luks2: Make sure all fields of output argument in luks2_parse_digest() are written to

We should assume that the output argument "out" is uninitialized and could
have random data. So, make sure to initialize the segments and keyslots bit
fields because potentially not all bits of those fields are written to.
Otherwise, the digest could say it belongs to keyslots and segments that it
does not.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/grub-core/disk/luks2.c b/grub-core/disk/luks2.c
index 7b30734aa07c4170ffde1a7f7dfda39e37329758..371e868ab9d755e8606667ff44ed0a54d1f13636 100644 (file)
--- a/grub-core/disk/luks2.c
+++ b/grub-core/disk/luks2.c
@@ -230,6 +230,7 @@ luks2_parse_digest (grub_luks2_digest_t *out, const grub_json_t *digest)
     return grub_error (GRUB_ERR_BAD_ARGUMENT,
                       "Digest references no segments");
 
+  out->segments = 0;
   for (i = 0; i < size; i++)
     {
       if (grub_json_getchild (&o, &segments, i) ||
@@ -242,6 +243,7 @@ luks2_parse_digest (grub_luks2_digest_t *out, const grub_json_t *digest)
     return grub_error (GRUB_ERR_BAD_ARGUMENT,
                       "Digest references no keyslots");
 
+  out->keyslots = 0;
   for (i = 0; i < size; i++)
     {
       if (grub_json_getchild (&o, &keyslots, i) ||