Message-ID: <2025081906-CVE-2025-38558-86a7@gregkh>
Date: Tue, 19 Aug 2025 19:18:05 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38558: usb: gadget: uvc: Initialize frame-based format color matching descriptor

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: uvc: Initialize frame-based format color matching descriptor

Fix NULL pointer crash in uvcg_framebased_make due to uninitialized color
matching descriptor for frame-based format which was added in
commit f5e7bdd34aca ("usb: gadget: uvc: Allow creating new color matching
descriptors") that added handling for uncompressed and mjpeg format.

Crash is seen when userspace configuration (via configfs) does not
explicitly define the color matching descriptor. If color_matching is not
found, config_group_find_item() returns NULL. The code then jumps to
out_put_cm, where it calls config_item_put(color_matching);. If
color_matching is NULL, this will dereference a null pointer, leading to a
crash.

[    2.746440] Unable to handle kernel NULL pointer dereference at virtual address 000000000000008c
[    2.756273] Mem abort info:
[    2.760080]   ESR = 0x0000000096000005
[    2.764872]   EC = 0x25: DABT (current EL), IL = 32 bits
[    2.771068]   SET = 0, FnV = 0
[    2.771069]   EA = 0, S1PTW = 0
[    2.771070]   FSC = 0x05: level 1 translation fault
[    2.771071] Data abort info:
[    2.771072]   ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
[    2.771073]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    2.771074]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    2.771075] user pgtable: 4k pages, 39-bit VAs, pgdp=00000000a3e59000
[    2.771077] [000000000000008c] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
[    2.771081] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
[    2.771084] Dumping ftrace buffer:
[    2.771085]    (ftrace buffer empty)
[    2.771138] CPU: 7 PID: 486 Comm: ln Tainted: G        W   E      6.6.58-android15
[    2.771139] Hardware name: Qualcomm Technologies, Inc. SunP QRD HDK (DT)
[    2.771140] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    2.771141] pc : __uvcg_fill_strm+0x198/0x2cc
[    2.771145] lr : __uvcg_iter_strm_cls+0xc8/0x17c
[    2.771146] sp : ffffffc08140bbb0
[    2.771146] x29: ffffffc08140bbb0 x28: ffffff803bc81380 x27: ffffff8023bbd250
[    2.771147] x26: ffffff8023bbd250 x25: ffffff803c361348 x24: ffffff803d8e6768
[    2.771148] x23: 0000000000000004 x22: 0000000000000003 x21: ffffffc08140bc48
[    2.771149] x20: 0000000000000000 x19: ffffffc08140bc48 x18: ffffffe9f8cf4a00
[    2.771150] x17: 000000001bf64ec3 x16: 000000001bf64ec3 x15: ffffff8023bbd250
[    2.771151] x14: 000000000000000f x13: 004c4b40000f4240 x12: 000a2c2a00051615
[    2.771152] x11: 000000000000004f x10: ffffffe9f76b40ec x9 : ffffffe9f7e389d0
[    2.771153] x8 : ffffff803d0d31ce x7 : 000f4240000a2c2a x6 : 0005161500028b0a
[    2.771154] x5 : ffffff803d0d31ce x4 : 0000000000000003 x3 : 0000000000000000
[    2.771155] x2 : ffffffc08140bc50 x1 : ffffffc08140bc48 x0 : 0000000000000000
[    2.771156] Call trace:
[    2.771157]  __uvcg_fill_strm+0x198/0x2cc
[    2.771157]  __uvcg_iter_strm_cls+0xc8/0x17c
[    2.771158]  uvcg_streaming_class_allow_link+0x240/0x290
[    2.771159]  configfs_symlink+0x1f8/0x630
[    2.771161]  vfs_symlink+0x114/0x1a0
[    2.771163]  do_symlinkat+0x94/0x28c
[    2.771164]  __arm64_sys_symlinkat+0x54/0x70
[    2.771164]  invoke_syscall+0x58/0x114
[    2.771166]  el0_svc_common+0x80/0xe0
[    2.771168]  do_el0_svc+0x1c/0x28
[    2.771169]  el0_svc+0x3c/0x70
[    2.771172]  el0t_64_sync_handler+0x68/0xbc
[    2.771173]  el0t_64_sync+0x1a8/0x1ac

Initialize color matching descriptor for frame-based format to prevent
NULL pointer crash by mirroring the handling done for uncompressed and
mjpeg formats.

The Linux kernel CVE team has assigned CVE-2025-38558 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.13 with commit 7b5a58952fc3b51905c2963647485565df1e5e26 and fixed in 6.15.10 with commit 6db61c1aa23075eeee90e083ca3f6567a5635da6
	Issue introduced in 6.13 with commit 7b5a58952fc3b51905c2963647485565df1e5e26 and fixed in 6.16.1 with commit 7f8576fc9d1a203d12474bf52710c7af68cae490
	Issue introduced in 6.13 with commit 7b5a58952fc3b51905c2963647485565df1e5e26 and fixed in 6.17-rc1 with commit 323a80a1a5ace319a722909c006d5bdb2a35d273

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-38558
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/usb/gadget/function/uvc_configfs.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/6db61c1aa23075eeee90e083ca3f6567a5635da6
	https://git.kernel.org/stable/c/7f8576fc9d1a203d12474bf52710c7af68cae490
	https://git.kernel.org/stable/c/323a80a1a5ace319a722909c006d5bdb2a35d273

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