linux-kernel - [ 35/95] dccp: check ccid before dereferencing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 09 Sep 2012 23:42:25 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Mathias Krause <minipli@...glemail.com>,
	Gerrit Renker <gerrit@....abdn.ac.uk>,
	"David S. Miller" <davem@...emloft.net>
Subject: [ 35/95] dccp: check ccid before dereferencing

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli@...glemail.com>

commit 276bdb82dedb290511467a5a4fdbe9f0b52dce6f upstream.

ccid_hc_rx_getsockopt() and ccid_hc_tx_getsockopt() might be called with
a NULL ccid pointer leading to a NULL pointer dereference. This could
lead to a privilege escalation if the attacker is able to map page 0 and
prepare it with a fake ccid_ops pointer.

Signed-off-by: Mathias Krause <minipli@...glemail.com>
Cc: Gerrit Renker <gerrit@....abdn.ac.uk>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 net/dccp/ccid.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index 75c3582..fb85d37 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -246,7 +246,7 @@ static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
 					u32 __user *optval, int __user *optlen)
 {
 	int rc = -ENOPROTOOPT;
-	if (ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
+	if (ccid != NULL && ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
 		rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
 						 optval, optlen);
 	return rc;
@@ -257,7 +257,7 @@ static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
 					u32 __user *optval, int __user *optlen)
 {
 	int rc = -ENOPROTOOPT;
-	if (ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
+	if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
 		rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
 						 optval, optlen);
 	return rc;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/