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authorEric Dumazet <edumazet@google.com>2016-10-20 09:39:40 -0700
committerDavid S. Miller <davem@davemloft.net>2016-10-20 14:45:52 -0400
commit286c72deabaa240b7eebbd99496ed3324d69f3c0 (patch)
tree00a0b07bfc20b08a025720c4c1b3c724ed4eaf67 /net/ipv4
parent2399d6143f85b155ae84ccd94237befd36b8f6c7 (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')
-rw-r--r--net/ipv4/ping.c2
-rw-r--r--net/ipv4/raw.c2
-rw-r--r--net/ipv4/udp.c13
3 files changed, 13 insertions, 4 deletions
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 7cf7d6e380c2..205e2000d395 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -994,7 +994,7 @@ struct proto ping_prot = {
.init = ping_init_sock,
.close = ping_close,
.connect = ip4_datagram_connect,
- .disconnect = udp_disconnect,
+ .disconnect = __udp_disconnect,
.setsockopt = ip_setsockopt,
.getsockopt = ip_getsockopt,
.sendmsg = ping_v4_sendmsg,
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 90a85c955872..ecbe5a7c2d6d 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -918,7 +918,7 @@ struct proto raw_prot = {
.close = raw_close,
.destroy = raw_destroy,
.connect = ip4_datagram_connect,
- .disconnect = udp_disconnect,
+ .disconnect = __udp_disconnect,
.ioctl = raw_ioctl,
.init = raw_init,
.setsockopt = raw_setsockopt,
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);