[PATCH v2 1/1] lib: rsa: fix padding_pss_verify

[Heinrich Schuchardt]

Check the that the hash length is shorter than the message length. This
avoids:

    ./tools/../lib/rsa/rsa-verify.c:275:11: warning:
    ‘*db’ may be used uninitialized [-Wmaybe-uninitialized]
      275 |         db[0] &= 0xff >> leftmost_bits;

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
v2:
	Use -EINVAL to indicate incorrect parameters.
	Add description of return value.
---
 lib/rsa/rsa-verify.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 1d95cfbdee..f13cd23cf2 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -215,6 +215,8 @@ out:
  * @msg_len:	Message length
  * @hash:	Pointer to the expected hash
  * @hash_len:	Length of the hash
+ *
+ * Return:	0 if padding is correct, non-zero otherwise
  */
 int padding_pss_verify(struct image_sign_info *info,
 		       const uint8_t *msg, int msg_len,
@@ -234,6 +236,9 @@ int padding_pss_verify(struct image_sign_info *info,
 	uint8_t leftmost_mask;
 	struct checksum_algo *checksum = info->checksum;
 
+	if (db_len <= 0)
+		return -EINVAL;
+
 	/* first, allocate everything */
 	db_mask = malloc(db_len);
 	db = malloc(db_len);
-- 
2.37.2