Re: [Qemu-devel] [PATCH 4/6] luks: Turn invalid assertion into check

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Mar 09, 2018 at 06:27:11PM +0100, Kevin Wolf wrote:
> The .bdrv_getlength implementation of the crypto block driver asserted
> that the payload offset isn't after EOF. This is an invalid assertion to
> make as the image file could be corrupted. Instead, check it and return
> -EIO if the file is too small for the payload offset.
> 
> Zero length images are fine, so trigger -EIO only on offset > len, not
> on offset >= len as the assertion did before.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/crypto.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/block/crypto.c b/block/crypto.c
> index 2035f9ab13..4908d8627f 100644
> --- a/block/crypto.c
> +++ b/block/crypto.c
> @@ -518,7 +518,10 @@ static int64_t block_crypto_getlength(BlockDriverState *bs)
>  
>      uint64_t offset = qcrypto_block_get_payload_offset(crypto->block);
>      assert(offset < INT64_MAX);
> -    assert(offset < len);
> +
> +    if (offset > len) {
> +       return -EIO;
> +    }
>  
>      len -= offset;

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Regards,
Daniel
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