From b847425fb436aca533a769cc15b4fa11d95177ee Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Fri, 24 Jun 2011 08:38:05 -0400 Subject: [PATCH] Bluetooth: Prevent buffer overflow in l2cap config request commit 7ac28817536797fd40e9646452183606f9e17f71 upstream. A remote user can provide a small value for the command size field in the command header of an l2cap configuration request, resulting in an integer underflow when subtracting the size of the configuration request header. This results in copying a very large amount of data via memcpy() and destroying the kernel heap. Check for underflow. Signed-off-by: Dan Rosenberg Signed-off-by: Gustavo F. Padovan Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/l2cap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index e6859fea515..96b5f42c740 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -2741,7 +2741,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr /* Reject if config buffer is too small. */ len = cmd_len - sizeof(*req); - if (l2cap_pi(sk)->conf_len + len > sizeof(l2cap_pi(sk)->conf_req)) { + if (len < 0 || l2cap_pi(sk)->conf_len + len > sizeof(l2cap_pi(sk)->conf_req)) { l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP, l2cap_build_conf_rsp(sk, rsp, L2CAP_CONF_REJECT, flags), rsp); -- 2.34.1