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

[Glenn Washburn <development@efficientek.com>]

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