lib: rsa: fix padding_pss_verify

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;

Fixes: 061daa0b61f0 ("rsa: add support of padding pss")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 1d95cfbdee0c867abd1723e2fed3917442f2a180..9605c376390a9ef8ba00e39aac487208200a7eb1 100644 (file)
--- 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);