tcp repair: Fix unaligned access when repairing options (v2)
Don't pick __u8/__u16 values directly from raw pointers, but instead use
an array of structures of code:value pairs. This is OK, since the buffer
we take options from is not an skb memory, but a user-to-kernel one.
For those options which don't require any value now, require this to be
zero (for potential future extension of this API).
v2: Changed tcp_repair_opt to use two __u32-s as spotted by David Laight.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 9865936..278af9e 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -111,6 +111,11 @@
#define TCP_QUEUE_SEQ 21
#define TCP_REPAIR_OPTIONS 22
+struct tcp_repair_opt {
+ __u32 opt_code;
+ __u32 opt_val;
+};
+
enum {
TCP_NO_QUEUE,
TCP_RECV_QUEUE,
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index de6a238..9670af3 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2283,60 +2283,40 @@
((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_ESTABLISHED));
}
-static int tcp_repair_options_est(struct tcp_sock *tp, char __user *optbuf, unsigned int len)
+static int tcp_repair_options_est(struct tcp_sock *tp,
+ struct tcp_repair_opt __user *optbuf, unsigned int len)
{
- /*
- * Options are stored in CODE:VALUE form where CODE is 8bit and VALUE
- * fits the respective TCPOLEN_ size
- */
+ struct tcp_repair_opt opt;
- while (len > 0) {
- u8 opcode;
-
- if (get_user(opcode, optbuf))
+ while (len >= sizeof(opt)) {
+ if (copy_from_user(&opt, optbuf, sizeof(opt)))
return -EFAULT;
optbuf++;
- len--;
+ len -= sizeof(opt);
- switch (opcode) {
- case TCPOPT_MSS: {
- u16 in_mss;
-
- if (len < sizeof(in_mss))
- return -ENODATA;
- if (get_user(in_mss, optbuf))
- return -EFAULT;
-
- tp->rx_opt.mss_clamp = in_mss;
-
- optbuf += sizeof(in_mss);
- len -= sizeof(in_mss);
+ switch (opt.opt_code) {
+ case TCPOPT_MSS:
+ tp->rx_opt.mss_clamp = opt.opt_val;
break;
- }
- case TCPOPT_WINDOW: {
- u8 wscale;
-
- if (len < sizeof(wscale))
- return -ENODATA;
- if (get_user(wscale, optbuf))
- return -EFAULT;
-
- if (wscale > 14)
+ case TCPOPT_WINDOW:
+ if (opt.opt_val > 14)
return -EFBIG;
- tp->rx_opt.snd_wscale = wscale;
-
- optbuf += sizeof(wscale);
- len -= sizeof(wscale);
+ tp->rx_opt.snd_wscale = opt.opt_val;
break;
- }
case TCPOPT_SACK_PERM:
+ if (opt.opt_val != 0)
+ return -EINVAL;
+
tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
if (sysctl_tcp_fack)
tcp_enable_fack(tp);
break;
case TCPOPT_TIMESTAMP:
+ if (opt.opt_val != 0)
+ return -EINVAL;
+
tp->rx_opt.tstamp_ok = 1;
break;
}
@@ -2557,7 +2537,9 @@
if (!tp->repair)
err = -EINVAL;
else if (sk->sk_state == TCP_ESTABLISHED)
- err = tcp_repair_options_est(tp, optval, optlen);
+ err = tcp_repair_options_est(tp,
+ (struct tcp_repair_opt __user *)optval,
+ optlen);
else
err = -EPERM;
break;
