CVE-2024-36476

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rtrs: Ensure ib_sge list is accessible

Move the declaration of the ib_sge list variable outside the always_invalidate block to ensure it remains accessible for use throughout the function.

Previously, ib_sge list was declared within the always_invalidate block, limiting its accessibility, then caused a BUG: kernel NULL pointer dereference[1]. ? __die_body.cold+0x19/0x27 ? page_fault_oops+0x15a/0x2d0 ? search_module_extables+0x19/0x60 ? search_bpf_extables+0x5f/0x80 ? exc_page_fault+0x7e/0x180 ? asm_exc_page_fault+0x26/0x30 ? memcpy_orig+0xd5/0x140 rxe_mr_copy+0x1c3/0x200 [rdma_rxe] ? rxe_pool_get_index+0x4b/0x80 [rdma_rxe] copy_data+0xa5/0x230 [rdma_rxe] rxe_requester+0xd9b/0xf70 [rdma_rxe] ? finish_task_switch.isra.0+0x99/0x2e0 rxe_sender+0x13/0x40 [rdma_rxe] do_task+0x68/0x1e0 [rdma_rxe] process_one_work+0x177/0x330 worker_thread+0x252/0x390 ? __pfx_worker_thread+0x10/0x10

This change ensures the variable is available for subsequent operations that require it.

[1] https://lore.kernel.org/linux-rdma/6a1f3e8f-deb0-49f9-bc69-a9b03ecfcda7@fujitsu.com/

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/143378075904e78b3b2a810099bcc3b3d82d762f
• https://git.kernel.org/stable/c/32e1e748a85bd52b20b3857d80fd166d22fa455a
• https://git.kernel.org/stable/c/6ffb5c1885195ae5211a12b4acd2d51843ca41b0
• https://git.kernel.org/stable/c/7eaa71f56a6f7ab87957213472dc6d4055862722
• https://git.kernel.org/stable/c/b238f61cc394d5fef27b26d7d9aa383ebfddabb0
• https://git.kernel.org/stable/c/fb514b31395946022f13a08e06a435f53cf9e8b3