Subject: CVE-2024-43824: PCI: endpoint: pci-epf-test: Make use of cached 'epc_features' in pci_epf_test_core_init()

From: Greg Kroah-Hartman <[email-masked]>

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

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

PCI: endpoint: pci-epf-test: Make use of cached 'epc_features' in pci_epf_test_core_init()

Instead of getting the epc_features from pci_epc_get_features() API, use
the cached pci_epf_test::epc_features value to avoid the NULL check. Since
the NULL check is already performed in pci_epf_test_bind(), having one more
check in pci_epf_test_core_init() is redundant and it is not possible to
hit the NULL pointer dereference.

Also with commit a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier"
flag"), 'epc_features' got dereferenced without the NULL check, leading to
the following false positive Smatch warning:

  drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init() error: we previously assumed 'epc_features' could be null (see line 747)

Thus, remove the redundant NULL check and also use the epc_features::
{msix_capable/msi_capable} flags directly to avoid local variables.

[kwilczynski: commit log]

The Linux kernel CVE team has assigned CVE-2024-43824 to this issue.

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

	Issue introduced in 5.7 with commit 5e50ee27d4a5 and fixed in 6.10.3 with commit af4ad016abb1
	Issue introduced in 5.7 with commit 5e50ee27d4a5 and fixed in 6.11 with commit 5a5095a8bd1b

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-2024-43824
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/endpoint/functions/pci-epf-test.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/af4ad016abb1632ff7ee598a6037952b495e5b80
	https://git.kernel.org/stable/c/5a5095a8bd1bd349cce1c879e5e44407a34dda8a