RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp

Browse source

rxe_qp_from_attr() handles IB_QP_MAX_DEST_RD_ATOMIC outside the
IB_QP_STATE path, so it holds no state_lock and runs while the responder
task rxe_receiver() (recv_task on rxe_wq) is live. A modify_qp() setting
only that attribute calls free_rd_atomic_resources() then
alloc_rd_atomic_resources(), swapping qp->resp.resources[] while
rxe_prepare_res()/find_resource() walk it; free_rd_atomic_resources()
also leaves the cached pointer qp->resp.res dangling. A local
unprivileged user can race the free/realloc into a use-after-free in
rxe_receiver() (local DoS).

Drain recv_task around the swap with rxe_disable_task()/rxe_enable_task(),
as rxe_qp_reset() already does when tearing this array down, re-enabling
only after alloc_rd_atomic_resources() succeeds so the responder never
resumes against a NULL qp->resp.resources on the ENOMEM path. Also clear
qp->resp.res in free_rd_atomic_resources(), like the rxe_resp.c
completion paths.

Reproduced under KASAN; the slab-use-after-free in rxe_receiver() is gone.

Fixes: 8700e3e7c4 ("Soft RoCE driver")
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Ibrahim Hashimov <security@auditcode.ai>
Link: https://patch.msgid.link/20260712121720.78001-1-security@auditcode.ai
Assisted-by: AuditCode-AI:2026.07
Signed-off-by: Leon Romanovsky <leon@kernel.org>

...

This commit is contained in:

Ibrahim Hashimov 2026-07-12 14:17:20 +02:00 • committed by Leon Romanovsky

parent 091c6162c0

commit 6f70142374

1 changed files with 14 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

15

drivers/infiniband/sw/rxe/rxe_qp.c

View file