From: Jonathan McDowell <noodles@earth.li>
Date: Tue, 20 Aug 2019 07:12:52 +0000 (+0100)
Subject: Clean up signature hash calculation code
X-Git-Tag: onak-0.6.0~25
X-Git-Url: https://the.earth.li/gitweb/?p=onak.git;a=commitdiff_plain;h=7a255dd9b5307228b6706904d3def738c3628e45

Clean up signature hash calculation code

Use the defined digest lengths for MD5/SHA1/SHA1X rather than magic
numbers, clear the hash type at the start and then only set it if we
know it.
---

diff --git a/sigcheck.c b/sigcheck.c
index 0f93a31..89b3f92 100644
--- a/sigcheck.c
+++ b/sigcheck.c
@@ -63,6 +63,9 @@ onak_status_t calculate_packet_sighash(struct openpgp_publickey *key,
 	uint64_t keyid;
 	onak_status_t res;
 
+	*hashtype = 0;
+	*sighash = NULL;
+
 	switch (sig->data[0]) {
 	case 2:
 	case 3:
@@ -108,8 +111,6 @@ onak_status_t calculate_packet_sighash(struct openpgp_publickey *key,
 		hashlen[1] = key->publickey->length;
 		chunks = 2;
 
-		*hashtype = sig->data[3];
-
 		/* Check to see if this is an X509 based signature */
 		if (sig->data[2] == 0 || sig->data[2] == 100) {
 			size_t len;
@@ -136,6 +137,8 @@ onak_status_t calculate_packet_sighash(struct openpgp_publickey *key,
 			}
 		}
 
+		*hashtype = sig->data[3];
+
 		if (packet != NULL) {
 			if (packet->tag == OPENPGP_PACKET_PUBLICSUBKEY) {
 				packetheader[0] = 0x99;
@@ -262,21 +265,21 @@ onak_status_t calculate_packet_sighash(struct openpgp_publickey *key,
 		for (i = 0; i < chunks; i++) {
 			md5_update(&md5_context, hashlen[i], hashdata[i]);
 		}
-		md5_digest(&md5_context, 16, hash);
+		md5_digest(&md5_context, MD5_DIGEST_SIZE, hash);
 		break;
 	case OPENPGP_HASH_SHA1:
 		sha1_init(&sha1_context);
 		for (i = 0; i < chunks; i++) {
 			sha1_update(&sha1_context, hashlen[i], hashdata[i]);
 		}
-		sha1_digest(&sha1_context, 20, hash);
+		sha1_digest(&sha1_context, SHA1_DIGEST_SIZE, hash);
 		break;
 	case OPENPGP_HASH_SHA1X:
 		sha1x_init(&sha1x_context);
 		for (i = 0; i < chunks; i++) {
 			sha1x_update(&sha1x_context, hashlen[i], hashdata[i]);
 		}
-		sha1x_digest(&sha1x_context, 20, hash);
+		sha1x_digest(&sha1x_context, SHA1X_DIGEST_SIZE, hash);
 		break;
 #ifdef HAVE_NETTLE
 	case OPENPGP_HASH_RIPEMD160: