From b20e7bbfc7a15a4182730f0936433145992b4b06 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 21 Mar 2011 18:18:00 -0700 Subject: net/appletalk: fix atalk_release use after free The BKL removal in appletalk introduced a use-after-free problem, where atalk_destroy_socket frees a sock, but we still release the socket lock on it. An easy fix is to take an extra reference on the sock and sock_put it when returning from atalk_release. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller --- net/appletalk/ddp.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/appletalk/ddp.c') diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index 3d4f4b043406..206e771e82d1 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1051,6 +1051,7 @@ static int atalk_release(struct socket *sock) { struct sock *sk = sock->sk; + sock_hold(sk); lock_sock(sk); if (sk) { sock_orphan(sk); @@ -1058,6 +1059,8 @@ static int atalk_release(struct socket *sock) atalk_destroy_socket(sk); } release_sock(sk); + sock_put(sk); + return 0; } -- cgit v1.2.3 From c100c8f4c3c6f2a407bdbaaad2c4f1062e6a473a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 31 Mar 2011 18:59:10 -0700 Subject: appletalk: Fix OOPS in atalk_release(). Commit 60d9f461a20ba59219fdcdc30cbf8e3a4ad3f625 ("appletalk: remove the BKL") added a dereference of "sk" before checking for NULL in atalk_release(). Guard the code block completely, rather than partially, with the NULL check. Reported-by: Dave Jones Signed-off-by: David S. Miller --- net/appletalk/ddp.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'net/appletalk/ddp.c') diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index 206e771e82d1..956a5302002a 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1051,16 +1051,17 @@ static int atalk_release(struct socket *sock) { struct sock *sk = sock->sk; - sock_hold(sk); - lock_sock(sk); if (sk) { + sock_hold(sk); + lock_sock(sk); + sock_orphan(sk); sock->sk = NULL; atalk_destroy_socket(sk); - } - release_sock(sk); - sock_put(sk); + release_sock(sk); + sock_put(sk); + } return 0; } -- cgit v1.2.3