CVE-2026-72487: PCI: Check ROM header and data structure addr before accessing

CVE-2026-72487: PCI: Check ROM header and data structure addr before accessing

[Greg Kroah-Hartman]

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

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

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

PCI: Check ROM header and data structure addr before accessing

We meet a crash when running stress-ng on x86_64 machine:

  BUG: unable to handle page fault for address: ffa0000007f40000
  RIP: 0010:pci_get_rom_size+0x52/0x220
  Call Trace:
  <TASK>
    pci_map_rom+0x80/0x130
    pci_read_rom+0x4b/0xe0
    kernfs_file_read_iter+0x96/0x180
    vfs_read+0x1b1/0x300

Our analysis reveals that the ROM space's start address is
0xffa0000007f30000, and size is 0x10000. Because of broken ROM space,
before calling readl(pds), the pds's value is 0xffa0000007f3ffff, which is
already pointed to the ROM space end, invoking readl() would read 4 bytes
therefore cause an out-of-bounds access and trigger a crash.  Fix this by
adding image header and data structure checking.

We also found another crash on arm64 machine:

  Unable to handle kernel paging request at virtual address ffff8000dd1393ff
  Mem abort info:
  ESR = 0x0000000096000021
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x21: alignment fault

The call trace is the same with x86_64, but the crash reason is that the
data structure addr is not aligned with 4, and arm64 machine report
"alignment fault". Fix this by adding alignment checking.

[bhelgaas: shorten function names, wrap comments]

The Linux kernel CVE team has assigned CVE-2026-72487 to this issue.


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

	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 6.1.178 with commit cd5b242d5848369b9e957340a7e30adee7b6763d
	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 6.6.145 with commit 4997873e3abbad47a9e1e4abd05f045f77a74f22
	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 6.12.97 with commit 724042f8f98d2594b9d164549fd4292c6bd58120
	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 6.18.40 with commit 1d495446ec7ace5b61da366ffb161ee8319dd9a2
	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 7.1.5 with commit 721ad5b72448b5065ed309017ab563205f162404
	Issue introduced in 4.5 with commit 47b975d234eac39f3a72e5496d5f6158d8b806d1 and fixed in 7.2-rc1 with commit 538796b807fcfb81b2ce40cc97a614fd8588feb5

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-2026-72487
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/pci/rom.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/cd5b242d5848369b9e957340a7e30adee7b6763d
	https://git.kernel.org/stable/c/4997873e3abbad47a9e1e4abd05f045f77a74f22
	https://git.kernel.org/stable/c/724042f8f98d2594b9d164549fd4292c6bd58120
	https://git.kernel.org/stable/c/1d495446ec7ace5b61da366ffb161ee8319dd9a2
	https://git.kernel.org/stable/c/721ad5b72448b5065ed309017ab563205f162404
	https://git.kernel.org/stable/c/538796b807fcfb81b2ce40cc97a614fd8588feb5