Use 'void *' for arbitrary buffers, 'uint8 *' for byte arrays

A 'void *' argument suggests that the caller might pass an arbitrary
struct, which is appropriate for functions like libc's read/write, or
pq_sendbytes(). 'uint8 *' is more appropriate for byte arrays that
have no structure, like the cancellation keys or SCRAM tokens. Some
places used 'char *', but 'uint8 *' is better because 'char *' is
commonly used for null-terminated strings. Change code around SCRAM,
MD5 authentication, and cancellation key handling to follow these
conventions.

Discussion: https://www.postgresql.org/message-id/61be9e31-7b7d-49d5-bc11-721800d89d64@eisentraut.org

3 files changed, 15 insertions, 15 deletions

diff --git a/src/common/base64.c b/src/common/base64.c
index 6028f413472..240461fe1e6 100644
--- a/src/common/base64.c
+++ b/src/common/base64.c
@@ -41,15 +41,15 @@ static const int8 b64lookup[128] = {
 /*
  * pg_b64_encode
  *
- * Encode into base64 the given string.  Returns the length of the encoded
- * string, and -1 in the event of an error with the result buffer zeroed
- * for safety.
+ * Encode the 'src' byte array into base64.  Returns the length of the encoded
+ * string, and -1 in the event of an error with the result buffer zeroed for
+ * safety.
  */
 int
-pg_b64_encode(const char *src, int len, char *dst, int dstlen)
+pg_b64_encode(const uint8 *src, int len, char *dst, int dstlen)
 {
 	char	   *p;
-	const char *s,
+	const uint8 *s,
 			   *end = src + len;
 	int			pos = 2;
 	uint32		buf = 0;
@@ -59,7 +59,7 @@ pg_b64_encode(const char *src, int len, char *dst, int dstlen)
 
 	while (s < end)
 	{
-		buf |= (unsigned char) *s << (pos << 3);
+		buf |= *s << (pos << 3);
 		pos--;
 		s++;
 
@@ -113,11 +113,11 @@ error:
  * buffer zeroed for safety.
  */
 int
-pg_b64_decode(const char *src, int len, char *dst, int dstlen)
+pg_b64_decode(const char *src, int len, uint8 *dst, int dstlen)
 {
 	const char *srcend = src + len,
 			   *s = src;
-	char	   *p = dst;
+	uint8	   *p = dst;
 	char		c;
 	int			b = 0;
 	uint32		buf = 0;
diff --git a/src/common/md5_common.c b/src/common/md5_common.c
index 61e396b0bbf..057ae7a449f 100644
--- a/src/common/md5_common.c
+++ b/src/common/md5_common.c
@@ -105,7 +105,7 @@ pg_md5_hash(const void *buff, size_t len, char *hexsum, const char **errstr)
  * (of size MD5_DIGEST_LENGTH) rather than being converted to ASCII hex.
  */
 bool
-pg_md5_binary(const void *buff, size_t len, void *outbuf, const char **errstr)
+pg_md5_binary(const void *buff, size_t len, uint8 *outbuf, const char **errstr)
 {
 	pg_cryptohash_ctx *ctx;
 
@@ -142,7 +142,7 @@ pg_md5_binary(const void *buff, size_t len, void *outbuf, const char **errstr)
  * error context.
  */
 bool
-pg_md5_encrypt(const char *passwd, const char *salt, size_t salt_len,
+pg_md5_encrypt(const char *passwd, const uint8 *salt, size_t salt_len,
 			   char *buf, const char **errstr)
 {
 	size_t		passwd_len = strlen(passwd);
diff --git a/src/common/scram-common.c b/src/common/scram-common.c
index bfd2a340016..e47a6ebbaab 100644
--- a/src/common/scram-common.c
+++ b/src/common/scram-common.c
@@ -37,7 +37,7 @@
 int
 scram_SaltedPassword(const char *password,
 					 pg_cryptohash_type hash_type, int key_length,
-					 const char *salt, int saltlen, int iterations,
+					 const uint8 *salt, int saltlen, int iterations,
 					 uint8 *result, const char **errstr)
 {
 	int			password_len = strlen(password);
@@ -62,7 +62,7 @@ scram_SaltedPassword(const char *password,
 
 	/* First iteration */
 	if (pg_hmac_init(hmac_ctx, (uint8 *) password, password_len) < 0 ||
-		pg_hmac_update(hmac_ctx, (uint8 *) salt, saltlen) < 0 ||
+		pg_hmac_update(hmac_ctx, salt, saltlen) < 0 ||
 		pg_hmac_update(hmac_ctx, (uint8 *) &one, sizeof(uint32)) < 0 ||
 		pg_hmac_final(hmac_ctx, Ui_prev, key_length) < 0)
 	{
@@ -207,7 +207,7 @@ scram_ServerKey(const uint8 *salted_password,
  */
 char *
 scram_build_secret(pg_cryptohash_type hash_type, int key_length,
-				   const char *salt, int saltlen, int iterations,
+				   const uint8 *salt, int saltlen, int iterations,
 				   const char *password, const char **errstr)
 {
 	uint8		salted_password[SCRAM_MAX_KEY_LEN];
@@ -290,7 +290,7 @@ scram_build_secret(pg_cryptohash_type hash_type, int key_length,
 	*(p++) = '$';
 
 	/* stored key */
-	encoded_result = pg_b64_encode((char *) stored_key, key_length, p,
+	encoded_result = pg_b64_encode(stored_key, key_length, p,
 								   encoded_stored_len);
 	if (encoded_result < 0)
 	{
@@ -307,7 +307,7 @@ scram_build_secret(pg_cryptohash_type hash_type, int key_length,
 	*(p++) = ':';
 
 	/* server key */
-	encoded_result = pg_b64_encode((char *) server_key, key_length, p,
+	encoded_result = pg_b64_encode(server_key, key_length, p,
 								   encoded_server_len);
 	if (encoded_result < 0)
 	{