Bug 2338183 (CVE-2024-36476)

Summary: CVE-2024-36476 kernel: RDMA/rtrs: Ensure 'ib_sge list' is accessible
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-01-15 14:01:25 UTC 
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/
Comment 1 Robb Gatica 2025-01-15 15:45:50 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025011531-CVE-2024-36476-b2a1@gregkh/T