Re: [PATCH] uimage: fix CRC32 verification on NFS

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Oct 02, 2024 at 06:07:15PM +0200, Ahmad Fatoum wrote:
> Reading a file over NFS is prone to return short reads as the file
> content is split over multiple UDP packets and reads won't return
> more than the number of bytes that have gathered in the FIFO.
> 
> The uImage verification code didn't account for this and handled neither
> short reads or the file prematurely ending.

Short reads shouldn't be a problem in the code you are touching here.
Have you moved this part to "uimage: use read_full where appropriate"
and didn't adjust the commit message?

> 
> Address both to fix this unexpected result:
> 
>   uimage -v /mnt/nfs/uImage
>   verifying data CRC... Bad Data CRC: 0x56474aa2 != 0x6b8f0a9c
> 
>   cp /mnt/nfs/uImage .
>   uimage -v uImage
>   verifying data CRC... ok
> 
> Fixes: 390249968c4e ("reimplement uImage code")
> Closes: https://github.com/barebox/barebox/issues/28
> Reported-by: Rashidwi <rashidwinter@gmail.com>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  common/uimage.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/common/uimage.c b/common/uimage.c
> index 140a08c1e426..c578edae2606 100644
> --- a/common/uimage.c
> +++ b/common/uimage.c
> @@ -272,7 +272,9 @@ int uimage_verify(struct uimage_handle *handle)
>  		ret = read(handle->fd, buf, now);
>  		if (ret < 0)
>  			goto err;
> -		crc = crc32(crc, buf, now);
> +		if (!ret)
> +			break;

Should we have an extra error message in this case? The information that
a uImage is shorter than expected might be valuable for the user.

Sascha

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