[PATCH] HID: i2c-hid: allocate hid buffers for real worst case

From: Adrian Salido <redacted>

The buffer allocation is not currently accounting for an extra byte for
the report id. This can cause an out of bounds access in function
i2c_hid_set_or_send_report() with reportID > 15.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/hid/i2c-hid/i2c-hid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 77396145d2d0..9145c2129a96 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c

@@ -543,7 +543,8 @@ static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
 {
 	/* the worst case is computed from the set_report command with a
 	 * reportID > 15 and the maximum report length */
-	int args_len = sizeof(__u8) + /* optional ReportID byte */
+	int args_len = sizeof(__u8) + /* ReportID */
+		       sizeof(__u8) + /* optional ReportID byte */
 		       sizeof(__u16) + /* data register */
 		       sizeof(__u16) + /* size of the report */
 		       report_size; /* report */

-- 
2.14.1.581.gf28d330327-goog


-- 
Dmitry

On Fri, 8 Sep 2017, Dmitry Torokhov wrote:

From: Adrian Salido <redacted>

The buffer allocation is not currently accounting for an extra byte for
the report id. This can cause an out of bounds access in function
i2c_hid_set_or_send_report() with reportID > 15.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Missing signoff from the patch author?

Also, I think this should have Cc: stable, right?

Thanks,

-- 
Jiri Kosina
SUSE Labs

On Wed, Sep 13, 2017 at 07:02:05AM -0700, Jiri Kosina wrote:

On Fri, 8 Sep 2017, Dmitry Torokhov wrote:

quoted

From: Adrian Salido <redacted>

The buffer allocation is not currently accounting for an extra byte for
the report id. This can cause an out of bounds access in function
i2c_hid_set_or_send_report() with reportID > 15.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Missing signoff from the patch author?

Oops, I must have cut it off on accident while removing ChromeOS
specific tags, the original commit is here:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/475212

Also, I think this should have Cc: stable, right?

I usually let maintainers decide, but yes.

Thanks.

-- 
Dmitry

On Wed, 13 Sep 2017, Dmitry Torokhov wrote:

quoted

quoted

From: Adrian Salido <redacted>

The buffer allocation is not currently accounting for an extra byte for
the report id. This can cause an out of bounds access in function
i2c_hid_set_or_send_report() with reportID > 15.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Missing signoff from the patch author?

Oops, I must have cut it off on accident while removing ChromeOS
specific tags, the original commit is here:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/475212

Ok, thanks, will use that one. How about 

	Reviewed-by: Benson Leung [off-list ref]

which is missing in the mail you've sent, but is there in the above 
reference commit?

quoted

Also, I think this should have Cc: stable, right?

I usually let maintainers decide, but yes.

I'll be adding it. Thanks,

-- 
Jiri Kosina
SUSE Labs

Hi Jiri,

On Wed, Sep 13, 2017 at 07:52:20AM -0700, Jiri Kosina wrote:

quoted

Oops, I must have cut it off on accident while removing ChromeOS
specific tags, the original commit is here:

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/475212

Ok, thanks, will use that one. How about 

	Reviewed-by: Benson Leung [off-list ref]

which is missing in the mail you've sent, but is there in the above 
reference commit?

Submission looks good to me. Go ahead and add.
Reviewed-by: Benson Leung <bleung@chromium.org>

Thanks,
Benson
-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@google.com
Chromium OS Project
bleung@chromium.org

On Fri, 8 Sep 2017, Dmitry Torokhov wrote:

From: Adrian Salido <redacted>

The buffer allocation is not currently accounting for an extra byte for
the report id. This can cause an out of bounds access in function
i2c_hid_set_or_send_report() with reportID > 15.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

I've added the missing tags and applied to for-4.14/upstream-fixes

-- 
Jiri Kosina
SUSE Labs