Patchwork [2/2] Bluetooth: check the buffer size for some messages before parsing

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Submitter Greg Kroah-Hartman
Date Jan. 10, 2019, 6:29 a.m.
Message ID <20190110062917.GB15047@kroah.com>
Download mbox | patch
Permalink /patch/696371/
State New
Headers show

Comments

Greg Kroah-Hartman - Jan. 10, 2019, 6:29 a.m.
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@karambasecurity.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/bluetooth/l2cap_core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
Greg Kroah-Hartman - Jan. 10, 2019, 6:30 a.m.
On Thu, Jan 10, 2019 at 07:29:17AM +0100, Greg Kroah-Hartman wrote:
> 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.

Ran, can you verify if these two patches solve the problems you reported
or not?

thanks,

greg k-h

Patch

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 &&