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authorEric Dumazet <edumazet@google.com>2016-11-02 07:53:17 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-21 10:06:39 +0100
commit69a5c7ca2e62072bcf2de664fdf038b64133d5d5 (patch)
treefb5aa0152f5db1051c15d48a6c29792d9b178c37
parent8777977b22c47c47873bdf9e88aa20cc701257bd (diff)
tcp: fix potential memory corruption
[ Upstream commit ac9e70b17ecd7c6e933ff2eaf7ab37429e71bf4d ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/tcp.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 036a76ba2ac2..69daa81736f6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1212,7 +1212,7 @@ new_segment:
if (!skb_can_coalesce(skb, i, pfrag->page,
pfrag->offset)) {
- if (i == sysctl_max_skb_frags || !sg) {
+ if (i >= sysctl_max_skb_frags || !sg) {
tcp_mark_push(tp, skb);
goto new_segment;
}