lib/digsig: pkcs_1_v1_5_decode_emsa cleanup

Removed useless 'is_valid' variable in pkcs_1_v1_5_decode_emsa(),
which was inhereted from original code. Client now uses return value
to check for an error.

Signed-off-by: Dmitry Kasatkin <[email protected]>
Reviewed-by: Tetsuo Handa <[email protected]>
Signed-off-by: James Morris <[email protected]>

lib/digsig.c

@@ -34,14 +34,9 @@ static int pkcs_1_v1_5_decode_emsa(const unsigned char *msg,
 			unsigned long  msglen,
 			unsigned long  modulus_bitlen,
 			unsigned char *out,
-			unsigned long *outlen,
-			int *is_valid)
+			unsigned long *outlen)
 {
 	unsigned long modulus_len, ps_len, i;
-	int result;
-
-	/* default to invalid packet */
-	*is_valid = 0;
 
 	modulus_len = (modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0);
 
@@ -50,39 +45,30 @@ static int pkcs_1_v1_5_decode_emsa(const unsigned char *msg,
 		return -EINVAL;
 
 	/* separate encoded message */
-	if ((msg[0] != 0x00) || (msg[1] != (unsigned char)1)) {
-		result = -EINVAL;
-		goto bail;
-	}
+	if ((msg[0] != 0x00) || (msg[1] != (unsigned char)1))
+		return -EINVAL;
 
 	for (i = 2; i < modulus_len - 1; i++)
 		if (msg[i] != 0xFF)
 			break;
 
 	/* separator check */
-	if (msg[i] != 0) {
+	if (msg[i] != 0)
 		/* There was no octet with hexadecimal value 0x00
 		to separate ps from m. */
-		result = -EINVAL;
-		goto bail;
-	}
+		return -EINVAL;
 
 	ps_len = i - 2;
 
 	if (*outlen < (msglen - (2 + ps_len + 1))) {
 		*outlen = msglen - (2 + ps_len + 1);
-		result = -EOVERFLOW;
-		goto bail;
+		return -EOVERFLOW;
 	}
 
 	*outlen = (msglen - (2 + ps_len + 1));
 	memcpy(out, &msg[2 + ps_len + 1], *outlen);
 
-	/* valid packet */
-	*is_valid = 1;
-	result    = 0;
-bail:
-	return result;
+	return 0;
 }
 
 /*
@@ -96,7 +82,7 @@ static int digsig_verify_rsa(struct key *key,
 	unsigned long len;
 	unsigned long mlen, mblen;
 	unsigned nret, l;
-	int valid, head, i;
+	int head, i;
 	unsigned char *out1 = NULL, *out2 = NULL;
 	MPI in = NULL, res = NULL, pkey[2];
 	uint8_t *p, *datap, *endp;
@@ -172,10 +158,9 @@ static int digsig_verify_rsa(struct key *key,
 	memset(out1, 0, head);
 	memcpy(out1 + head, p, l);
 
-	err = -EINVAL;
-	pkcs_1_v1_5_decode_emsa(out1, len, mblen, out2, &len, &valid);
+	err = pkcs_1_v1_5_decode_emsa(out1, len, mblen, out2, &len);
 
-	if (valid && len == hlen)
+	if (!err && len == hlen)
 		err = memcmp(out2, h, hlen);
 
 err: