netdev - [PATCH 2/2] Bluetooth: check the buffer size for some messages before parsing

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Date:   Thu, 10 Jan 2019 07:29:17 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>
Cc:     linux-bluetooth@...r.kernel.org, netdev@...r.kernel.org,
        Ran Menscher <ran.menscher@...ambasecurity.com>
Subject: [PATCH 2/2] Bluetooth: check the buffer size for some messages
 before parsing

The L2CAP_CONF_EFS and L2CAP_CONF_RFC messages can be sent from
userspace so their structure sizes need to be checked before parsing
them.

Based on a patch from Ran Menscher.

Reported-by: Ran Menscher <ran.menscher@...ambasecurity.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/bluetooth/l2cap_core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 93daf94565cf..55e48e6efc2b 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -3361,7 +3361,8 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
 			break;
 
 		case L2CAP_CONF_RFC:
-			if (olen == sizeof(rfc))
+			if ((olen == sizeof(rfc)) &&
+			    (endptr - ptr >= L2CAP_CONF_OPT_SIZE + sizeof(rfc)))
 				memcpy(&rfc, (void *) val, olen);
 			break;
 
@@ -3371,7 +3372,8 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data
 			break;
 
 		case L2CAP_CONF_EFS:
-			if (olen == sizeof(efs)) {
+			if ((olen == sizeof(efs)) &&
+			    (endptr - ptr >= L2CAP_CONF_OPT_SIZE + sizeof(efs))) {
 				remote_efs = 1;
 				memcpy(&efs, (void *) val, olen);
 			}
@@ -3576,7 +3578,8 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
 			break;
 
 		case L2CAP_CONF_RFC:
-			if (olen == sizeof(rfc))
+			if ((olen == sizeof(rfc)) &&
+			    (endptr - ptr >= L2CAP_CONF_OPT_SIZE + sizeof(rfc)))
 				memcpy(&rfc, (void *)val, olen);
 
 			if (test_bit(CONF_STATE2_DEVICE, &chan->conf_state) &&
@@ -3596,7 +3599,8 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
 			break;
 
 		case L2CAP_CONF_EFS:
-			if (olen == sizeof(efs)) {
+			if ((olen == sizeof(efs)) &&
+			    (endptr - ptr >= L2CAP_CONF_OPT_SIZE + sizeof(efs))) {
 				memcpy(&efs, (void *)val, olen);
 
 				if (chan->local_stype != L2CAP_SERV_NOTRAFIC &&
-- 
2.20.1