Re: [PATCH] luks2: Continue trying all keyslots even if there are some failures

[Patrick Steinhardt <ps@pks.im>]

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On Fri, Jul 22, 2022 at 03:04:50AM -0500, Glenn Washburn wrote:
> luks2_get_keyslot can fail for a variety of reasons that do not neccesarily
> mean the next keyslot should not be tried (eg. a new kdf type). So always
> try the next slot. This will make GRUB more resilient to non-spec json data
> that 3rd party systems may add. We do not care if some of the keyslots are
> unusable, only if there is at least one that is.
> 
> Signed-off-by: Glenn Washburn <development@efficientek.com>
> ---
>  grub-core/disk/luks2.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/grub-core/disk/luks2.c b/grub-core/disk/luks2.c
> index bf741d70f..d8d3180ed 100644
> --- a/grub-core/disk/luks2.c
> +++ b/grub-core/disk/luks2.c
> @@ -610,7 +610,15 @@ luks2_recover_key (grub_disk_t source,
>        grub_errno = GRUB_ERR_NONE;
>        ret = luks2_get_keyslot (&keyslot, &digest, &segment, json, json_idx);
>        if (ret)
> -	goto err;
> +	{
> +	  /*
> +	   * luks2_get_keyslot can fail for a variety of reasons that do not
> +	   * neccesarily mean the next keyslot should not be tried (eg. a new
> +	   * kdf type). So always try the next slot.
> +	   */
> +	  grub_dprintf ("luks2", "Failed to get keyslot %" PRIuGRUB_UINT64_T "\n", keyslot.idx);
> +	  continue;
> +	}
>        if (grub_errno != GRUB_ERR_NONE)
>  	  grub_dprintf ("luks2", "Ignoring unhandled error %d from luks2_get_keyslot\n", grub_errno);
>  
> -- 
> 2.34.1
> 

Reviewed-by: Patrick Steinhardt <ps@pks.im>

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