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Message-ID: <80d7474a-3a94-44a9-8e82-5831f1961ef5@grimberg.me>
Date: Wed, 8 May 2024 10:48:55 +0300
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Subject: Re: [PATCH] nvmet: prevent sprintf() overflow in
 nvmet_subsys_nsid_exists()
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Christoph Hellwig <hch@lst.de>, Chaitanya Kulkarni <kch@nvidia.com>,
 Keith Busch <kbusch@kernel.org>, linux-nvme@lists.infradead.org,
 linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
References: <25e9c58d-d192-4a91-ad40-4c2ea01fbdf5@moroto.mountain>
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From: Sagi Grimberg <sagi@grimberg.me>
In-Reply-To: <25e9c58d-d192-4a91-ad40-4c2ea01fbdf5@moroto.mountain>
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On 08/05/2024 10:43, Dan Carpenter wrote:
> The nsid value is a u32 that comes from nvmet_req_find_ns().  It's
> endian data and we're on an error path and both of those raise red
> flags.  So let's make this safer.
>
> 1) Make the buffer large enough for any u32.
> 2) Remove the unnecessary initialization.
> 3) Use snprintf() instead of sprintf() for even more safety.
> 4) The sprintf() function returns the number of bytes printed, not
>     counting the NUL terminator. It is impossible for the return value to
>     be <= 0 so delete that.
>
> Fixes: 505363957fad ("nvmet: fix nvme status code when namespace is disabled")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>