[PATCH] keys, dns: Fix size check of V1 server-list header

[Simon Horman]

On Wed, Jan 10, 2024 at 09:11:40PM +0000, David Howells wrote:
>     
> Fix the size check added to dns_resolver_preparse() for the V1 server-list
> header so that it doesn't give EINVAL if the size supplied is the same as
> the size of the header struct (which should be valid).
> 
> This can be tested with:
> 
>         echo -n -e '\0\0\01\xff\0\0' | keyctl padd dns_resolver desc @p
> 
> which will give "add_key: Invalid argument" without this fix.
> 
> Fixes: 1997b3cb4217 ("keys, dns: Fix missing size check of V1 server-list header")
> Reported-by: Pengfei Xu <pengfei.xu at intel.com>
> Link: https://lore.kernel.org/r/ZZ4fyY4r3rqgZL+4@xpf.sh.intel.com/
> Signed-off-by: David Howells <dhowells at redhat.com>

Reviewed-by: Simon Horman <horms at kernel.org>