diff options
| author | Michael Bommarito <michael.bommarito@gmail.com> | 2026-05-17 17:30:10 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-05-18 08:59:12 -0600 |
| commit | cf18e36455603d65d4745de83e2d1743c54ada47 (patch) | |
| tree | 1b4c3c70d772e60402367d0a36c5d9270a457d3b | |
| parent | 93d93f5f8da791e98159795c6ef683f45bd95d13 (diff) | |
io_uring: propagate array_index_nospec opcode into req->opcode
Commit 1e988c3fe126 ("io_uring: prevent opcode speculation") added
array_index_nospec() to io_init_req(), but applied it only to a local
opcode variable. req->opcode is initialized from sqe->opcode before the
bounds check and remains the raw value.
Keep req->opcode as the canonical opcode in io_init_req(): reject
out-of-range values architecturally, then write the array_index_nospec()
result back to req->opcode before any table lookup. This keeps downstream
users of req->opcode from observing the raw user byte on a mispredicted
path.
No functional change: array_index_nospec() is a no-op for opcodes in
[0, IORING_OP_LAST), and out-of-range opcodes are still rejected at the
bounds check above the assignment.
Fixes: 1e988c3fe126 ("io_uring: prevent opcode speculation")
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://patch.msgid.link/20260517213010.696135-1-michael.bommarito@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/io_uring.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 036145ee466c..103b6c88f252 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1738,10 +1738,9 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_issue_def *def; unsigned int sqe_flags; int personality; - u8 opcode; req->ctx = ctx; - req->opcode = opcode = READ_ONCE(sqe->opcode); + req->opcode = READ_ONCE(sqe->opcode); /* same numerical values with corresponding REQ_F_*, safe to copy */ sqe_flags = READ_ONCE(sqe->flags); req->flags = (__force io_req_flags_t) sqe_flags; @@ -1751,13 +1750,13 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, req->cancel_seq_set = false; req->async_data = NULL; - if (unlikely(opcode >= IORING_OP_LAST)) { + if (unlikely(req->opcode >= IORING_OP_LAST)) { req->opcode = 0; return io_init_fail_req(req, -EINVAL); } - opcode = array_index_nospec(opcode, IORING_OP_LAST); + req->opcode = array_index_nospec(req->opcode, IORING_OP_LAST); - def = &io_issue_defs[opcode]; + def = &io_issue_defs[req->opcode]; if (def->is_128 && !(ctx->flags & IORING_SETUP_SQE128)) { /* * A 128b op on a non-128b SQ requires mixed SQE support as |