tcp: fix potential memory corruption
authorEric Dumazet <edumazet@google.com>
Wed, 2 Nov 2016 14:53:17 +0000 (07:53 -0700)
committerDavid S. Miller <davem@davemloft.net>
Thu, 3 Nov 2016 19:33:30 +0000 (15:33 -0400)
commitac9e70b17ecd7c6e933ff2eaf7ab37429e71bf4d
tree781677be717b11066e303449ee4abd787048816e
parent9512925a2cc2b1cd0206bb93bad200a69716f998
tcp: fix potential memory corruption

Imagine initial value of max_skb_frags is 17, and last
skb in write queue has 15 frags.

Then max_skb_frags is lowered to 14 or smaller value.

tcp_sendmsg() will then be allowed to add additional page frags
and eventually go past MAX_SKB_FRAGS, overflowing struct
skb_shared_info.

Fixes: 5f74f82ea34c ("net:Add sysctl_max_skb_frags")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
Cc: HÃ¥kon Bugge <haakon.bugge@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp.c