* [PATCH] io_uring: prevent speculating sq_array indexing
@ 2024-11-04 12:02 Pavel Begunkov
2024-11-04 16:19 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Pavel Begunkov @ 2024-11-04 12:02 UTC (permalink / raw)
To: io-uring; +Cc: Jens Axboe, asml.silence
The SQ index array consists of user provided indexes, which io_uring
then uses to index the SQ, and so it's susceptible to speculation. For
all other queues io_uring tracks heads and tails in kernel, and they
shouldn't need any special care.
Signed-off-by: Pavel Begunkov <[email protected]>
---
io_uring/io_uring.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index f34fa1ead2cf..406825d000eb 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2544,6 +2544,7 @@ static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
READ_ONCE(ctx->rings->sq_dropped) + 1);
return false;
}
+ head = array_index_nospec(head, ctx->sq_entries);
}
/*
--
2.46.0
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2024-11-04 12:02 [PATCH] io_uring: prevent speculating sq_array indexing Pavel Begunkov
2024-11-04 16:19 ` Jens Axboe
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