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aio: avoid request count overflow in ioctx_alloc() - #2951
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ioctx_alloc() saves the 32-bit nr_events in max_reqs, then doubles nr_events before checking the ring-size bound. For nr_events=0x80000001, the doubled value wraps to 2, so the ring check passes and aio_setup_ring() builds a one-page/127-slot ring. The original 0x80000001 is still stored in ctx->max_reqs and charged to the global aio_nr quota. If an administrator has raised fs.aio-max-nr to at least 0x80000001, an unprivileged process can create that context and make later normal io_setup() calls fail with -EAGAIN until the wrapped context is destroyed. Check for too large number of requests before multiplying. Link: https://lore.kernel.org/all/20261022091748.3653127-1-teel4res@gmail.com Reported-by: Cheng Yongkang <teel4res@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
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Series: https://patchwork.kernel.org/project/linux-fsdevel/list/?series=1191250
Submitter: Jan Kara
Version: 1
Patches: 1/1
Message-ID:
<20261022112534.3513745-2-jack@suse.cz>Base: vfs.base.ci
Lore: https://lore.kernel.org/linux-fsdevel/20261022112534.3513745-2-jack@suse.cz
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