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.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:HI:HA:H7.8/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H