Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix double free in rxe_srq_from_init In rxe_srq_from_init(), the queue pointer 'q' is assigned to 'srq->rq.queue' before copying the SRQ number to user space. If copy_to_user() fails, the function calls rxe_queue_cleanup() to free the queue, but leaves the now-invalid pointer in 'srq->rq.queue'. The caller of rxe_srq_from_init() (rxe_create_srq) eventually calls rxe_srq_cleanup() upon receiving the error, which triggers a second rxe_queue_cleanup() on the same memory, leading to a double free. The call trace looks like this: kmem_cache_free+0x.../0x... rxe_queue_cleanup+0x1a/0x30 [rdma_rxe] rxe_srq_cleanup+0x42/0x60 [rdma_rxe] rxe_elem_release+0x31/0x70 [rdma_rxe] rxe_create_srq+0x12b/0x1a0 [rdma_rxe] ib_create_srq_user+0x9a/0x150 [ib_core] Fix this by moving 'srq->rq.queue = q' after copy_to_user.

References 8

• git.kernel.org https://git.kernel.org/stable/c/0beefd0e15d962f497aad750b2d5e9c3570b66d1
• git.kernel.org https://git.kernel.org/stable/c/26793db60925df1e88a29466813d586cbc190b8c
• git.kernel.org https://git.kernel.org/stable/c/26a9cfe12f4ffdeaa136f252478986fa5f397ddc
• git.kernel.org https://git.kernel.org/stable/c/5c07aef09a121a4cd622a71eb0753a9e135c84a8
• git.kernel.org https://git.kernel.org/stable/c/9abff51163aa1bc275ec356f74fe976291860a7f
• git.kernel.org https://git.kernel.org/stable/c/b98ab5494dbd48652561aa0b9c32f10500220745
• git.kernel.org https://git.kernel.org/stable/c/ce6f8e007682f378279d4cf83b240f12d52c723b
• git.kernel.org https://git.kernel.org/stable/c/d493e0bfc748a520c349d6c8791b262aa5ad2e4e

Remediation