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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2019-12-14 01:56:16 +0300 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2019-12-14 02:00:42 +0300 |
| commit | cb222aed03d798fc074be55e59d9a112338ee784 (patch) | |
| tree | a94ae6b93178d73d0cee45ed20c1a085c17b1f5c /drivers/input | |
| parent | f729a1b0f8df7091cea3729fc0e414f5326e1163 (diff) | |
| download | linux-cb222aed03d798fc074be55e59d9a112338ee784.tar.xz | |
Input: add safety guards to input_set_keycode()
If we happen to have a garbage in input device's keycode table with values
too big we'll end up doing clear_bit() with offset way outside of our
bitmaps, damaging other objects within an input device or even outside of
it. Let's add sanity checks to the returned old keycodes.
Reported-by: syzbot+c769968809f9359b07aa@syzkaller.appspotmail.com
Reported-by: syzbot+76f3a30e88d256644c78@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20191207212757.GA245964@dtor-ws
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input')
| -rw-r--r-- | drivers/input/input.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/input/input.c b/drivers/input/input.c index 55086279d044..ee6c3234df36 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -878,16 +878,18 @@ static int input_default_setkeycode(struct input_dev *dev, } } - __clear_bit(*old_keycode, dev->keybit); - __set_bit(ke->keycode, dev->keybit); - - for (i = 0; i < dev->keycodemax; i++) { - if (input_fetch_keycode(dev, i) == *old_keycode) { - __set_bit(*old_keycode, dev->keybit); - break; /* Setting the bit twice is useless, so break */ + if (*old_keycode <= KEY_MAX) { + __clear_bit(*old_keycode, dev->keybit); + for (i = 0; i < dev->keycodemax; i++) { + if (input_fetch_keycode(dev, i) == *old_keycode) { + __set_bit(*old_keycode, dev->keybit); + /* Setting the bit twice is useless, so break */ + break; + } } } + __set_bit(ke->keycode, dev->keybit); return 0; } @@ -943,9 +945,13 @@ int input_set_keycode(struct input_dev *dev, * Simulate keyup event if keycode is not present * in the keymap anymore */ - if (test_bit(EV_KEY, dev->evbit) && - !is_event_supported(old_keycode, dev->keybit, KEY_MAX) && - __test_and_clear_bit(old_keycode, dev->key)) { + if (old_keycode > KEY_MAX) { + dev_warn(dev->dev.parent ?: &dev->dev, + "%s: got too big old keycode %#x\n", + __func__, old_keycode); + } else if (test_bit(EV_KEY, dev->evbit) && + !is_event_supported(old_keycode, dev->keybit, KEY_MAX) && + __test_and_clear_bit(old_keycode, dev->key)) { struct input_value vals[] = { { EV_KEY, old_keycode, 0 }, input_value_sync |