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

6 files changed, 24 insertions, 24 deletions

diff --git a/src/interfaces/libpq/fe-auth-scram.c b/src/interfaces/libpq/fe-auth-scram.c
index fe18615197f..f6d6a5aa977 100644
--- a/src/interfaces/libpq/fe-auth-scram.c
+++ b/src/interfaces/libpq/fe-auth-scram.c
@@ -70,14 +70,14 @@ typedef struct
 
 	/* These come from the server-first message */
 	char	   *server_first_message;
-	char	   *salt;
+	uint8	   *salt;
 	int			saltlen;
 	int			iterations;
 	char	   *nonce;
 
 	/* These come from the server-final message */
 	char	   *server_final_message;
-	char		ServerSignature[SCRAM_MAX_KEY_LEN];
+	uint8		ServerSignature[SCRAM_MAX_KEY_LEN];
 } fe_scram_state;
 
 static bool read_server_first_message(fe_scram_state *state, char *input);
@@ -350,7 +350,7 @@ static char *
 build_client_first_message(fe_scram_state *state)
 {
 	PGconn	   *conn = state->conn;
-	char		raw_nonce[SCRAM_RAW_NONCE_LEN + 1];
+	uint8		raw_nonce[SCRAM_RAW_NONCE_LEN + 1];
 	char	   *result;
 	int			channel_info_len;
 	int			encoded_len;
@@ -513,7 +513,7 @@ build_client_final_message(fe_scram_state *state)
 			free(cbind_input);
 			goto oom_error;
 		}
-		encoded_cbind_len = pg_b64_encode(cbind_input, cbind_input_len,
+		encoded_cbind_len = pg_b64_encode((uint8 *) cbind_input, cbind_input_len,
 										  buf.data + buf.len,
 										  encoded_cbind_len);
 		if (encoded_cbind_len < 0)
@@ -574,7 +574,7 @@ build_client_final_message(fe_scram_state *state)
 	encoded_len = pg_b64_enc_len(state->key_length);
 	if (!enlargePQExpBuffer(&buf, encoded_len))
 		goto oom_error;
-	encoded_len = pg_b64_encode((char *) client_proof,
+	encoded_len = pg_b64_encode(client_proof,
 								state->key_length,
 								buf.data + buf.len,
 								encoded_len);
@@ -694,7 +694,7 @@ read_server_final_message(fe_scram_state *state, char *input)
 {
 	PGconn	   *conn = state->conn;
 	char	   *encoded_server_signature;
-	char	   *decoded_server_signature;
+	uint8	   *decoded_server_signature;
 	int			server_signature_len;
 
 	state->server_final_message = strdup(input);
@@ -916,7 +916,7 @@ pg_fe_scram_build_secret(const char *password, int iterations, const char **errs
 {
 	char	   *prep_password;
 	pg_saslprep_rc rc;
-	char		saltbuf[SCRAM_DEFAULT_SALT_LEN];
+	uint8		saltbuf[SCRAM_DEFAULT_SALT_LEN];
 	char	   *result;
 
 	/*
diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index ec7a9236044..84a042269de 100644
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -798,7 +798,7 @@ pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 	int			ret;
 	char	   *crypt_pwd = NULL;
 	const char *pwd_to_send;
-	char		md5Salt[4];
+	uint8		md5Salt[4];
 
 	/* Read the salt from the AuthenticationMD5Password message. */
 	if (areq == AUTH_REQ_MD5)
@@ -829,7 +829,7 @@ pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
 				}
 
 				crypt_pwd2 = crypt_pwd + MD5_PASSWD_LEN + 1;
-				if (!pg_md5_encrypt(password, conn->pguser,
+				if (!pg_md5_encrypt(password, (uint8 *) conn->pguser,
 									strlen(conn->pguser), crypt_pwd2,
 									&errstr))
 				{
@@ -1369,7 +1369,7 @@ PQencryptPassword(const char *passwd, const char *user)
 	if (!crypt_pwd)
 		return NULL;
 
-	if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
+	if (!pg_md5_encrypt(passwd, (uint8 *) user, strlen(user), crypt_pwd, &errstr))
 	{
 		free(crypt_pwd);
 		return NULL;
@@ -1482,7 +1482,7 @@ PQencryptPasswordConn(PGconn *conn, const char *passwd, const char *user,
 		{
 			const char *errstr = NULL;
 
-			if (!pg_md5_encrypt(passwd, user, strlen(user), crypt_pwd, &errstr))
+			if (!pg_md5_encrypt(passwd, (uint8 *) user, strlen(user), crypt_pwd, &errstr))
 			{
 				libpq_append_conn_error(conn, "could not encrypt password: %s", errstr);
 				free(crypt_pwd);
diff --git a/src/interfaces/libpq/fe-cancel.c b/src/interfaces/libpq/fe-cancel.c
index 25de2a337c9..8c7c198a530 100644
--- a/src/interfaces/libpq/fe-cancel.c
+++ b/src/interfaces/libpq/fe-cancel.c
@@ -463,7 +463,7 @@ PQsendCancelRequest(PGconn *cancelConn)
 	memset(&req, 0, offsetof(CancelRequestPacket, cancelAuthCode));
 	req.cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
 	req.backendPID = pg_hton32(cancelConn->be_pid);
-	if (pqPutnchar((char *) &req, offsetof(CancelRequestPacket, cancelAuthCode), cancelConn))
+	if (pqPutnchar(&req, offsetof(CancelRequestPacket, cancelAuthCode), cancelConn))
 		return STATUS_ERROR;
 	if (pqPutnchar(cancelConn->be_cancel_key, cancelConn->be_cancel_key_len, cancelConn))
 		return STATUS_ERROR;
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 2648df93813..c14e3c95250 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -67,7 +67,7 @@ PQlibVersion(void)
 
 
 /*
- * pqGetc: get 1 character from the connection
+ * pqGetc: read 1 character from the connection
  *
  *	All these routines return 0 on success, EOF on error.
  *	Note that for the Get routines, EOF only means there is not enough
@@ -100,7 +100,7 @@ pqPutc(char c, PGconn *conn)
 
 /*
  * pqGets[_append]:
- * get a null-terminated string from the connection,
+ * read a null-terminated string from the connection,
  * and store it in an expansible PQExpBuffer.
  * If we run out of memory, all of the string is still read,
  * but the excess characters are silently discarded.
@@ -159,10 +159,10 @@ pqPuts(const char *s, PGconn *conn)
 
 /*
  * pqGetnchar:
- *	get a string of exactly len bytes in buffer s, no null termination
+ *	read exactly len bytes in buffer s, no null termination
  */
 int
-pqGetnchar(char *s, size_t len, PGconn *conn)
+pqGetnchar(void *s, size_t len, PGconn *conn)
 {
 	if (len > (size_t) (conn->inEnd - conn->inCursor))
 		return EOF;
@@ -199,7 +199,7 @@ pqSkipnchar(size_t len, PGconn *conn)
  *	write exactly len bytes to the current message
  */
 int
-pqPutnchar(const char *s, size_t len, PGconn *conn)
+pqPutnchar(const void *s, size_t len, PGconn *conn)
 {
 	if (pqPutMsgBytes(s, len, conn))
 		return EOF;
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 3a1ac398fd0..beb1c889aad 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -2121,7 +2121,7 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
 		}
 		else
 		{
-			if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
+			if (pqPutnchar(args[i].u.ptr, args[i].len, conn))
 				return NULL;
 		}
 	}
@@ -2215,7 +2215,7 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
 					}
 					else
 					{
-						if (pqGetnchar((char *) result_buf,
+						if (pqGetnchar(result_buf,
 									   *actual_result_len,
 									   conn))
 							continue;
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 3d8a5045b98..a6cfd7f5c9d 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -539,16 +539,16 @@ struct pg_conn
 								 * tried host */
 	bool		send_appname;	/* okay to send application_name? */
 	size_t		scram_client_key_len;
-	void	   *scram_client_key_binary;	/* binary SCRAM client key */
+	uint8	   *scram_client_key_binary;	/* binary SCRAM client key */
 	size_t		scram_server_key_len;
-	void	   *scram_server_key_binary;	/* binary SCRAM server key */
+	uint8	   *scram_server_key_binary;	/* binary SCRAM server key */
 	ProtocolVersion min_pversion;	/* protocol version to request */
 	ProtocolVersion max_pversion;	/* protocol version to request */
 
 	/* Miscellaneous stuff */
 	int			be_pid;			/* PID of backend --- needed for cancels */
 	int			be_cancel_key_len;
-	char	   *be_cancel_key;	/* query cancellation key and its length */
+	uint8	   *be_cancel_key;	/* query cancellation key */
 	pgParameterStatus *pstatus; /* ParameterStatus data */
 	int			client_encoding;	/* encoding id */
 	bool		std_strings;	/* standard_conforming_strings */
@@ -787,9 +787,9 @@ extern int	pqPutc(char c, PGconn *conn);
 extern int	pqGets(PQExpBuffer buf, PGconn *conn);
 extern int	pqGets_append(PQExpBuffer buf, PGconn *conn);
 extern int	pqPuts(const char *s, PGconn *conn);
-extern int	pqGetnchar(char *s, size_t len, PGconn *conn);
+extern int	pqGetnchar(void *s, size_t len, PGconn *conn);
 extern int	pqSkipnchar(size_t len, PGconn *conn);
-extern int	pqPutnchar(const char *s, size_t len, PGconn *conn);
+extern int	pqPutnchar(const void *s, size_t len, PGconn *conn);
 extern int	pqGetInt(int *result, size_t bytes, PGconn *conn);
 extern int	pqPutInt(int value, size_t bytes, PGconn *conn);
 extern int	pqPutMsgStart(char msg_type, PGconn *conn);