From df0bca049d01c0ee94afb7cd5dfd959541e6c8da Mon Sep 17 00:00:00 2001 From: =?utf8?q?Cl=C3=A9ment=20Lecigne?= Date: Thu, 12 Feb 2009 16:59:09 -0800 Subject: [PATCH] net: 4 bytes kernel memory disclosure in SO_BSDCOMPAT gsopt try #2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit In function sock_getsockopt() located in net/core/sock.c, optval v.val is not correctly initialized and directly returned in userland in case we have SO_BSDCOMPAT option set. This dummy code should trigger the bug: int main(void) { unsigned char buf[4] = { 0, 0, 0, 0 }; int len; int sock; sock = socket(33, 2, 2); getsockopt(sock, 1, SO_BSDCOMPAT, &buf, &len); printf("%x%x%x%x\n", buf[0], buf[1], buf[2], buf[3]); close(sock); } Here is a patch that fix this bug by initalizing v.val just after its declaration. Signed-off-by: Clément Lecigne Signed-off-by: David S. Miller --- net/core/sock.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/core/sock.c b/net/core/sock.c index f3a0d08cbb48..6f2e1337975d 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -696,6 +696,8 @@ int sock_getsockopt(struct socket *sock, int level, int optname, if (len < 0) return -EINVAL; + v.val = 0; + switch(optname) { case SO_DEBUG: v.val = sock_flag(sk, SOCK_DBG); -- 2.20.1