Re: [PATCH v3 0/4] HID: Proper fix for OOM in hid-core

[Jiri Kosina]

On Mon, 4 May 2026, Benjamin Tissoires wrote:

> Commit 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing
> bogus memset()") enforced the provided data to be at least the size of
> the declared buffer in the report descriptor to prevent a buffer
> overflow.
> 
> We only had corner cases of malicious devices exposing the OOM because
> in most cases, the buffer provided by the transport layer needs to be
> allocated at probe time and is large enough to handle all the possible
> reports.
> 
> However, the patch from above, which enforces the spec a little bit more
> introduced both regressions for devices not following the spec (not
> necesserally malicious), but also a stream of errors for those devices.
> 
> Let's revert to the old behavior by giving more information to HID core
> to be able to decide whether it can or not memset the rest of the buffer
> to 0 and continue the processing.
> 
> Note that the first commit makes an API change, but the callers are
> relatively limited, so it should be fine on its own. The second patch
> can't really make the same kind of API change because we have too many
> callers in various subsystems. We can switch them one by one to the safe
> approach when needed.
> 
> The last 2 patches are small cleanups I initially put together with the
> 2 first patches, but they can be applied on their own and don't need to
> be pulled in stable like the first 2.
> 
> Cheers,
> Benjamin
> 
> Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>

I have now queued the first two in hid.git#for-7.1/upstream-fixes.

I expect the remaining two will be applied once respun with Dmitry's 
suggestion on proper guarding.

Thanks,

-- 
Jiri Kosina
SUSE Labs