In the Linux kernel, the following vulnerability has been resolved:
PCI: endpoint: pci-epf-test: Fix double free that causes kernel to oops
Fix a kernel oops found while testing the stm32_pcie Endpoint driver
with handling of PERST# deassertion:
During EP initialization, pci_epf_test_alloc_space() allocates all BARs,
which are further freed if epc_set_bar() fails (for instance, due to no
free inbound window).
However, when pci_epc_set_bar() fails, the error path:
pci_epc_set_bar() ->
pci_epf_free_space()
does not clear the previous assignment to epf_test->reg[bar].
Then, if the host reboots, the PERST# deassertion restarts the BAR
allocation sequence with the same allocation failure (no free inbound
window), creating a double free situation since epf_test->reg[bar] was
deallocated and is still non-NULL.
Thus, make sure that pci_epf_alloc_space() and pci_epf_free_space()
invocations are symmetric, and as such, set epf_test->reg[bar] to NULL
when memory is freed.
[kwilczynski: commit log]