diff options
| author | Berk Cem Goksel <berkcgoksel@gmail.com> | 2026-03-29 16:38:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-11 14:29:40 +0200 |
| commit | 7594a6464873d90fd229e5b94cdd3b92c9feabed (patch) | |
| tree | 7450dd89d798c076df9547280223d51e8a858a55 | |
| parent | c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54 (diff) | |
ALSA: caiaq: fix stack out-of-bounds read in init_card
commit 45424e871abf2a152e247a9cff78359f18dd95c0 upstream.
The loop creates a whitespace-stripped copy of the card shortname
where `len < sizeof(card->id)` is used for the bounds check. Since
sizeof(card->id) is 16 and the local id buffer is also 16 bytes,
writing 16 non-space characters fills the entire buffer,
overwriting the terminating nullbyte.
When this non-null-terminated string is later passed to
snd_card_set_id() -> copy_valid_id_string(), the function scans
forward with `while (*nid && ...)` and reads past the end of the
stack buffer, reading the contents of the stack.
A USB device with a product name containing many non-ASCII, non-space
characters (e.g. multibyte UTF-8) will reliably trigger this as follows:
BUG: KASAN: stack-out-of-bounds in copy_valid_id_string
sound/core/init.c:696 [inline]
BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c
sound/core/init.c:718
The off-by-one has been present since commit bafeee5b1f8d ("ALSA:
snd_usb_caiaq: give better shortname") from June 2009 (v2.6.31-rc1),
which first introduced this whitespace-stripping loop. The original
code never accounted for the null terminator when bounding the copy.
Fix this by changing the loop bound to `sizeof(card->id) - 1`,
ensuring at least one byte remains as the null terminator.
Fixes: bafeee5b1f8d ("ALSA: snd_usb_caiaq: give better shortname")
Cc: stable@vger.kernel.org
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Berk Cem Goksel <berkcgoksel@gmail.com>
Signed-off-by: Berk Cem Goksel <berkcgoksel@gmail.com>
Link: https://patch.msgid.link/20260329133825.581585-1-berkcgoksel@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/usb/caiaq/device.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c index dfd820483849..3a71bab8a477 100644 --- a/sound/usb/caiaq/device.c +++ b/sound/usb/caiaq/device.c @@ -488,7 +488,7 @@ static int init_card(struct snd_usb_caiaqdev *cdev) memset(id, 0, sizeof(id)); for (c = card->shortname, len = 0; - *c && len < sizeof(card->id); c++) + *c && len < sizeof(card->id) - 1; c++) if (*c != ' ') id[len++] = *c; |