diff options
| author | subashab@codeaurora.org <subashab@codeaurora.org> | 2015-01-23 22:26:02 +0000 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2016-11-07 13:44:39 +0100 |
| commit | f44b3ed1bd2a6bd3d0178eab39b3ae016b8f51bc (patch) | |
| tree | 28ebd38b81e97590bbfa8af18fd8e9d81fd156ee | |
| parent | 00ec1659292805854bf0870093a74f7559babb69 (diff) | |
ping: Fix race in free in receive path
[ Upstream commit fc752f1f43c1c038a2c6ae58cc739ebb5953ccb0 ]
An exception is seen in ICMP ping receive path where the skb
destructor sock_rfree() tries to access a freed socket. This happens
because ping_rcv() releases socket reference with sock_put() and this
internally frees up the socket. Later icmp_rcv() will try to free the
skb and as part of this, skb destructor is called and which leads
to a kernel panic as the socket is freed already in ping_rcv().
-->|exception
-007|sk_mem_uncharge
-007|sock_rfree
-008|skb_release_head_state
-009|skb_release_all
-009|__kfree_skb
-010|kfree_skb
-011|icmp_rcv
-012|ip_local_deliver_finish
Fix this incorrect free by cloning this skb and processing this cloned
skb instead.
This patch was suggested by Eric Dumazet
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/ping.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index d99c80b5a..0f49b1071 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -257,7 +257,7 @@ int ping_init_sock(struct sock *sk) int i, j, count; kgid_t low, high; int ret = 0; - + inet_get_ping_group_range_net(net, &low, &high); if (gid_lte(low, group) && gid_lte(group, high)) return 0; @@ -966,12 +966,18 @@ void ping_rcv(struct sk_buff *skb) sk = ping_lookup(net, skb, ntohs(icmph->un.echo.id)); if (sk != NULL) { -#ifdef CONFIG_MTK_NET_LOGGING +#ifdef CONFIG_MTK_NET_LOGGING printk(KERN_INFO "[mtk_net][ping_debug]rcv on sk %p\n", sk); #endif ping_queue_rcv_skb(sk, skb_get(skb)); /*mtk_net: don't put sock here, do sock_put after free skb*/ /* sock_put(sk); */ + struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); + + pr_debug("rcv on socket %p\n", sk); + if (skb2) + ping_queue_rcv_skb(sk, skb2); + sock_put(sk); return; } pr_info("[mtk_net][ping_debug]no socket, dropping\n"); |