From 7ac28817536797fd40e9646452183606f9e17f71 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 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(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 56fdd9162da9..7d8a66b04f50 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -2334,7 +2334,7 @@ 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);