CVE-2021-47333

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge<br /> <br /> There is an issue with the ASPM(optional) capability checking function.<br /> A device might be attached to root complex directly, in this case,<br /> bus-&gt;self(bridge) will be NULL, thus priv-&gt;parent_pdev is NULL.<br /> Since alcor_pci_init_check_aspm(priv-&gt;parent_pdev) checks the PCI link&amp;#39;s<br /> ASPM capability and populate parent_cap_off, which will be used later by<br /> alcor_pci_aspm_ctrl() to dynamically turn on/off device, what we can do<br /> here is to avoid checking the capability if we are on the root complex.<br /> This will make pdev_cap_off 0 and alcor_pci_aspm_ctrl() will simply<br /> return when bring called, effectively disable ASPM for the device.<br /> <br /> [ 1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0<br /> [ 1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40<br /> [ 1.253998] Call Trace:<br /> [ 1.254131] ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci]<br /> [ 1.254476] alcor_pci_probe+0x169/0x2d5 [alcor_pci]