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 --- include/net/udp.h | 1 + net/ipv4/ping.c | 2 +- net/ipv4/raw.c | 2 +- net/ipv4/udp.c | 13 +++++++++++-- net/ipv6/ping.c | 2 +- net/ipv6/raw.c | 2 +- net/l2tp/l2tp_ip.c | 2 +- net/l2tp/l2tp_ip6.c | 2 +- 8 files changed, 18 insertions(+), 8 deletions(-) diff --git a/include/net/udp.h b/include/net/udp.h index ea53a87d880f..4948790d393d 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -258,6 +258,7 @@ void udp_flush_pending_frames(struct sock *sk); void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst); int udp_rcv(struct sk_buff *skb); int udp_ioctl(struct sock *sk, int cmd, unsigned long arg); +int __udp_disconnect(struct sock *sk, int flags); int udp_disconnect(struct sock *sk, int flags); unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait); struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 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); diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c index 0e983b694ee8..66e2d9dfc43a 100644 --- a/net/ipv6/ping.c +++ b/net/ipv6/ping.c @@ -180,7 +180,7 @@ struct proto pingv6_prot = { .init = ping_init_sock, .close = ping_close, .connect = ip6_datagram_connect_v6_only, - .disconnect = udp_disconnect, + .disconnect = __udp_disconnect, .setsockopt = ipv6_setsockopt, .getsockopt = ipv6_getsockopt, .sendmsg = ping_v6_sendmsg, 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, diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index 42de4ccd159f..fce25afb652a 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -338,7 +338,7 @@ static int l2tp_ip_disconnect(struct sock *sk, int flags) if (sock_flag(sk, SOCK_ZAPPED)) return 0; - return udp_disconnect(sk, flags); + return __udp_disconnect(sk, flags); } static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr, diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index ea2ae6664cc8..ad3468c32b53 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -410,7 +410,7 @@ static int l2tp_ip6_disconnect(struct sock *sk, int flags) if (sock_flag(sk, SOCK_ZAPPED)) return 0; - return udp_disconnect(sk, flags); + return __udp_disconnect(sk, flags); } static int l2tp_ip6_getname(struct socket *sock, struct sockaddr *uaddr, -- cgit v1.2.3-59-g8ed1b