From 286c72deabaa240b7eebbd99496ed3324d69f3c0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 20 Oct 2016 09:39:40 -0700 Subject: 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 Reported-by: Baozeng Ding Signed-off-by: David S. Miller --- net/ipv6/raw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv6/raw.c') diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 54404f08efcc..054a1d84fc5e 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1241,7 +1241,7 @@ struct proto rawv6_prot = { .close = rawv6_close, .destroy = raw6_destroy, .connect = ip6_datagram_connect_v6_only, - .disconnect = udp_disconnect, + .disconnect = __udp_disconnect, .ioctl = rawv6_ioctl, .init = rawv6_init_sk, .setsockopt = rawv6_setsockopt, -- cgit v1.2.3-59-g8ed1b