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

Overview

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]

Affected

• Linux >= 5e50ee27d4a52a817ab152128c48690ec7c5cdf1 < 97cee643a825808711cc78475fd61a30824b7a0f
• Linux >= 5e50ee27d4a52a817ab152128c48690ec7c5cdf1 < af4ad016abb1632ff7ee598a6037952b495e5b80
• Linux >= 5e50ee27d4a52a817ab152128c48690ec7c5cdf1 < 5a5095a8bd1bd349cce1c879e5e44407a34dda8a
• Linux 5.7

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.