Static analysis cleanup: dead code, format string, size_t nits

A grab-bag of small cppcheck findings, none independently significant
but worth cleaning up together:

- libvbr/vbr.c, librbl/rbl.c: remove a dead "if (ret == -1) {...} else
  {...}" block in the DNS query path. An identical "ret == -1" check
  earlier in the same function already returns on that condition, so
  the else branch always ran; cppcheck confirms both conditions are
  always false.

- libopendkim/dkim-test.c: fix %zd/%zu format string mismatch
  (outkey_len and sig_keylen are size_t, not ssize_t) and a "key do
  not match" -> "keys do not match" typo to match nearby wording.

- libopendkim/dkim.c, dkim_sign(): dkim_base64_decode() returns int
  (-1 on error) but was assigned directly into dkim_keylen, which is
  size_t; "dkim_keylen <= 0" never caught the -1 case since it wraps
  to SIZE_MAX. Not reachable via opendkim-genkey (always produces PEM),
  but a real hazard for any direct libopendkim caller passing a bare
  base64-DER key. Now captured in an int local and checked before
  assigning into the size_t field.

- libopendkim/dkim.c, dkim_process_set(): initialize "end" in the "t"
  and "x" tag validation so it's not left uninitialized on paths where
  it's currently only safe because of short-circuit evaluation.

- libopendkim/dkim.c, dkim_getsighdr_d(): simplify a dead "if (!first)"
  check in the tag-wrapping loop -- by the time that branch is
  reached, "first" is already guaranteed FALSE (the branch above
  already handles "len == 0 || first"), so the check and the trailing
  reassignment were both no-ops. cppcheck: "Condition '!first' is
  always true".

- libopendkim/base32.c, dkim_base32_encode(): remove a redundant
  "iin >= size" clause from three of the unrolled loop's bounds
  checks, each of which immediately re-tests a value already proven
  false by an identical check a few lines above with no intervening
  change to "iin". cppcheck: "Condition 'iin>=size' is always false"
  (x3).

Author: thegushi

libopendkim/base32.c

@@ -69,7 +69,7 @@ dkim_base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 		buf[iout] = cb32[((udata[iin] & 0xf8) >> 3)];
 		iout++;
 
-		if (iout >= *buflen || iin >= size)
+		if (iout >= *buflen)
 		{
 			iout--; 	/* previous char is useless */
 			break;
@@ -86,7 +86,7 @@ dkim_base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 		buf[iout] = cb32[((udata[iin] & 0x3e) >> 1)];
 		iout++;
 
-		if (iout >= *buflen || iin >= size)
+		if (iout >= *buflen)
 		{
 			iout--;		/* previous char is useless */
 			break;
@@ -110,7 +110,7 @@ dkim_base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 		buf[iout] = cb32[((udata[iin] & 0x7c) >> 2)];
 		iout++;
 
-		if (iout >= *buflen || iin >= size)
+		if (iout >= *buflen)
 		{
 			iout--;		/* previous char is useless */
 			break;

libopendkim/dkim-test.c

@@ -507,7 +507,7 @@ dkim_test_key2(DKIM_LIB *lib, char *selector, char *domain,
 		{
 			status = 1;
 			snprintf(err, errlen,
-				 "key do not match: local = %zd, remote = %zd",
+				 "keys do not match: local = %zu, remote = %zu",
 			         outkey_len, sig->sig_keylen);
 		}
 

libopendkim/dkim.c

@@ -872,7 +872,7 @@ dkim_process_set(DKIM *dkim, dkim_set_t type, u_char *str, size_t len,
 		if (value != NULL)
 		{
 			uint64_t tmp = 0;
-			char *end;
+			char *end = NULL;
 
 			errno = 0;
 
@@ -909,7 +909,7 @@ dkim_process_set(DKIM *dkim, dkim_set_t type, u_char *str, size_t len,
 		if (value != NULL)
 		{
 			uint64_t tmp = 0;
-			char *end;
+			char *end = NULL;
 
 			errno = 0;
 
@@ -5425,6 +5425,7 @@ dkim_sign(DKIM_LIB *libhandle, const unsigned char *id, void *memclosure,
 		if (strncmp((char *) secretkey, "MII", 3) == 0)
 		{
 			size_t b64len;
+			int declen;
 
 			b64len = strlen((char *) secretkey);
 
@@ -5437,15 +5438,16 @@ dkim_sign(DKIM_LIB *libhandle, const unsigned char *id, void *memclosure,
 				return NULL;
 			}
 
-			new->dkim_keylen = dkim_base64_decode(secretkey,
-			                                      new->dkim_key,
-			                                      b64len);
-			if (new->dkim_keylen <= 0)
+			declen = dkim_base64_decode(secretkey, new->dkim_key,
+			                            b64len);
+			if (declen <= 0)
 			{
 				*statp = DKIM_STAT_NORESOURCE;
 				dkim_free(new);
 				return NULL;
 			}
+
+			new->dkim_keylen = (size_t) declen;
 		}
 		else
 		{
@@ -7541,14 +7543,12 @@ dkim_getsighdr_d(DKIM *dkim, size_t initial, u_char **buf, size_t *buflen)
 			}
 			else
 			{
-				if (!first)
-				{
-					dkim_dstring_cat1(dkim->dkim_hdrbuf,
-					                  ' ');
-					len += 1;
-				}
+				/* "first" is always FALSE here: this branch is
+				   only reached when the "len == 0 || first"
+				   branch above was not taken */
+				dkim_dstring_cat1(dkim->dkim_hdrbuf, ' ');
+				len += 1;
 
-				first = FALSE;
 				dkim_dstring_catn(dkim->dkim_hdrbuf,
 				                  (u_char *) pv,
 				                  pvlen);

librbl/rbl.c

@@ -183,16 +183,8 @@ rbl_res_query(void *srv, int type, unsigned char *query, unsigned char *buf,
 	if (rq == NULL)
 		return RBL_DNS_ERROR;
 
-	if (ret == -1)
-	{
-		rq->rq_error = errno;
-		rq->rq_buflen = 0;
-	}
-	else
-	{
-		rq->rq_error = 0;
-		rq->rq_buflen = (size_t) ret;
-	}
+	rq->rq_error = 0;
+	rq->rq_buflen = (size_t) ret;
 
 	*qh = (void *) rq;
 

libvbr/vbr.c

@@ -487,16 +487,8 @@ vbr_res_query(void *srv, int type, unsigned char *query, unsigned char *buf,
 	if (vq == NULL)
 		return VBR_DNS_ERROR;
 
-	if (ret == -1)
-	{
-		vq->vq_error = errno;
-		vq->vq_buflen = 0;
-	}
-	else
-	{
-		vq->vq_error = 0;
-		vq->vq_buflen = (size_t) ret;
-	}
+	vq->vq_error = 0;
+	vq->vq_buflen = (size_t) ret;
 
 	*qh = (void *) vq;