From: Vlad Yasevich <vladislav.yasevich@hp.com>
Date: Wed, 27 Aug 2008 23:08:54 +0000 (-0700)
Subject: sctp: correct bounds check in sctp_setsockopt_auth_key
X-Git-Tag: v2.6.27-rc5~8^2~1
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=328fc47ea0bcc27d9afa69c3ad6e52431cadd76c;p=linux-2.6

sctp: correct bounds check in sctp_setsockopt_auth_key

The bonds check to prevent buffer overlflow was not exactly
right.  It still allowed overflow of up to 8 bytes which is
sizeof(struct sctp_authkey).

Since optlen is already checked against the size of that struct,
we are guaranteed not to cause interger overflow either.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index afa952e726..9b9b2c31dd 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3144,7 +3144,7 @@ static int sctp_setsockopt_auth_key(struct sock *sk,
 		goto out;
 	}
 
-	if (authkey->sca_keylength > optlen) {
+	if (authkey->sca_keylength > optlen - sizeof(struct sctp_authkey)) {
 		ret = -EINVAL;
 		goto out;
 	}