trusted-keys: check hex2bin result

For each hex2bin call in trusted keys, check that the ascii hex string is
valid.  On failure, return -EINVAL.

Changelog v1:
- hex2bin now returns an int
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>

security/keys/trusted.c

@@ -779,7 +779,10 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
 			opt->pcrinfo_len = strlen(args[0].from) / 2;
 			if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
 				return -EINVAL;
-			hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
+			res = hex2bin(opt->pcrinfo, args[0].from,
+				      opt->pcrinfo_len);
+			if (res < 0)
+				return -EINVAL;
 			break;
 		case Opt_keyhandle:
 			res = strict_strtoul(args[0].from, 16, &handle);
@@ -791,12 +794,18 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
 		case Opt_keyauth:
 			if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 				return -EINVAL;
-			hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
+			res = hex2bin(opt->keyauth, args[0].from,
+				      SHA1_DIGEST_SIZE);
+			if (res < 0)
+				return -EINVAL;
 			break;
 		case Opt_blobauth:
 			if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 				return -EINVAL;
-			hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
+			res = hex2bin(opt->blobauth, args[0].from,
+				      SHA1_DIGEST_SIZE);
+			if (res < 0)
+				return -EINVAL;
 			break;
 		case Opt_migratable:
 			if (*args[0].from == '0')
@@ -860,7 +869,9 @@ static int datablob_parse(char *datablob, struct trusted_key_payload *p,
 		p->blob_len = strlen(c) / 2;
 		if (p->blob_len > MAX_BLOB_SIZE)
 			return -EINVAL;
-		hex2bin(p->blob, c, p->blob_len);
+		ret = hex2bin(p->blob, c, p->blob_len);
+		if (ret < 0)
+			return -EINVAL;
 		ret = getoptions(datablob, p, o);
 		if (ret < 0)
 			return ret;