static buffer based on the expected largest dump of a |
| * single netdev. The outcome is MSG_TRUNC error. |
| */ |
| skb_reserve(skb, skb_tailroom(skb) - alloc_size); |
| netlink_skb_set_owner_r(skb, sk); |
| |
| len = cb->dump(skb, cb); |
| |
| if (len > 0) { |
| mutex_unlock(nlk->cb_mutex); |
| |
| if (sk_filter(sk, skb)) |
| kfree_skb(skb); |
| else |
| __netlink_sendskb(sk, skb); |
| return 0; |
| } |
| |
| nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI); |
| if (!nlh) |
| goto errout_skb; |
| |
| nl_dump_check_consistent(cb, nlh); |
| |
| memcpy(nlmsg_data(nlh), &len, sizeof(len)); |
| |
| if (sk_filter(sk, skb)) |
| kfree_skb(skb); |
| else |
| __netlink_sendskb(sk, skb); |
| |
| if (cb->done) |
| cb->done(cb); |
| |
| nlk->cb_running = false; |
| mutex_unlock(nlk->cb_mutex); |
| module_put(cb->module); |
| consume_skb(cb->skb); |
| return 0; |
| |
| errout_skb: |
| mutex_unlock(nlk->cb_mutex); |
| kfree_skb(skb); |
| return err; |
| } |
| |
| int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, |
| const struct nlmsghdr *nlh, |
| struct netlink_dump_control *control) |
| { |
| struct netlink_callback *cb; |
| struct sock *sk; |
| struct netlink_sock *nlk; |
| int ret; |
| |
| /* Memory mapped dump requests need to be copied to avoid looping |
| * on the pending state in netlink_mmap_sendmsg() while the CB hold |
| * a reference to the skb. |
| */ |
| if (netlink_skb_is_mmaped(skb)) { |
| skb = skb_copy(skb, GFP_KERNEL); |
| if (skb == NULL) |
| return -ENOBUFS; |
| } else |
| atomic_inc(&skb->users); |
| |
| sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); |
| if (sk == NULL) { |
| ret = -ECONNREFUSED; |
| goto error_free; |
| } |
| |
| nlk = nlk_sk(sk); |
| mutex_lock(nlk->cb_mutex); |
| /* A dump is in progress... */ |
| if (nlk->cb_running) { |
| ret = -EBUSY; |
| goto error_unlock; |
| } |
| /* add reference of module which cb->dump belongs to */ |
| if (!try_module_get(control->module)) { |
| ret = -EPROTONOSUPPORT; |
| goto error_unlock; |
| } |
| |
| cb = &nlk->cb; |
| memset(cb, 0, sizeof(*cb)); |
| cb->dump = control->dump; |
| cb->done = control->done; |
| cb->nlh = nlh; |
| cb->data = control->data; |
| cb->module = control->module; |
| cb->min_dump_alloc = control->min_dump_alloc; |
| cb->skb = skb; |
| |
| nlk->cb_running = true; |
| |
| mutex_unlock(nlk->cb_mutex); |
| |
| ret = netlink_dump(sk); |
| sock_put(sk); |
| |
| if (ret) |
| return ret; |
| |
| /* We successfully started a dump, by returning -EINTR we |
| * signal not to send ACK even if it was requested. |
| */ |
| return -EINTR; |
| |
| error_unlock: |
| sock_put(sk); |
| mutex_unlock(nlk->cb_mutex); |
| error_free: |
| kfree_skb(skb); |
| return ret; |
| } |
| EXPORT_SYMBOL(__netlink_dump_start); |
| |
| void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) |
| { |
| struct sk_buff *skb; |
| struct nlmsghdr *rep; |
| struct nlmsgerr *errmsg; |
| size_t payload = sizeof(*errmsg); |
| struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); |
| |
| /* Error messages get the original request appened, unless the user |
| * requests to cap the error message. |
| */ |
| if (!(nlk->flags & NETLINK_F_CAP_ACK) && err) |
| payload += nlmsg_len(nlh); |
| |
| skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload), |
| NETLINK_CB(in_skb).portid, GFP_KERNEL); |
| if (!skb) { |
| struct sock *sk; |
| |
| sk = netlink_lookup(sock_net(in_skb->sk), |
| in_skb->sk->sk_protocol, |
| NETLINK_CB(in_skb).portid); |
| if (sk) { |
| sk->sk_err = ENOBUFS; |
| sk->sk_error_report(sk); |
| sock_put(sk); |
| } |
| return; |
| } |
| |
| rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, |
| NLMSG_ERROR, payload, 0); |
| errmsg = nlmsg_data(rep); |
| errmsg->error = err; |
| memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); |
| netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); |
| } |
| EXPORT_SYMBOL(netlink_ack); |
| |
| int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, |
| struct nlmsghdr *)) |
| { |
| struct nlmsghdr *nlh; |
| int err; |
| |
| while (skb->len >= nlmsg_total_size(0)) { |
| int msglen; |
| |
| nlh = nlmsg_hdr(skb); |
| err = 0; |
| |
| if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) |
| return 0; |
| |
| /* Only requests are handled by the kernel */ |
| if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) |
| goto ack; |
| |
| /* Skip control messages */ |
| if (nlh->nlmsg_type < NLMSG_MIN_TYPE) |
| goto ack; |
| |
| err = cb(skb, nlh); |
| if (err == -EINTR) |
| goto skip; |
| |
| ack: |
| if (nlh->nlmsg_flags & NLM_F_ACK || err) |
| netlink_ack(skb, nlh, err); |
| |
| skip: |
| msglen = NLMSG_ALIGN(nlh->nlmsg_len); |
| if (msglen > skb->len) |
| msglen = skb->len; |
| skb_pull(skb, msglen); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(netlink_rcv_skb); |
| |
| /** |
| * nlmsg_notify - send a notification netlink message |
| * @sk: netlink socket to use |
| * @skb: notification message |
| * @portid: destination netlink portid for reports or 0 |
| * @group: destination multicast group or 0 |
| * @report: 1 to report back, 0 to disable |
| * @flags: allocation flags |
| */ |
| int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, |
| unsigned int group, int report, gfp_t flags) |
| { |
| int err = 0; |
| |
| if (group) { |
| int exclude_portid = 0; |
| |
| if (report) { |
| atomic_inc(&skb->users); |
| exclude_portid = portid; |
| } |
| |
| /* errors reported via destination sk->sk_err, but propagate |
| * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ |
| err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); |
| } |
| |
| if (report) { |
| int |