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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/raw.c
parent2399d6143f85b155ae84ccd94237befd36b8f6c7 (diff)
downloadlinux-286c72deabaa240b7eebbd99496ed3324d69f3c0.tar.gz
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/raw.c')
-rw-r--r--net/ipv4/raw.c2
1 files changed, 1 insertions, 1 deletions
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,