xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

tcp: add rcu protection around tp->fastopen_rsk

Browse Source 
Both tcp_v4_err() and tcp_v6_err() do the following operations
while they do not own the socket lock :

	fastopen = tp->fastopen_rsk;
 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;

The problem is that without appropriate barrier, the compiler
might reload tp->fastopen_rsk and trigger a NULL deref.

request sockets are protected by RCU, we can simply add
the missing annotations and barriers to solve the issue.

Fixes: 168a8f5805 ("tcp: TCP Fast Open Server - main code path")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2019-10-10 20:17:38 -07:00
committed by David S. Miller
parent 8caf8a91f3
commit d983ea6f16
11 changed files with 35 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
net/ipv4/tcp_output.c
View File

@@ -2482,7 +2482,7 @@ bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto)
/* Don't do any loss probe on a Fast Open connection before 3WHS
* finishes.
*/
if (tp->fastopen_rsk)
if (rcu_access_pointer(tp->fastopen_rsk))
return false;
early_retrans = sock_net(sk)->ipv4.sysctl_tcp_early_retrans;