From 1752e5327a01247d605515dbba86ad32a493db93 Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Fri, 24 Jun 2011 08:38:05 -0400 Subject: Bluetooth: Prevent buffer overflow in l2cap config request 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 Cc: stable Signed-off-by: Gustavo F. Padovan --- net/bluetooth/l2cap_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 9c7bccfcc72..38efc9f32c4 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -2535,7 +2535,7 @@ 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 (chan->conf_len + len > sizeof(chan->conf_req)) { + if (len < 0 || chan->conf_len + len > sizeof(chan->conf_req)) { l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP, l2cap_build_conf_rsp(chan, rsp, L2CAP_CONF_REJECT, flags), rsp); -- cgit v1.2.3