diff options
| author | Eric Dumazet <edumazet@google.com> | 2016-10-20 09:39:40 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-20 14:45:52 -0400 |
| commit | 286c72deabaa240b7eebbd99496ed3324d69f3c0 (patch) | |
| tree | 00a0b07bfc20b08a025720c4c1b3c724ed4eaf67 /net/ipv4/udp.c | |
| parent | 2399d6143f85b155ae84ccd94237befd36b8f6c7 (diff) | |
udp: must lock the socket in udp_disconnect()
Baozeng Ding reported KASAN traces showing uses after free in
udp_lib_get_port() and other related UDP functions.
A CONFIG_DEBUG_PAGEALLOC=y kernel would eventually crash.
I could write a reproducer with two threads doing :
static int sock_fd;
static void *thr1(void *arg)
{
for (;;) {
connect(sock_fd, (const struct sockaddr *)arg,
sizeof(struct sockaddr_in));
}
}
static void *thr2(void *arg)
{
struct sockaddr_in unspec;
for (;;) {
memset(&unspec, 0, sizeof(unspec));
connect(sock_fd, (const struct sockaddr *)&unspec,
sizeof(unspec));
}
}
Problem is that udp_disconnect() could run without holding socket lock,
and this was causing list corruptions.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp.c')
| -rw-r--r-- | net/ipv4/udp.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 7d96dc2d3d08..311613e413cb 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1345,7 +1345,7 @@ csum_copy_err: goto try_again; } -int udp_disconnect(struct sock *sk, int flags) +int __udp_disconnect(struct sock *sk, int flags) { struct inet_sock *inet = inet_sk(sk); /* @@ -1367,6 +1367,15 @@ int udp_disconnect(struct sock *sk, int flags) sk_dst_reset(sk); return 0; } +EXPORT_SYMBOL(__udp_disconnect); + +int udp_disconnect(struct sock *sk, int flags) +{ + lock_sock(sk); + __udp_disconnect(sk, flags); + release_sock(sk); + return 0; +} EXPORT_SYMBOL(udp_disconnect); void udp_lib_unhash(struct sock *sk) @@ -2193,7 +2202,7 @@ int udp_abort(struct sock *sk, int err) sk->sk_err = err; sk->sk_error_report(sk); - udp_disconnect(sk, 0); + __udp_disconnect(sk, 0); release_sock(sk); |