جزئیات آسیب‌پذیری

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: make release_scratchbuffers idempotent brcmf_pcie_release_scratchbuffers() frees the shared.scratch and shared.ringupd DMA buffers with dma_free_coherent() but does not clear the pointers afterwards, unlike the sibling release_ringbuffers() which NULLs commonrings/flowrings/idxbuf on release. Both the bus_reset .reset callback (brcmf_pcie_reset) and brcmf_pcie_remove() call release_scratchbuffers. When reset teardown has run before removal, remove's own teardown would call dma_free_coherent() a second time on the already-freed DMA allocation. NULL the pointers after free, matching release_ringbuffers(), so a later release observes that the allocation has already been released. This patch makes repeated sequential release safe; the reset-work lifetime is handled separately by the following patch. This issue was found by an in-house static analysis tool.

• https://git.kernel.org/stable/c/81c58a206d1deee01f4c29236d4154c0872f2a38
• https://git.kernel.org/stable/c/382ee00b2d1e31869ae576a60d3fbe7a2153512f
• https://git.kernel.org/stable/c/739b686aecdb14a6065300ea53401f043e51fd22
• https://git.kernel.org/stable/c/b7d1d8cb1bdca56aecebacd2896615da0acc126a
• https://git.kernel.org/stable/c/5a045c2f0fbf029873d2295178fa0785ade35af0
• https://git.kernel.org/stable/c/044fca8f45ba9ab6ca526163155234cf88287ff5
• https://git.kernel.org/stable/c/0ca80328df23f851c86866720d4977783c919ee6
• https://git.kernel.org/stable/c/538c51e9d124cf656f2dd0c0394a8545efc7102d