CVE-2021-47005

In the Linux kernel, the following vulnerability has been resolved: PCI:
endpoint: Fix NULL pointer dereference for ->get_features() get_features
ops of pci_epc_ops may return NULL, causing NULL pointer dereference in
pci_epf_test_alloc_space function. Let us add a check for pci_epc_feature
pointer in pci_epf_test_bind before we access it to avoid any such NULL
pointer dereference and return -ENOTSUPP in case pci_epc_feature is not
found. When the patch is not applied and EPC features is not implemented in
the platform driver, we see the following dump due to kernel NULL pointer
dereference. Call trace: pci_epf_test_bind+0xf4/0x388
pci_epf_bind+0x3c/0x80 pci_epc_epf_link+0xa8/0xcc
configfs_symlink+0x1a4/0x48c vfs_symlink+0x104/0x184 do_symlinkat+0x80/0xd4
__arm64_sys_symlinkat+0x1c/0x24 el0_svc_common.constprop.3+0xb8/0x170
el0_svc_handler+0x70/0x88 el0_svc+0x8/0x640 Code: d2800581 b9403ab9
f9404ebb 8b394f60 (f9400400) —[ end trace a438e3c5a24f9df0 ]—

Bugs

• <https://bugzilla.redhat.com/show_bug.cgi?id=2266861&gt;
• <https://bugzilla.suse.com/show_bug.cgi?id=1220660&gt;

Notes