kernel/linux.git/sound/core/control.c, branch v7.1-rc5

ALSA: control: Validate buf_len before strnlen() in snd_ctl_elem_init_enum_names()

2026-04-14T13:31:10+00:00

snd_ctl_elem_init_enum_names() advances pointer p through the names buffer while decrementing buf_len. If buf_len reaches zero but items remain, the next iteration calls strnlen(p, 0). While strnlen(p, 0) returns 0 and would hit the existing name_len == 0 error path, CONFIG_FORTIFY_SOURCE's fortified strnlen() first checks maxlen against __builtin_dynamic_object_size(). When Clang loses track of p's object size inside the loop, this triggers a BRK exception panic before the return value is examined. Add a buf_len == 0 guard at the loop entry to prevent calling fortified strnlen() on an exhausted buffer. Found by kernel fuzz testing through Xiaomi Smartphone. Fixes: 8d448162bda5 ("ALSA: control: add support for ENUMERATED user space controls") Cc: stable@vger.kernel.org Signed-off-by: Ziqing Chen Link: https://patch.msgid.link/20260414132437.261304-1-chenziqing@xiaomi.com Signed-off-by: Takashi Iwai

ALSA: control: Verify put() result when in debug mode

2026-02-28T08:32:39+00:00

The put() operation is expected to return: 1) 0 on success if no changes were made 2) 1 on success if changes were made 3) error code otherwise Currently 2) is usually ignored when writing control-operations. While forcing compliance is not an option right now, make it easier for developers to adhere to the expectations and notice problems by logging them when CONFIG_SND_CTL_DEBUG is enabled. Due to large size of struct snd_ctl_elem_value, 'value_buf' is provided as a reusable buffer for kctl->put() verification. This prevents exhausting the stack when verifying the operation. >From user perspective, patch introduces a new trace/events category 'snd_ctl' containing a single 'snd_ctl_put' event type. Log sample: amixer-1086 [003] ..... 8.035939: snd_ctl_put: success: expected=0, actual=0 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1087 [003] ..... 8.938721: snd_ctl_put: success: expected=1, actual=1 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1088 [003] ..... 9.631470: snd_ctl_put: success: expected=1, actual=1 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1089 [000] ..... 9.636786: snd_ctl_put: fail: expected=1, actual=0 for ctl numid=5, iface=MIXER, name='Loopback Mute', index=0, device=0, subdevice=0, card=0 Signed-off-by: Cezary Rojewski Reviewed-by: Mark Brown Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20260224205619.584795-1-cezary.rojewski@intel.com

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ALSA: control: Relax __free() variable declarations

2025-12-17T09:08:29+00:00

We used to have a variable declaration with __free() initialized with NULL. This was to keep the old coding style rule, but recently it's relaxed and rather recommends to follow the new rule to declare in place of use for __free() -- which avoids potential deadlocks or UAFs with nested cleanups. Although the current code has no bug, per se, let's follow the new standard and move the declaration to the place of assignment (or directly assign the allocated result) instead of NULL initializations. Fixes: 7dba48a474e6 ("ALSA: control_led: Use guard() for locking") Fixes: 1052d9882269 ("ALSA: control: Use automatic cleanup of kfree()") Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20251216140634.171890-3-tiwai@suse.de

ALSA: control: Use safer strscpy() instead of strcpy()

2025-07-11T07:51:08+00:00

Use a safer function strscpy() instead of strcpy() for copying to arrays. Only idiomatic code replacement, and no functional changes. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20250710100727.22653-2-tiwai@suse.de

ALSA: core: use snd_kcontrol_chip()

2025-05-08T09:53:34+00:00

We can use snd_kcontrol_chip(). Let's use it. Signed-off-by: Kuninori Morimoto Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/87selhaudp.wl-kuninori.morimoto.gx@renesas.com

Merge tag 'asoc-fix-v6.12-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

2024-10-02T19:29:16+00:00

ASoC: Fixes for v6.12 A bunch of fixes here that came in during the merge window and the first week of release, plus some new quirks and device IDs. There's nothing major here, it's a bit bigger than it might've been due to there being no fixes sent during the merge window due to your vacation.

ALSA: silence integer wrapping warning

2024-10-01T12:56:40+00:00

This patch doesn't change runtime at all, it's just for kernel hardening. The "count" here comes from the user and on 32bit systems, it leads to integer wrapping when we pass it to compute_user_elem_size(): alloc_size = compute_user_elem_size(private_size, count); However, the integer over is harmless because later "count" is checked when we pass it to snd_ctl_new(): err = snd_ctl_new(&kctl, count, access, file); These days as part of kernel hardening we're trying to avoid integer overflows when they affect size_t type. So to avoid the integer overflow copy the check from snd_ctl_new() and do it at the start of the snd_ctl_elem_add() function as well. Signed-off-by: Dan Carpenter Reviewed-by: Jaroslav Kysela Link: https://patch.msgid.link/5457e8c1-01ff-4dd9-b49c-15b817f65ee7@stanley.mountain Signed-off-by: Takashi Iwai