diff options
| author | Melbin K Mathew <mlbnkm1@gmail.com> | 2026-07-01 10:11:45 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-07-01 05:39:26 -0600 |
| commit | 15cd3ccf9b179f0f76948d0901be3b15028bc768 (patch) | |
| tree | dc028efdb0937b2faa02213c94940294dc5ff6f0 | |
| parent | df645b745941ea829b39134ac342f730f4d9d978 (diff) | |
io_uring/msg_ring: reject CQE32 flag pass-through to normal rings
IORING_OP_MSG_RING with IORING_MSG_RING_FLAGS_PASS allows a sender to
pass completion flags through sqe->file_index. If the sender sets
IORING_CQE_F_32 in file_index, the target-side completion path treats it
as a 32b CQE and writes big_cqe[0] and big_cqe[1] into the CQ ring
regardless of whether the target ring was created with
IORING_SETUP_CQE32 or IORING_SETUP_CQE_MIXED.
On a normal 16b CQE ring, this writes 16 extra bytes (two u64 big_cqe
fields) into the next CQE slot in the ring buffer. As the receiving ring
doesn't understand 32b CQEs, this is incorrect and they should be
rejected.
Fixes: cbeb47a7b5f0 ("io_uring/msg_ring: Pass custom flags to the cqe")
Signed-off-by: Melbin K Mathew <mlbnkm1@gmail.com>
Link: https://patch.msgid.link/20260701081145.196730-1-mlbnkm1@gmail.com
[axboe: edit commit message]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/msg_ring.c | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c index 3ff9098573db..3067c9343991 100644 --- a/io_uring/msg_ring.c +++ b/io_uring/msg_ring.c @@ -93,19 +93,38 @@ static void io_msg_remote_post(struct io_ring_ctx *ctx, struct io_kiocb *req, io_req_task_work_add_remote(req, IOU_F_TWQ_LAZY_WAKE); } +static int io_msg_ring_cqe_flags(struct io_ring_ctx *target_ctx, + const struct io_msg *msg, u32 *flags) +{ + *flags = 0; + + if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS)) + return 0; + + *flags = msg->cqe_flags; + if ((*flags & IORING_CQE_F_32) && + !(target_ctx->flags & (IORING_SETUP_CQE32 | + IORING_SETUP_CQE_MIXED))) + return -EINVAL; + + return 0; +} + static int io_msg_data_remote(struct io_ring_ctx *target_ctx, struct io_msg *msg) { struct io_kiocb *target; - u32 flags = 0; + u32 flags; + int ret; - target = kmem_cache_alloc(req_cachep, GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO) ; + ret = io_msg_ring_cqe_flags(target_ctx, msg, &flags); + if (ret) + return ret; + + target = kmem_cache_alloc(req_cachep, GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO); if (unlikely(!target)) return -ENOMEM; - if (msg->flags & IORING_MSG_RING_FLAGS_PASS) - flags = msg->cqe_flags; - io_msg_remote_post(target_ctx, target, msg->len, flags, msg->user_data); return 0; } @@ -130,8 +149,9 @@ static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, if (io_msg_need_remote(target_ctx)) return io_msg_data_remote(target_ctx, msg); - if (msg->flags & IORING_MSG_RING_FLAGS_PASS) - flags = msg->cqe_flags; + ret = io_msg_ring_cqe_flags(target_ctx, msg, &flags); + if (ret) + return ret; ret = -EOVERFLOW; if (target_ctx->flags & IORING_SETUP_IOPOLL) { |