From 276bdb82dedb290511467a5a4fdbe9f0b52dce6f Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Wed, 15 Aug 2012 11:31:54 +0000 Subject: [PATCH] dccp: check ccid before dereferencing 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 Cc: Gerrit Renker Cc: stable@vger.kernel.org Signed-off-by: David S. Miller --- 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 75c3582a7678..fb85d371a8de 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; -- 2.20.1