HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request

Browse source

As reported by Sashiko:
If a transport driver encounters a hardware error and returns a negative
error code such as -EPIPE, ret is implicitly promoted to size_t when
compared against size. This causes the negative error code to evaluate
as a large positive number, making the (ret > size) condition true.

This silently converts the hardware error into a success return value
and copies the unmodified buffer back, which could leave BPF programs
operating on uninitialized or stale data.

Fix this by casting size into ssize_t to return the actual negative
error code.

Link: https://lore.kernel.org/all/20260904130354.A79471F00A3D@smtp.kernel.org/
Fixes: 2b658c1c44 ("HID: bpf: prevent buffer overflow in hid_hw_request")
Cc: stable@vger.kernel.org
Acked-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

...

This commit is contained in:

Benjamin Tissoires 2026-09-15 17:46:57 +02:00

parent a1cdd72371

commit 3afefbfe55

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

drivers/hid/bpf/hid_bpf_dispatch.c

View file