| /* auditfilter.c -- filtering of audit events |
| * |
| * Copyright 2003-2004 Red Hat, Inc. |
| * Copyright 2005 Hewlett-Packard Development Company, L.P. |
| * Copyright 2005 IBM Corporation |
| * |
| * 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. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/audit.h> |
| #include <linux/kthread.h> |
| #include <linux/mutex.h> |
| #include <linux/fs.h> |
| #include <linux/namei.h> |
| #include <linux/netlink.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/security.h> |
| #include "audit.h" |
| |
| /* |
| * Locking model: |
| * |
| * audit_filter_mutex: |
| * Synchronizes writes and blocking reads of audit's filterlist |
| * data. Rcu is used to traverse the filterlist and access |
| * contents of structs audit_entry, audit_watch and opaque |
| * LSM rules during filtering. If modified, these structures |
| * must be copied and replace their counterparts in the filterlist. |
| * An audit_parent struct is not accessed during filtering, so may |
| * be written directly provided audit_filter_mutex is held. |
| */ |
| |
| /* Audit filter lists, defined in <linux/audit.h> */ |
| struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { |
| LIST_HEAD_INIT(audit_filter_list[0]), |
| LIST_HEAD_INIT(audit_filter_list[1]), |
| LIST_HEAD_INIT(audit_filter_list[2]), |
| LIST_HEAD_INIT(audit_filter_list[3]), |
| LIST_HEAD_INIT(audit_filter_list[4]), |
| LIST_HEAD_INIT(audit_filter_list[5]), |
| #if AUDIT_NR_FILTERS != 6 |
| #error Fix audit_filter_list initialiser |
| #endif |
| }; |
| static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = { |
| LIST_HEAD_INIT(audit_rules_list[0]), |
| LIST_HEAD_INIT(audit_rules_list[1]), |
| LIST_HEAD_INIT(audit_rules_list[2]), |
| LIST_HEAD_INIT(audit_rules_list[3]), |
| LIST_HEAD_INIT(audit_rules_list[4]), |
| LIST_HEAD_INIT(audit_rules_list[5]), |
| }; |
| |
| DEFINE_MUTEX(audit_filter_mutex); |
| |
| static inline void audit_free_rule(struct audit_entry *e) |
| { |
| int i; |
| struct audit_krule *erule = &e->rule; |
| |
| /* some rules don't have associated watches */ |
| if (erule->watch) |
| audit_put_watch(erule->watch); |
| if (erule->fields) |
| for (i = 0; i < erule->field_count; i++) { |
| struct audit_field *f = &erule->fields[i]; |
| kfree(f->lsm_str); |
| security_audit_rule_free(f->lsm_rule); |
| } |
| kfree(erule->fields); |
| kfree(erule->filterkey); |
| kfree(e); |
| } |
| |
| void audit_free_rule_rcu(struct rcu_head *head) |
| { |
| struct audit_entry *e = container_of(head, struct audit_entry, rcu); |
| audit_free_rule(e); |
| } |
| |
| /* Initialize an audit filterlist entry. */ |
| static inline struct audit_entry *audit_init_entry(u32 field_count) |
| { |
| struct audit_entry *entry; |
| struct audit_field *fields; |
| |
| entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
| if (unlikely(!entry)) |
| return NULL; |
| |
| fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL); |
| if (unlikely(!fields)) { |
| kfree(entry); |
| return NULL; |
| } |
| entry->rule.fields = fields; |
| |
| return entry; |
| } |
| |
| /* Unpack a filter field's string representation from user-space |
| * buffer. */ |
| char *audit_unpack_string(void **bufp, size_t *remain, size_t len) |
| { |
| char *str; |
| |
| if (!*bufp || (len == 0) || (len > *remain)) |
| return ERR_PTR(-EINVAL); |
| |
| /* Of the currently implemented string fields, PATH_MAX |
| * defines the longest valid length. |
| */ |
| if (len > PATH_MAX) |
| return ERR_PTR(-ENAMETOOLONG); |
| |
| str = kmalloc(len + 1, GFP_KERNEL); |
| if (unlikely(!str)) |
| return ERR_PTR(-ENOMEM); |
| |
| memcpy(str, *bufp, len); |
| str[len] = 0; |
| *bufp += len; |
| *remain -= len; |
| |
| return str; |
| } |
| |
| /* Translate an inode field to kernel respresentation. */ |
| static inline int audit_to_inode(struct audit_krule *krule, |
| struct audit_field *f) |
| { |
| if (krule->listnr != AUDIT_FILTER_EXIT || |
| krule->watch || krule->inode_f || krule->tree || |
| (f->op != Audit_equal && f->op != Audit_not_equal)) |
| return -EINVAL; |
| |
| krule->inode_f = f; |
| return 0; |
| } |
| |
| static __u32 *classes[AUDIT_SYSCALL_CLASSES]; |
| |
| int __init audit_register_class(int class, unsigned *list) |
| { |
| __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL); |
| if (!p) |
| return -ENOMEM; |
| while (*list != ~0U) { |
| unsigned n = *list++; |
| if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) { |
| kfree(p); |
| return -EINVAL; |
| } |
| p[AUDIT_WORD(n)] |= AUDIT_BIT(n); |
| } |
| if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) { |
| kfree(p); |
| return -EINVAL; |
| } |
| classes[class] = p; |
| return 0; |
| } |
| |
| int audit_match_class(int class, unsigned syscall) |
| { |
| if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32)) |
| return 0; |
| if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class])) |
| return 0; |
| return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall); |
| } |
| |
| #ifdef CONFIG_AUDITSYSCALL |
| static inline int audit_match_class_bits(int class, u32 *mask) |
| { |
| int i; |
| |
| if (classes[class]) { |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| if (mask[i] & classes[class][i]) |
| return 0; |
| } |
| return 1; |
| } |
| |
| static int audit_match_signal(struct audit_entry *entry) |
| { |
| struct audit_field *arch = entry->rule.arch_f; |
| |
| if (!arch) { |
| /* When arch is unspecified, we must check both masks on biarch |
| * as syscall number alone is ambiguous. */ |
| return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, |
| entry->rule.mask) && |
| audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, |
| entry->rule.mask)); |
| } |
| |
| switch(audit_classify_arch(arch->val)) { |
| case 0: /* native */ |
| return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, |
| entry->rule.mask)); |
| case 1: /* 32bit on biarch */ |
| return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, |
| entry->rule.mask)); |
| default: |
| return 1; |
| } |
| } |
| #endif |
| |
| /* Common user-space to kernel rule translation. */ |
| static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) |
| { |
| unsigned listnr; |
| struct audit_entry *entry; |
| int i, err; |
| |
| err = -EINVAL; |
| listnr = rule->flags & ~AUDIT_FILTER_PREPEND; |
| switch(listnr) { |
| default: |
| goto exit_err; |
| case AUDIT_FILTER_USER: |
| case AUDIT_FILTER_TYPE: |
| #ifdef CONFIG_AUDITSYSCALL |
| case AUDIT_FILTER_ENTRY: |
| case AUDIT_FILTER_EXIT: |
| case AUDIT_FILTER_TASK: |
| #endif |
| ; |
| } |
| if (unlikely(rule->action == AUDIT_POSSIBLE)) { |
| printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n"); |
| goto exit_err; |
| } |
| if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS) |
| goto exit_err; |
| if (rule->field_count > AUDIT_MAX_FIELDS) |
| goto exit_err; |
| |
| err = -ENOMEM; |
| entry = audit_init_entry(rule->field_count); |
| if (!entry) |
| goto exit_err; |
| |
| entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND; |
| entry->rule.listnr = listnr; |
| entry->rule.action = rule->action; |
| entry->rule.field_count = rule->field_count; |
| |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| entry->rule.mask[i] = rule->mask[i]; |
| |
| for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) { |
| int bit = AUDIT_BITMASK_SIZE * 32 - i - 1; |
| __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)]; |
| __u32 *class; |
| |
| if (!(*p & AUDIT_BIT(bit))) |
| continue; |
| *p &= ~AUDIT_BIT(bit); |
| class = classes[i]; |
| if (class) { |
| int j; |
| for (j = 0; j < AUDIT_BITMASK_SIZE; j++) |
| entry->rule.mask[j] |= class[j]; |
| } |
| } |
| |
| return entry; |
| |
| exit_err: |
| return ERR_PTR(err); |
| } |
| |
| static u32 audit_ops[] = |
| { |
| [Audit_equal] = AUDIT_EQUAL, |
| [Audit_not_equal] = AUDIT_NOT_EQUAL, |
| [Audit_bitmask] = AUDIT_BIT_MASK, |
| [Audit_bittest] = AUDIT_BIT_TEST, |
| [Audit_lt] = AUDIT_LESS_THAN, |
| [Audit_gt] = AUDIT_GREATER_THAN, |
| [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL, |
| [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL, |
| }; |
| |
| static u32 audit_to_op(u32 op) |
| { |
| u32 n; |
| for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++) |
| ; |
| return n; |
| } |
| |
| |
| /* Translate struct audit_rule to kernel's rule respresentation. |
| * Exists for backward compatibility with userspace. */ |
| static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) |
| { |
| struct audit_entry *entry; |
| int err = 0; |
| int i; |
| |
| entry = audit_to_entry_common(rule); |
| if (IS_ERR(entry)) |
| goto exit_nofree; |
| |
| for (i = 0; i < rule->field_count; i++) { |
| struct audit_field *f = &entry->rule.fields[i]; |
| u32 n; |
| |
| n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS); |
| |
| /* Support for legacy operators where |
| * AUDIT_NEGATE bit signifies != and otherwise assumes == */ |
| if (n & AUDIT_NEGATE) |
| f->op = Audit_not_equal; |
| else if (!n) |
| f->op = Audit_equal; |
| else |
| f->op = audit_to_op(n); |
| |
| entry->rule.vers_ops = (n & AUDIT_OPERATORS) ? 2 : 1; |
| |
| f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); |
| f->val = rule->values[i]; |
| |
| err = -EINVAL; |
| if (f->op == Audit_bad) |
| goto exit_free; |
| |
| switch(f->type) { |
| default: |
| goto exit_free; |
| case AUDIT_PID: |
| case AUDIT_UID: |
| case AUDIT_EUID: |
| case AUDIT_SUID: |
| case AUDIT_FSUID: |
| case AUDIT_GID: |
| case AUDIT_EGID: |
| case AUDIT_SGID: |
| case AUDIT_FSGID: |
| case AUDIT_LOGINUID: |
| case AUDIT_PERS: |
| case AUDIT_MSGTYPE: |
| case AUDIT_PPID: |
| case AUDIT_DEVMAJOR: |
| case AUDIT_DEVMINOR: |
| case AUDIT_EXIT: |
| case AUDIT_SUCCESS: |
| /* bit ops are only useful on syscall args */ |
| if (f->op == Audit_bitmask || f->op == Audit_bittest) |
| goto exit_free; |
| break; |
| case AUDIT_ARG0: |
| case AUDIT_ARG1: |
| case AUDIT_ARG2: |
| case AUDIT_ARG3: |
| break; |
| /* arch is only allowed to be = or != */ |
| case AUDIT_ARCH: |
| if (f->op != Audit_not_equal && f->op != Audit_equal) |
| goto exit_free; |
| entry->rule.arch_f = f; |
| break; |
| case AUDIT_PERM: |
| if (f->val & ~15) |
| goto exit_free; |
| break; |
| case AUDIT_FILETYPE: |
| if ((f->val & ~S_IFMT) > S_IFMT) |
| goto exit_free; |
| break; |
| case AUDIT_INODE: |
| err = audit_to_inode(&entry->rule, f); |
| if (err) |
| goto exit_free; |
| break; |
| } |
| } |
| |
| if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
| entry->rule.inode_f = NULL; |
| |
| exit_nofree: |
| return entry; |
| |
| exit_free: |
| audit_free_rule(entry); |
| return ERR_PTR(err); |
| } |
| |
| /* Translate struct audit_rule_data to kernel's rule respresentation. */ |
| static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, |
| size_t datasz) |
| { |
| int err = 0; |
| struct audit_entry *entry; |
| void *bufp; |
| size_t remain = datasz - sizeof(struct audit_rule_data); |
| int i; |
| char *str; |
| |
| entry = audit_to_entry_common((struct audit_rule *)data); |
| if (IS_ERR(entry)) |
| goto exit_nofree; |
| |
| bufp = data->buf; |
| entry->rule.vers_ops = 2; |
| for (i = 0; i < data->field_count; i++) { |
| struct audit_field *f = &entry->rule.fields[i]; |
| |
| err = -EINVAL; |
| |
| f->op = audit_to_op(data->fieldflags[i]); |
| if (f->op == Audit_bad) |
| goto exit_free; |
| |
| f->type = data->fields[i]; |
| f->val = data->values[i]; |
| f->lsm_str = NULL; |
| f->lsm_rule = NULL; |
| switch(f->type) { |
| case AUDIT_PID: |
| case AUDIT_UID: |
| case AUDIT_EUID: |
| case AUDIT_SUID: |
| case AUDIT_FSUID: |
| case AUDIT_GID: |
| case AUDIT_EGID: |
| case AUDIT_SGID: |
| case AUDIT_FSGID: |
| case AUDIT_LOGINUID: |
| case AUDIT_PERS: |
| case AUDIT_MSGTYPE: |
| case AUDIT_PPID: |
| case AUDIT_DEVMAJOR: |
| case AUDIT_DEVMINOR: |
| case AUDIT_EXIT: |
| case AUDIT_SUCCESS: |
| case AUDIT_ARG0: |
| case AUDIT_ARG1: |
| case AUDIT_ARG2: |
| case AUDIT_ARG3: |
| break; |
| case AUDIT_ARCH: |
| entry->rule.arch_f = f; |
| break; |
| case AUDIT_SUBJ_USER: |
| case AUDIT_SUBJ_ROLE: |
| case AUDIT_SUBJ_TYPE: |
| case AUDIT_SUBJ_SEN: |
| case AUDIT_SUBJ_CLR: |
| case AUDIT_OBJ_USER: |
| case AUDIT_OBJ_ROLE: |
| case AUDIT_OBJ_TYPE: |
| case AUDIT_OBJ_LEV_LOW: |
| case AUDIT_OBJ_LEV_HIGH: |
| str = audit_unpack_string(&bufp, &remain, f->val); |
| if (IS_ERR(str)) |
| goto exit_free; |
| entry->rule.buflen += f->val; |
| |
| err = security_audit_rule_init(f->type, f->op, str, |
| (void **)&f->lsm_rule); |
| /* Keep currently invalid fields around in case they |
| * become valid after a policy reload. */ |
| if (err == -EINVAL) { |
| printk(KERN_WARNING "audit rule for LSM " |
| "\'%s\' is invalid\n", str); |
| err = 0; |
| } |
| if (err) { |
| kfree(str); |
| goto exit_free; |
| } else |
| f->lsm_str = str; |
| break; |
| case AUDIT_WATCH: |
| str = audit_unpack_string(&bufp, &remain, f->val); |
| if (IS_ERR(str)) |
| goto exit_free; |
| entry->rule.buflen += f->val; |
| |
| err = audit_to_watch(&entry->rule, str, f->val, f->op); |
| if (err) { |
| kfree(str); |
| goto exit_free; |
| } |
| break; |
| case AUDIT_DIR: |
| str = audit_unpack_string(&bufp, &remain, f->val); |
| if (IS_ERR(str)) |
| goto exit_free; |
| entry->rule.buflen += f->val; |
| |
| err = audit_make_tree(&entry->rule, str, f->op); |
| kfree(str); |
| if (err) |
| goto exit_free; |
| break; |
| case AUDIT_INODE: |
| err = audit_to_inode(&entry->rule, f); |
| if (err) |
| goto exit_free; |
| break; |
| case AUDIT_FILTERKEY: |
| err = -EINVAL; |
| if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) |
| goto exit_free; |
| str = audit_unpack_string(&bufp, &remain, f->val); |
| if (IS_ERR(str)) |
| goto exit_free; |
| entry->rule.buflen += f->val; |
| entry->rule.filterkey = str; |
| break; |
| case AUDIT_PERM: |
| if (f->val & ~15) |
| goto exit_free; |
| break; |
| case AUDIT_FILETYPE: |
| if ((f->val & ~S_IFMT) > S_IFMT) |
| goto exit_free; |
| break; |
| default: |
| goto exit_free; |
| } |
| } |
| |
| if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) |
| entry->rule.inode_f = NULL; |
| |
| exit_nofree: |
| return entry; |
| |
| exit_free: |
| audit_free_rule(entry); |
| return ERR_PTR(err); |
| } |
| |
| /* Pack a filter field's string representation into data block. */ |
| static inline size_t audit_pack_string(void **bufp, const char *str) |
| { |
| size_t len = strlen(str); |
| |
| memcpy(*bufp, str, len); |
| *bufp += len; |
| |
| return len; |
| } |
| |
| /* Translate kernel rule respresentation to struct audit_rule. |
| * Exists for backward compatibility with userspace. */ |
| static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule) |
| { |
| struct audit_rule *rule; |
| int i; |
| |
| rule = kzalloc(sizeof(*rule), GFP_KERNEL); |
| if (unlikely(!rule)) |
| return NULL; |
| |
| rule->flags = krule->flags | krule->listnr; |
| rule->action = krule->action; |
| rule->field_count = krule->field_count; |
| for (i = 0; i < rule->field_count; i++) { |
| rule->values[i] = krule->fields[i].val; |
| rule->fields[i] = krule->fields[i].type; |
| |
| if (krule->vers_ops == 1) { |
| if (krule->fields[i].op == Audit_not_equal) |
| rule->fields[i] |= AUDIT_NEGATE; |
| } else { |
| rule->fields[i] |= audit_ops[krule->fields[i].op]; |
| } |
| } |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i]; |
| |
| return rule; |
| } |
| |
| /* Translate kernel rule respresentation to struct audit_rule_data. */ |
| static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) |
| { |
| struct audit_rule_data *data; |
| void *bufp; |
| int i; |
| |
| data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); |
| if (unlikely(!data)) |
| return NULL; |
| memset(data, 0, sizeof(*data)); |
| |
| data->flags = krule->flags | krule->listnr; |
| data->action = krule->action; |
| data->field_count = krule->field_count; |
| bufp = data->buf; |
| for (i = 0; i < data->field_count; i++) { |
| struct audit_field *f = &krule->fields[i]; |
| |
| data->fields[i] = f->type; |
| data->fieldflags[i] = audit_ops[f->op]; |
| switch(f->type) { |
| case AUDIT_SUBJ_USER: |
| case AUDIT_SUBJ_ROLE: |
| case AUDIT_SUBJ_TYPE: |
| case AUDIT_SUBJ_SEN: |
| case AUDIT_SUBJ_CLR: |
| case AUDIT_OBJ_USER: |
| case AUDIT_OBJ_ROLE: |
| case AUDIT_OBJ_TYPE: |
| case AUDIT_OBJ_LEV_LOW: |
| case AUDIT_OBJ_LEV_HIGH: |
| data->buflen += data->values[i] = |
| audit_pack_string(&bufp, f->lsm_str); |
| break; |
| case AUDIT_WATCH: |
| data->buflen += data->values[i] = |
| audit_pack_string(&bufp, |
| audit_watch_path(krule->watch)); |
| break; |
| case AUDIT_DIR: |
| data->buflen += data->values[i] = |
| audit_pack_string(&bufp, |
| audit_tree_path(krule->tree)); |
| break; |
| case AUDIT_FILTERKEY: |
| data->buflen += data->values[i] = |
| audit_pack_string(&bufp, krule->filterkey); |
| break; |
| default: |
| data->values[i] = f->val; |
| } |
| } |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; |
| |
| return data; |
| } |
| |
| /* Compare two rules in kernel format. Considered success if rules |
| * don't match. */ |
| static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) |
| { |
| int i; |
| |
| if (a->flags != b->flags || |
| a->listnr != b->listnr || |
| a->action != b->action || |
| a->field_count != b->field_count) |
| return 1; |
| |
| for (i = 0; i < a->field_count; i++) { |
| if (a->fields[i].type != b->fields[i].type || |
| a->fields[i].op != b->fields[i].op) |
| return 1; |
| |
| switch(a->fields[i].type) { |
| case AUDIT_SUBJ_USER: |
| case AUDIT_SUBJ_ROLE: |
| case AUDIT_SUBJ_TYPE: |
| case AUDIT_SUBJ_SEN: |
| case AUDIT_SUBJ_CLR: |
| case AUDIT_OBJ_USER: |
| case AUDIT_OBJ_ROLE: |
| case AUDIT_OBJ_TYPE: |
| case AUDIT_OBJ_LEV_LOW: |
| case AUDIT_OBJ_LEV_HIGH: |
| if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str)) |
| return 1; |
| break; |
| case AUDIT_WATCH: |
| if (strcmp(audit_watch_path(a->watch), |
| audit_watch_path(b->watch))) |
| return 1; |
| break; |
| case AUDIT_DIR: |
| if (strcmp(audit_tree_path(a->tree), |
| audit_tree_path(b->tree))) |
| return 1; |
| break; |
| case AUDIT_FILTERKEY: |
| /* both filterkeys exist based on above type compare */ |
| if (strcmp(a->filterkey, b->filterkey)) |
| return 1; |
| break; |
| default: |
| if (a->fields[i].val != b->fields[i].val) |
| return 1; |
| } |
| } |
| |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| if (a->mask[i] != b->mask[i]) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* Duplicate LSM field information. The lsm_rule is opaque, so must be |
| * re-initialized. */ |
| static inline int audit_dupe_lsm_field(struct audit_field *df, |
| struct audit_field *sf) |
| { |
| int ret = 0; |
| char *lsm_str; |
| |
| /* our own copy of lsm_str */ |
| lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL); |
| if (unlikely(!lsm_str)) |
| return -ENOMEM; |
| df->lsm_str = lsm_str; |
| |
| /* our own (refreshed) copy of lsm_rule */ |
| ret = security_audit_rule_init(df->type, df->op, df->lsm_str, |
| (void **)&df->lsm_rule); |
| /* Keep currently invalid fields around in case they |
| * become valid after a policy reload. */ |
| if (ret == -EINVAL) { |
| printk(KERN_WARNING "audit rule for LSM \'%s\' is " |
| "invalid\n", df->lsm_str); |
| ret = 0; |
| } |
| |
| return ret; |
| } |
| |
| /* Duplicate an audit rule. This will be a deep copy with the exception |
| * of the watch - that pointer is carried over. The LSM specific fields |
| * will be updated in the copy. The point is to be able to replace the old |
| * rule with the new rule in the filterlist, then free the old rule. |
| * The rlist element is undefined; list manipulations are handled apart from |
| * the initial copy. */ |
| struct audit_entry *audit_dupe_rule(struct audit_krule *old) |
| { |
| u32 fcount = old->field_count; |
| struct audit_entry *entry; |
| struct audit_krule *new; |
| char *fk; |
| int i, err = 0; |
| |
| entry = audit_init_entry(fcount); |
| if (unlikely(!entry)) |
| return ERR_PTR(-ENOMEM); |
| |
| new = &entry->rule; |
| new->vers_ops = old->vers_ops; |
| new->flags = old->flags; |
| new->listnr = old->listnr; |
| new->action = old->action; |
| for (i = 0; i < AUDIT_BITMASK_SIZE; i++) |
| new->mask[i] = old->mask[i]; |
| new->prio = old->prio; |
| new->buflen = old->buflen; |
| new->inode_f = old->inode_f; |
| new->field_count = old->field_count; |
| |
| /* |
| * note that we are OK with not refcounting here; audit_match_tree() |
| * never dereferences tree and we can't get false positives there |
| * since we'd have to have rule gone from the list *and* removed |
| * before the chunks found by lookup had been allocated, i.e. before |
| * the beginning of list scan. |
| */ |
| new->tree = old->tree; |
| memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); |
| |
| /* deep copy this information, updating the lsm_rule fields, because |
| * the originals will all be freed when the old rule is freed. */ |
| for (i = 0; i < fcount; i++) { |
| switch (new->fields[i].type) { |
| case AUDIT_SUBJ_USER: |
| case AUDIT_SUBJ_ROLE: |
| case AUDIT_SUBJ_TYPE: |
| case AUDIT_SUBJ_SEN: |
| case AUDIT_SUBJ_CLR: |
| case AUDIT_OBJ_USER: |
| case AUDIT_OBJ_ROLE: |
| case AUDIT_OBJ_TYPE: |
| case AUDIT_OBJ_LEV_LOW: |
| case AUDIT_OBJ_LEV_HIGH: |
| err = audit_dupe_lsm_field(&new->fields[i], |
| &old->fields[i]); |
| break; |
| case AUDIT_FILTERKEY: |
| fk = kstrdup(old->filterkey, GFP_KERNEL); |
| if (unlikely(!fk)) |
| err = -ENOMEM; |
| else |
| new->filterkey = fk; |
| } |
| if (err) { |
| audit_free_rule(entry); |
| return ERR_PTR(err); |
| } |
| } |
| |
| if (old->watch) { |
| audit_get_watch(old->watch); |
| new->watch = old->watch; |
| } |
| |
| return entry; |
| } |
| |
| /* Find an existing audit rule. |
| * Caller must hold audit_filter_mutex to prevent stale rule data. */ |
| static struct audit_entry *audit_find_rule(struct audit_entry *entry, |
| struct list_head **p) |
| { |
| struct audit_entry *e, *found = NULL; |
| struct list_head *list; |
| int h; |
| |
| if (entry->rule.inode_f) { |
| h = audit_hash_ino(entry->rule.inode_f->val); |
| *p = list = &audit_inode_hash[h]; |
| } else if (entry->rule.watch) { |
| /* we don't know the inode number, so must walk entire hash */ |
| for (h = 0; h < AUDIT_INODE_BUCKETS; h++) { |
| list = &audit_inode_hash[h]; |
| list_for_each_entry(e, list, list) |
| if (!audit_compare_rule(&entry->rule, &e->rule)) { |
| found = e; |
| goto out; |
| } |
| } |
| goto out; |
| } else { |
| *p = list = &audit_filter_list[entry->rule.listnr]; |
| } |
| |
| list_for_each_entry(e, list, list) |
| if (!audit_compare_rule(&entry->rule, &e->rule)) { |
| found = e; |
| goto out; |
| } |
| |
| out: |
| return found; |
| } |
| |
| static u64 prio_low = ~0ULL/2; |
| static u64 prio_high = ~0ULL/2 - 1; |
| |
| /* Add rule to given filterlist if not a duplicate. */ |
| static inline int audit_add_rule(struct audit_entry *entry) |
| { |
| struct audit_entry *e; |
| struct audit_watch *watch = entry->rule.watch; |
| struct audit_tree *tree = entry->rule.tree; |
| struct list_head *list; |
| int err; |
| #ifdef CONFIG_AUDITSYSCALL |
| int dont_count = 0; |
| |
| /* If either of these, don't count towards total */ |
| if (entry->rule.listnr == AUDIT_FILTER_USER || |
| entry->rule.listnr == AUDIT_FILTER_TYPE) |
| dont_count = 1; |
| #endif |
| |
| mutex_lock(&audit_filter_mutex); |
| e = audit_find_rule(entry, &list); |
| if (e) { |
| mutex_unlock(&audit_filter_mutex); |
| err = -EEXIST; |
| /* normally audit_add_tree_rule() will free it on failure */ |
| if (tree) |
| audit_put_tree(tree); |
| goto error; |
| } |
| |
| if (watch) { |
| /* audit_filter_mutex is dropped and re-taken during this call */ |
| err = audit_add_watch(&entry->rule, &list); |
| if (err) { |
| mutex_unlock(&audit_filter_mutex); |
| goto error; |
| } |
| } |
| if (tree) { |
| err = audit_add_tree_rule(&entry->rule); |
| if (err) { |
| mutex_unlock(&audit_filter_mutex); |
| goto error; |
| } |
| } |
| |
| entry->rule.prio = ~0ULL; |
| if (entry->rule.listnr == AUDIT_FILTER_EXIT) { |
| if (entry->rule.flags & AUDIT_FILTER_PREPEND) |
| entry->rule.prio = ++prio_high; |
| else |
| entry->rule.prio = --prio_low; |
| } |
| |
| if (entry->rule.flags & AUDIT_FILTER_PREPEND) { |
| list_add(&entry->rule.list, |
| &audit_rules_list[entry->rule.listnr]); |
| list_add_rcu(&entry->list, list); |
| entry->rule.flags &= ~AUDIT_FILTER_PREPEND; |
| } else { |
| list_add_tail(&entry->rule.list, |
| &audit_rules_list[entry->rule.listnr]); |
| list_add_tail_rcu(&entry->list, list); |
| } |
| #ifdef CONFIG_AUDITSYSCALL |
| if (!dont_count) |
| audit_n_rules++; |
| |
| if (!audit_match_signal(entry)) |
| audit_signals++; |
| #endif |
| mutex_unlock(&audit_filter_mutex); |
| |
| return 0; |
| |
| error: |
| if (watch) |
| audit_put_watch(watch); /* tmp watch, matches initial get */ |
| return err; |
| } |
| |
| /* Remove an existing rule from filterlist. */ |
| static inline int audit_del_rule(struct audit_entry *entry) |
| { |
| struct audit_entry *e; |
| struct audit_watch *watch = entry->rule.watch; |
| struct audit_tree *tree = entry->rule.tree; |
| struct list_head *list; |
| int ret = 0; |
| #ifdef CONFIG_AUDITSYSCALL |
| int dont_count = 0; |
| |
| /* If either of these, don't count towards total */ |
| if (entry->rule.listnr == AUDIT_FILTER_USER || |
| entry->rule.listnr == AUDIT_FILTER_TYPE) |
| dont_count = 1; |
| #endif |
| |
| mutex_lock(&audit_filter_mutex); |
| e = audit_find_rule(entry, &list); |
| if (!e) { |
| mutex_unlock(&audit_filter_mutex); |
| ret = -ENOENT; |
| goto out; |
| } |
| |
| if (e->rule.watch) |
| audit_remove_watch_rule(&e->rule); |
| |
| if (e->rule.tree) |
| audit_remove_tree_rule(&e->rule); |
| |
| list_del_rcu(&e->list); |
| list_del(&e->rule.list); |
| call_rcu(&e->rcu, audit_free_rule_rcu); |
| |
| #ifdef CONFIG_AUDITSYSCALL |
| if (!dont_count) |
| audit_n_rules--; |
| |
| if (!audit_match_signal(entry)) |
| audit_signals--; |
| #endif |
| mutex_unlock(&audit_filter_mutex); |
| |
| out: |
| if (watch) |
| audit_put_watch(watch); /* match initial get */ |
| if (tree) |
| audit_put_tree(tree); /* that's the temporary one */ |
| |
| return ret; |
| } |
| |
| /* List rules using struct audit_rule. Exists for backward |
| * compatibility with userspace. */ |
| static void audit_list(int pid, int seq, struct sk_buff_head *q) |
| { |
| struct sk_buff *skb; |
| struct audit_krule *r; |
| int i; |
| |
| /* This is a blocking read, so use audit_filter_mutex instead of rcu |
| * iterator to sync with list writers. */ |
| for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| list_for_each_entry(r, &audit_rules_list[i], list) { |
| struct audit_rule *rule; |
| |
| rule = audit_krule_to_rule(r); |
| if (unlikely(!rule)) |
| break; |
| skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, |
| rule, sizeof(*rule)); |
| if (skb) |
| skb_queue_tail(q, skb); |
| kfree(rule); |
| } |
| } |
| skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); |
| if (skb) |
| skb_queue_tail(q, skb); |
| } |
| |
| /* List rules using struct audit_rule_data. */ |
| static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) |
| { |
| struct sk_buff *skb; |
| struct audit_krule *r; |
| int i; |
| |
| /* This is a blocking read, so use audit_filter_mutex instead of rcu |
| * iterator to sync with list writers. */ |
| for (i=0; i<AUDIT_NR_FILTERS; i++) { |
| list_for_each_entry(r, &audit_rules_list[i], list) { |
| struct audit_rule_data *data; |
| |
| data = audit_krule_to_data(r); |
| if (unlikely(!data)) |
| break; |
| skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, |
| data, sizeof(*data) + data->buflen); |
| if (skb) |
| skb_queue_tail(q, skb); |
| kfree(data); |
| } |
| } |
| skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); |
| if (skb) |
| skb_queue_tail(q, skb); |
| } |
| |
| /* Log rule additions and removals */ |
| static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid, |
| char *action, struct audit_krule *rule, |
| int res) |
| { |
| struct audit_buffer *ab; |
| |
| if (!audit_enabled) |
| return; |
| |
| ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
| if (!ab) |
| return; |
| audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid); |
| if (sid) { |
| char *ctx = NULL; |
| u32 len; |
| if (security_secid_to_secctx(sid, &ctx, &len)) |
| audit_log_format(ab, " ssid=%u", sid); |
| else { |
| audit_log_format(ab, " subj=%s", ctx); |
| security_release_secctx(ctx, len); |
| } |
| } |
| audit_log_format(ab, " op="); |
| audit_log_string(ab, action); |
| audit_log_key(ab, rule->filterkey); |
| audit_log_format(ab, " list=%d res=%d", rule->listnr, res); |
| audit_log_end(ab); |
| } |
| |
| /** |
| * audit_receive_filter - apply all rules to the specified message type |
| * @type: audit message type |
| * @pid: target pid for netlink audit messages |
| * @uid: target uid for netlink audit messages |
| * @seq: netlink audit message sequence (serial) number |
| * @data: payload data |
| * @datasz: size of payload data |
| * @loginuid: loginuid of sender |
| * @sessionid: sessionid for netlink audit message |
| * @sid: SE Linux Security ID of sender |
| */ |
| int audit_receive_filter(int type, int pid, int uid, int seq, void *data, |
| size_t datasz, uid_t loginuid, u32 sessionid, u32 sid) |
| { |
| struct task_struct *tsk; |
| struct audit_netlink_list *dest; |
| int err = 0; |
| struct audit_entry *entry; |
| |
| switch (type) { |
| case AUDIT_LIST: |
| case AUDIT_LIST_RULES: |
| /* We can't just spew out the rules here because we might fill |
| * the available socket buffer space and deadlock waiting for |
| * auditctl to read from it... which isn't ever going to |
| * happen if we're actually running in the context of auditctl |
| * trying to _send_ the stuff */ |
| |
| dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); |
| if (!dest) |
| return -ENOMEM; |
| dest->pid = pid; |
| skb_queue_head_init(&dest->q); |
| |
| mutex_lock(&audit_filter_mutex); |
| if (type == AUDIT_LIST) |
| audit_list(pid, seq, &dest->q); |
| else |
| audit_list_rules(pid, seq, &dest->q); |
| mutex_unlock(&audit_filter_mutex); |
| |
| tsk = kthread_run(audit_send_list, dest, "audit_send_list"); |
| if (IS_ERR(tsk)) { |
| skb_queue_purge(&dest->q); |
| kfree(dest); |
| err = PTR_ERR(tsk); |
| } |
| break; |
| case AUDIT_ADD: |
| case AUDIT_ADD_RULE: |
| if (type == AUDIT_ADD) |
| entry = audit_rule_to_entry(data); |
| else |
| entry = audit_data_to_entry(data, datasz); |
| if (IS_ERR(entry)) |
| return PTR_ERR(entry); |
| |
| err = audit_add_rule(entry); |
| audit_log_rule_change(loginuid, sessionid, sid, "add rule", |
| &entry->rule, !err); |
| |
| if (err) |
| audit_free_rule(entry); |
| break; |
| case AUDIT_DEL: |
| case AUDIT_DEL_RULE: |
| if (type == AUDIT_DEL) |
| entry = audit_rule_to_entry(data); |
| else |
| entry = audit_data_to_entry(data, datasz); |
| if (IS_ERR(entry)) |
| return PTR_ERR(entry); |
| |
| err = audit_del_rule(entry); |
| audit_log_rule_change(loginuid, sessionid, sid, "remove rule", |
| &entry->rule, !err); |
| |
| audit_free_rule(entry); |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| return err; |
| } |
| |
| int audit_comparator(u32 left, u32 op, u32 right) |
| { |
| switch (op) { |
| case Audit_equal: |
| return (left == right); |
| case Audit_not_equal: |
| return (left != right); |
| case Audit_lt: |
| return (left < right); |
| case Audit_le: |
| return (left <= right); |
| case Audit_gt: |
| return (left > right); |
| case Audit_ge: |
| return (left >= right); |
| case Audit_bitmask: |
| return (left & right); |
| case Audit_bittest: |
| return ((left & right) == right); |
| default: |
| BUG(); |
| return 0; |
| } |
| } |
| |
| /* Compare given dentry name with last component in given path, |
| * return of 0 indicates a match. */ |
| int audit_compare_dname_path(const char *dname, const char *path, |
| int *dirlen) |
| { |
| int dlen, plen; |
| const char *p; |
| |
| if (!dname || !path) |
| return 1; |
| |
| dlen = strlen(dname); |
| plen = strlen(path); |
| if (plen < dlen) |
| return 1; |
| |
| /* disregard trailing slashes */ |
| p = path + plen - 1; |
| while ((*p == '/') && (p > path)) |
| p--; |
| |
| /* find last path component */ |
| p = p - dlen + 1; |
| if (p < path) |
| return 1; |
| else if (p > path) { |
| if (*--p != '/') |
| return 1; |
| else |
| p++; |
| } |
| |
| /* return length of path's directory component */ |
| if (dirlen) |
| *dirlen = p - path; |
| return strncmp(p, dname, dlen); |
| } |
| |
| static int audit_filter_user_rules(struct netlink_skb_parms *cb, |
| struct audit_krule *rule, |
| enum audit_state *state) |
| { |
| int i; |
| |
| for (i = 0; i < rule->field_count; i++) { |
| struct audit_field *f = &rule->fields[i]; |
| int result = 0; |
| u32 sid; |
| |
| switch (f->type) { |
| case AUDIT_PID: |
| result = audit_comparator(cb->creds.pid, f->op, f->val); |
| break; |
| case AUDIT_UID: |
| result = audit_comparator(cb->creds.uid, f->op, f->val); |
| break; |
| case AUDIT_GID: |
| result = audit_comparator(cb->creds.gid, f->op, f->val); |
| break; |
| case AUDIT_LOGINUID: |
| result = audit_comparator(audit_get_loginuid(current), |
| f->op, f->val); |
| break; |
| case AUDIT_SUBJ_USER: |
| case AUDIT_SUBJ_ROLE: |
| case AUDIT_SUBJ_TYPE: |
| case AUDIT_SUBJ_SEN: |
| case AUDIT_SUBJ_CLR: |
| if (f->lsm_rule) { |
| security_task_getsecid(current, &sid); |
| result = security_audit_rule_match(sid, |
| f->type, |
| f->op, |
| f->lsm_rule, |
| NULL); |
| } |
| break; |
| } |
| |
| if (!result) |
| return 0; |
| } |
| switch (rule->action) { |
| case AUDIT_NEVER: *state = AUDIT_DISABLED; break; |
| case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; |
| } |
| return 1; |
| } |
| |
| int audit_filter_user(struct netlink_skb_parms *cb) |
| { |
| enum audit_state state = AUDIT_DISABLED; |
| struct audit_entry *e; |
| int ret = 1; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { |
| if (audit_filter_user_rules(cb, &e->rule, &state)) { |
| if (state == AUDIT_DISABLED) |
| ret = 0; |
| break; |
| } |
| } |
| rcu_read_unlock(); |
| |
| return ret; /* Audit by default */ |
| } |
| |
| int audit_filter_type(int type) |
| { |
| struct audit_entry *e; |
| int result = 0; |
| |
| rcu_read_lock(); |
| if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) |
| goto unlock_and_return; |
| |
| list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], |
| list) { |
| int i; |
| for (i = 0; i < e->rule.field_count; i++) { |
| struct audit_field *f = &e->rule.fields[i]; |
| if (f->type == AUDIT_MSGTYPE) { |
| result = audit_comparator(type, f->op, f->val); |
| if (!result) |
| break; |
| } |
| } |
| if (result) |
| goto unlock_and_return; |
| } |
| unlock_and_return: |
| rcu_read_unlock(); |
| return result; |
| } |
| |
| static int update_lsm_rule(struct audit_krule *r) |
| { |
| struct audit_entry *entry = container_of(r, struct audit_entry, rule); |
| struct audit_entry *nentry; |
| int err = 0; |
| |
| if (!security_audit_rule_known(r)) |
| return 0; |
| |
| nentry = audit_dupe_rule(r); |
| if (IS_ERR(nentry)) { |
| /* save the first error encountered for the |
| * return value */ |
| err = PTR_ERR(nentry); |
| audit_panic("error updating LSM filters"); |
| if (r->watch) |
| list_del(&r->rlist); |
| list_del_rcu(&entry->list); |
| list_del(&r->list); |
| } else { |
| if (r->watch || r->tree) |
| list_replace_init(&r->rlist, &nentry->rule.rlist); |
| list_replace_rcu(&entry->list, &nentry->list); |
| list_replace(&r->list, &nentry->rule.list); |
| } |
| call_rcu(&entry->rcu, audit_free_rule_rcu); |
| |
| return err; |
| } |
| |
| /* This function will re-initialize the lsm_rule field of all applicable rules. |
| * It will traverse the filter lists serarching for rules that contain LSM |
| * specific filter fields. When such a rule is found, it is copied, the |
| * LSM field is re-initialized, and the old rule is replaced with the |
| * updated rule. */ |
| int audit_update_lsm_rules(void) |
| { |
| struct audit_krule *r, *n; |
| int i, err = 0; |
| |
| /* audit_filter_mutex synchronizes the writers */ |
| mutex_lock(&audit_filter_mutex); |
| |
| for (i = 0; i < AUDIT_NR_FILTERS; i++) { |
| list_for_each_entry_safe(r, n, &audit_rules_list[i], list) { |
| int res = update_lsm_rule(r); |
| if (!err) |
| err = res; |
| } |
| } |
| mutex_unlock(&audit_filter_mutex); |
| |
| return err; |
| } |