CVE-2023-53446

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> PCI/ASPM: Disable ASPM on MFD function removal to avoid use-after-free<br /> <br /> Struct pcie_link_state-&gt;downstream is a pointer to the pci_dev of function<br /> 0. Previously we retained that pointer when removing function 0, and<br /> subsequent ASPM policy changes dereferenced it, resulting in a<br /> use-after-free warning from KASAN, e.g.:<br /> <br /> # echo 1 &gt; /sys/bus/pci/devices/0000:03:00.0/remove<br /> # echo powersave &gt; /sys/module/pcie_aspm/parameters/policy<br /> <br /> BUG: KASAN: slab-use-after-free in pcie_config_aspm_link+0x42d/0x500<br /> Call Trace:<br /> kasan_report+0xae/0xe0<br /> pcie_config_aspm_link+0x42d/0x500<br /> pcie_aspm_set_policy+0x8e/0x1a0<br /> param_attr_store+0x162/0x2c0<br /> module_attr_store+0x3e/0x80<br /> <br /> PCIe spec r6.0, sec 7.5.3.7, recommends that software program the same ASPM<br /> Control value in all functions of multi-function devices.<br /> <br /> Disable ASPM and free the pcie_link_state when any child function is<br /> removed so we can discard the dangling pcie_link_state-&gt;downstream pointer<br /> and maintain the same ASPM Control configuration for all functions.<br /> <br /> [bhelgaas: commit log and comment]