Patchwork HID: i2c-hid: allocate hid buffers for real worst case

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Submitter Dmitry Torokhov
Date Sept. 8, 2017, 5:55 p.m.
Message ID <20170908175527.GA19720@dtor-ws>
Download mbox | patch
Permalink /patch/9944793/
State New
Headers show

Comments

Dmitry Torokhov - Sept. 8, 2017, 5:55 p.m.
From: Adrian Salido <salidoa@google.com>

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(-)
Jiri Kosina - Sept. 13, 2017, 2:02 p.m.
On Fri, 8 Sep 2017, Dmitry Torokhov wrote:

> From: Adrian Salido <salidoa@google.com>
> 
> 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,
Dmitry Torokhov - Sept. 13, 2017, 2:49 p.m.
On Wed, Sep 13, 2017 at 07:02:05AM -0700, Jiri Kosina wrote:
> On Fri, 8 Sep 2017, Dmitry Torokhov wrote:
> 
> > From: Adrian Salido <salidoa@google.com>
> > 
> > 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.
Jiri Kosina - Sept. 13, 2017, 2:52 p.m.
On Wed, 13 Sep 2017, Dmitry Torokhov wrote:

> > > From: Adrian Salido <salidoa@google.com>
> > > 
> > > 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 <bleung@chromium.org>

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

> > Also, I think this should have Cc: stable, right?
> 
> I usually let maintainers decide, but yes.

I'll be adding it. Thanks,
Benson Leung - Sept. 13, 2017, 3 p.m.
Hi Jiri,

On Wed, Sep 13, 2017 at 07:52:20AM -0700, Jiri Kosina wrote:
> > 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 <bleung@chromium.org>
> 
> 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
Jiri Kosina - Sept. 13, 2017, 4:18 p.m.
On Fri, 8 Sep 2017, Dmitry Torokhov wrote:

> From: Adrian Salido <salidoa@google.com>
> 
> 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

Patch

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 */