From: Dave Stevenson Date: Fri, 10 Mar 2017 14:43:15 +0000 (+0000) Subject: bcm2835-v4l2: Fix buffer overflow problem X-Git-Tag: archive/raspbian/4.9.82-1+deb9u3+rpi1_jessie~5^2~288 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=0798a364c331378ce6b37d6d4c276040505a5417;p=linux-4.9.git bcm2835-v4l2: Fix buffer overflow problem https://github.com/raspberrypi/linux/issues/1447 port_parameter_get() failed to account for the header (u32 id and u32 size) in the size before memcpying the response into the response buffer, so overrunning the provided buffer by 8 bytes. Account for those bytes, and also a belt-and-braces check to ensure we never copy more than *value_size bytes into value. Signed-off-by: Dave Stevenson --- diff --git a/drivers/media/platform/bcm2835/mmal-vchiq.c b/drivers/media/platform/bcm2835/mmal-vchiq.c index 781322542d5a..e4b243b33f58 100644 --- a/drivers/media/platform/bcm2835/mmal-vchiq.c +++ b/drivers/media/platform/bcm2835/mmal-vchiq.c @@ -1315,7 +1315,12 @@ static int port_parameter_get(struct vchiq_mmal_instance *instance, } ret = -rmsg->u.port_parameter_get_reply.status; - if (ret) { + /* port_parameter_get_reply.size includes the header, + * whilst *value_size doesn't. + */ + rmsg->u.port_parameter_get_reply.size -= (2 * sizeof(u32)); + + if (ret || rmsg->u.port_parameter_get_reply.size > *value_size) { /* Copy only as much as we have space for * but report true size of parameter */