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authorEric Dumazet <edumazet@google.com>2013-02-12 06:16:53 +0000
committerDavid S. Miller <davem@davemloft.net>2013-02-12 16:07:19 -0500
commit77c1090f94d1b0b5186fb13a1b71b47b1343f87f (patch)
tree722dc8535ddfc0cf92f8748d439890a83b6211d3
parent1bf014e5c2d8e62ae11a5a8f70dc679f5d0787eb (diff)
net: fix infinite loop in __skb_recv_datagram()
Tommi was fuzzing with trinity and reported the following problem : commit 3f518bf745 (datagram: Add offset argument to __skb_recv_datagram) missed that a raw socket receive queue can contain skbs with no payload. We can loop in __skb_recv_datagram() with MSG_PEEK mode, because wait_for_packet() is not prepared to skip these skbs. [ 83.541011] INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 0, t=26002 jiffies, g=27673, c=27672, q=75) [ 83.541011] INFO: Stall ended before state dump start [ 108.067010] BUG: soft lockup - CPU#0 stuck for 22s! [trinity-child31:2847] ... [ 108.067010] Call Trace: [ 108.067010] [<ffffffff818cc103>] __skb_recv_datagram+0x1a3/0x3b0 [ 108.067010] [<ffffffff818cc33d>] skb_recv_datagram+0x2d/0x30 [ 108.067010] [<ffffffff819ed43d>] rawv6_recvmsg+0xad/0x240 [ 108.067010] [<ffffffff818c4b04>] sock_common_recvmsg+0x34/0x50 [ 108.067010] [<ffffffff818bc8ec>] sock_recvmsg+0xbc/0xf0 [ 108.067010] [<ffffffff818bf31e>] sys_recvfrom+0xde/0x150 [ 108.067010] [<ffffffff81ca4329>] system_call_fastpath+0x16/0x1b Reported-by: Tommi Rantala <tt.rantala@gmail.com> Tested-by: Tommi Rantala <tt.rantala@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/datagram.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 0337e2b..368f9c3 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -187,7 +187,7 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
skb_queue_walk(queue, skb) {
*peeked = skb->peeked;
if (flags & MSG_PEEK) {
- if (*off >= skb->len) {
+ if (*off >= skb->len && skb->len) {
*off -= skb->len;
continue;
}