diff options
| author |   Iván Ezequiel Rodriguez <ivanrwcm25@gmail.com> | 2026-09-01 10:06:28 -0300 |
|---|---|---|
| committer |   Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2026-09-01 07:38:07 -0700 |
| commit | f84819ef8d66931ee3998fee3c4f03230f4cb6cc (patch) | |
| tree | 771c9f48c51777e5db335abfb02954d5d8c23fd4 | |
| parent | Input: evdev - zero absinfo before partial copy in EVIOCSABS (diff) | |
Input: zero ff_effect before compat copy in input_ff_effect_from_user
In the compat path input_ff_effect_from_user() aliases the caller's
native struct ff_effect with the smaller struct ff_effect_compat and
copies only the compat sized prefix:
compat_effect = (struct ff_effect_compat *)effect;
if (copy_from_user(compat_effect, buffer,
sizeof(struct ff_effect_compat)))
The tail of the native structure is never written. Callers pass an
uninitialized on-stack object, for example evdev_do_ioctl() for
EVIOCSFF, so those bytes keep their previous stack contents.
input_ff_upload() then stores the full native structure in
ff->effects[id], from where a uinput based force feedback daemon can
read it back via UI_BEGIN_FF_UPLOAD, disclosing kernel stack memory to
userspace.
Zero the effect before the compat copy.
Fixes: 2d56f3a32c0e ("Input: refactor evdev 32bit compat to be shareable with uinput")
Cc: stable@vger.kernel.org
Signed-off-by: Iván Ezequiel Rodriguez <ivanrwcm25@gmail.com>
Link: https://patch.msgid.link/20260901130629.24078-3-ivanrwcm25@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| -rw-r--r-- | drivers/input/input-compat.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c index a5043193ead8..8860a0730294 100644 --- a/drivers/input/input-compat.c +++ b/drivers/input/input-compat.c @@ -76,6 +76,8 @@ int input_ff_effect_from_user(const char __user *buffer, size_t size, */ compat_effect = (struct ff_effect_compat *)effect; + memset(effect, 0, sizeof(*effect)); + if (copy_from_user(compat_effect, buffer, sizeof(struct ff_effect_compat))) return -EFAULT; |