linux-cve-announce - CVE-2023-53814: PCI: Fix dropping valid root bus resources with .end = zero

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Message-ID: <2025120945-CVE-2023-53814-eccb@gregkh>
Date: Tue,  9 Dec 2025 09:02:35 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53814: PCI: Fix dropping valid root bus resources with .end = zero

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

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

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

PCI: Fix dropping valid root bus resources with .end = zero

On r8a7791/koelsch:

  kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
  # cat /sys/kernel/debug/kmemleak
  unreferenced object 0xc3a34e00 (size 64):
    comm "swapper/0", pid 1, jiffies 4294937460 (age 199.080s)
    hex dump (first 32 bytes):
      b4 5d 81 f0 b4 5d 81 f0 c0 b0 a2 c3 00 00 00 00  .]...]..........
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<fe3aa979>] __kmalloc+0xf0/0x140
      [<34bd6bc0>] resource_list_create_entry+0x18/0x38
      [<767046bc>] pci_add_resource_offset+0x20/0x68
      [<b3f3edf2>] devm_of_pci_get_host_bridge_resources.constprop.0+0xb0/0x390

When coalescing two resources for a contiguous aperture, the second
resource is enlarged to cover the full contiguous range, while the first
resource is marked invalid.  This invalidation is done by clearing the
flags, start, and end members.

When adding the initial resources to the bus later, invalid resources are
skipped.  Unfortunately, the check for an invalid resource considers only
the end member, causing false positives.

E.g. on r8a7791/koelsch, root bus resource 0 ("bus 00") is skipped, and no
longer registered with pci_bus_insert_busn_res() (causing the memory leak),
nor printed:

   pci-rcar-gen2 ee090000.pci: host bridge /soc/pci@...90000 ranges:
   pci-rcar-gen2 ee090000.pci:      MEM 0x00ee080000..0x00ee08ffff -> 0x00ee080000
   pci-rcar-gen2 ee090000.pci: PCI: revision 11
   pci-rcar-gen2 ee090000.pci: PCI host bridge to bus 0000:00
  -pci_bus 0000:00: root bus resource [bus 00]
   pci_bus 0000:00: root bus resource [mem 0xee080000-0xee08ffff]

Fix this by only skipping resources where all of the flags, start, and end
members are zero.

The Linux kernel CVE team has assigned CVE-2023-53814 to this issue.


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

	Issue introduced in 5.16 with commit 7c3855c423b17f6ca211858afb0cef20569914c7 and fixed in 6.1.16 with commit fe6a1fbe83f5b23d7db93596b793561230f06b40
	Issue introduced in 5.16 with commit 7c3855c423b17f6ca211858afb0cef20569914c7 and fixed in 6.2.3 with commit 7e6f2714d93cdf977b6124a80af2cf0e14e2d407
	Issue introduced in 5.16 with commit 7c3855c423b17f6ca211858afb0cef20569914c7 and fixed in 6.3 with commit 9d8ba74a181b1c81def21168795ed96cbe6f05ed

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-2023-53814
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/probe.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/e4af080f3ef6a65b0d702988c2471a47c9ae2cc0
	https://git.kernel.org/stable/c/fe6a1fbe83f5b23d7db93596b793561230f06b40
	https://git.kernel.org/stable/c/7e6f2714d93cdf977b6124a80af2cf0e14e2d407
	https://git.kernel.org/stable/c/9d8ba74a181b1c81def21168795ed96cbe6f05ed