Remove arbitrary restrictions on password length.

This patch started out with the goal of harmonizing various arbitrary
limits on password length, but after awhile a better idea emerged:
let's just get rid of those fixed limits.

recv_password_packet() has an arbitrary limit on the packet size,
which we don't really need, so just drop it.  (Note that this doesn't
really affect anything for MD5 or SCRAM password verification, since
those will hash the user's password to something shorter anyway.
It does matter for auth methods that require a cleartext password.)

Likewise remove the arbitrary error condition in pg_saslprep().

The remaining limits are mostly in client-side code that prompts
for passwords.  To improve those, refactor simple_prompt() so that
it allocates its own result buffer that can be made as big as
necessary.  Actually, it proves best to make a separate routine
pg_get_line() that has essentially the semantics of fgets(), except
that it allocates a suitable result buffer and hence will never
return a truncated line.  (pg_get_line has a lot of potential
applications to replace randomly-sized fgets buffers elsewhere,
but I'll leave that for another patch.)

I built pg_get_line() atop stringinfo.c, which requires moving
that code to src/common/; but that seems fine since it was a poor
fit for src/port/ anyway.

This patch is mostly mine, but it owes a good deal to Nathan Bossart
who pressed for a solution to the password length problem and
created a predecessor patch.  Also thanks to Peter Eisentraut and
Stephen Frost for ideas and discussion.

Discussion: https://postgr.es/m/[email protected]

Author: tglsfdc

contrib/oid2name/oid2name.c

@@ -12,6 +12,7 @@
 #include "catalog/pg_class_d.h"
 #include "common/connect.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "getopt_long.h"
 #include "libpq-fe.h"
 #include "pg_getopt.h"
@@ -293,8 +294,7 @@ PGconn *
 sql_conn(struct options *my_opts)
 {
 	PGconn	   *conn;
-	bool		have_password = false;
-	char		password[100];
+	char	   *password = NULL;
 	bool		new_pass;
 	PGresult   *res;
 
@@ -316,7 +316,7 @@ sql_conn(struct options *my_opts)
 		keywords[2] = "user";
 		values[2] = my_opts->username;
 		keywords[3] = "password";
-		values[3] = have_password ? password : NULL;
+		values[3] = password;
 		keywords[4] = "dbname";
 		values[4] = my_opts->dbname;
 		keywords[5] = "fallback_application_name";
@@ -336,11 +336,10 @@ sql_conn(struct options *my_opts)
 
 		if (PQstatus(conn) == CONNECTION_BAD &&
 			PQconnectionNeedsPassword(conn) &&
-			!have_password)
+			!password)
 		{
 			PQfinish(conn);
-			simple_prompt("Password: ", password, sizeof(password), false);
-			have_password = true;
+			password = simple_prompt("Password: ", false);
 			new_pass = true;
 		}
 	} while (new_pass);

contrib/vacuumlo/vacuumlo.c

@@ -24,6 +24,7 @@
 #include "catalog/pg_class_d.h"
 #include "common/connect.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "getopt_long.h"
 #include "libpq-fe.h"
 #include "pg_getopt.h"
@@ -69,15 +70,11 @@ vacuumlo(const char *database, const struct _param *param)
 	int			i;
 	bool		new_pass;
 	bool		success = true;
-	static bool have_password = false;
-	static char password[100];
+	static char *password = NULL;
 
 	/* Note: password can be carried over from a previous call */
-	if (param->pg_prompt == TRI_YES && !have_password)
-	{
-		simple_prompt("Password: ", password, sizeof(password), false);
-		have_password = true;
-	}
+	if (param->pg_prompt == TRI_YES && !password)
+		password = simple_prompt("Password: ", false);
 
 	/*
 	 * Start the connection.  Loop until we have a password if requested by
@@ -97,7 +94,7 @@ vacuumlo(const char *database, const struct _param *param)
 		keywords[2] = "user";
 		values[2] = param->pg_user;
 		keywords[3] = "password";
-		values[3] = have_password ? password : NULL;
+		values[3] = password;
 		keywords[4] = "dbname";
 		values[4] = database;
 		keywords[5] = "fallback_application_name";
@@ -115,12 +112,11 @@ vacuumlo(const char *database, const struct _param *param)
 
 		if (PQstatus(conn) == CONNECTION_BAD &&
 			PQconnectionNeedsPassword(conn) &&
-			!have_password &&
+			!password &&
 			param->pg_prompt != TRI_NO)
 		{
 			PQfinish(conn);
-			simple_prompt("Password: ", password, sizeof(password), false);
-			have_password = true;
+			password = simple_prompt("Password: ", false);
 			new_pass = true;
 		}
 	} while (new_pass);

src/backend/libpq/auth.c

@@ -698,7 +698,7 @@ recv_password_packet(Port *port)
 	}
 
 	initStringInfo(&buf);
-	if (pq_getmessage(&buf, 1000))	/* receive password */
+	if (pq_getmessage(&buf, 0)) /* receive password */
 	{
 		/* EOF - pq_getmessage already logged a suitable message */
 		pfree(buf.data);

src/bin/initdb/initdb.c

@@ -67,6 +67,7 @@
 #include "common/file_utils.h"
 #include "common/logging.h"
 #include "common/restricted_token.h"
+#include "common/string.h"
 #include "common/username.h"
 #include "fe_utils/string_utils.h"
 #include "getaddrinfo.h"
@@ -1481,23 +1482,25 @@ setup_auth(FILE *cmdfd)
 static void
 get_su_pwd(void)
 {
-	char		pwd1[100];
-	char		pwd2[100];
+	char	   *pwd1;
 
 	if (pwprompt)
 	{
 		/*
 		 * Read password from terminal
 		 */
+		char	   *pwd2;
+
 		printf("\n");
 		fflush(stdout);
-		simple_prompt("Enter new superuser password: ", pwd1, sizeof(pwd1), false);
-		simple_prompt("Enter it again: ", pwd2, sizeof(pwd2), false);
+		pwd1 = simple_prompt("Enter new superuser password: ", false);
+		pwd2 = simple_prompt("Enter it again: ", false);
 		if (strcmp(pwd1, pwd2) != 0)
 		{
 			fprintf(stderr, _("Passwords didn't match.\n"));
 			exit(1);
 		}
+		free(pwd2);
 	}
 	else
 	{
@@ -1510,15 +1513,15 @@ get_su_pwd(void)
 		 * for now.
 		 */
 		FILE	   *pwf = fopen(pwfilename, "r");
-		int			i;
 
 		if (!pwf)
 		{
 			pg_log_error("could not open file \"%s\" for reading: %m",
 						 pwfilename);
 			exit(1);
 		}
-		if (!fgets(pwd1, sizeof(pwd1), pwf))
+		pwd1 = pg_get_line(pwf);
+		if (!pwd1)
 		{
 			if (ferror(pwf))
 				pg_log_error("could not read password from file \"%s\": %m",
@@ -1530,12 +1533,10 @@ get_su_pwd(void)
 		}
 		fclose(pwf);
 
-		i = strlen(pwd1);
-		while (i > 0 && (pwd1[i - 1] == '\r' || pwd1[i - 1] == '\n'))
-			pwd1[--i] = '\0';
+		(void) pg_strip_crlf(pwd1);
 	}
 
-	superuser_password = pg_strdup(pwd1);
+	superuser_password = pwd1;
 }
 
 /*

src/bin/pg_basebackup/streamutil.c

@@ -22,6 +22,7 @@
 #include "common/fe_memutils.h"
 #include "common/file_perm.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "datatype/timestamp.h"
 #include "port/pg_bswap.h"
 #include "pqexpbuffer.h"
@@ -49,8 +50,7 @@ char	   *dbuser = NULL;
 char	   *dbport = NULL;
 char	   *dbname = NULL;
 int			dbgetpassword = 0;	/* 0=auto, -1=never, 1=always */
-static bool have_password = false;
-static char password[100];
+static char *password = NULL;
 PGconn	   *conn = NULL;
 
 /*
@@ -150,20 +150,21 @@ GetConnection(void)
 	}
 
 	/* If -W was given, force prompt for password, but only the first time */
-	need_password = (dbgetpassword == 1 && !have_password);
+	need_password = (dbgetpassword == 1 && !password);
 
 	do
 	{
 		/* Get a new password if appropriate */
 		if (need_password)
 		{
-			simple_prompt("Password: ", password, sizeof(password), false);
-			have_password = true;
+			if (password)
+				free(password);
+			password = simple_prompt("Password: ", false);
 			need_password = false;
 		}
 
 		/* Use (or reuse, on a subsequent connection) password if we have it */
-		if (have_password)
+		if (password)
 		{
 			keywords[i] = "password";
 			values[i] = password;

src/bin/pg_dump/pg_backup_db.c

@@ -18,6 +18,7 @@
 #endif
 
 #include "common/connect.h"
+#include "common/string.h"
 #include "dumputils.h"
 #include "fe_utils/string_utils.h"
 #include "parallel.h"
@@ -122,7 +123,6 @@ _connectDB(ArchiveHandle *AH, const char *reqdb, const char *requser)
 	const char *newdb;
 	const char *newuser;
 	char	   *password;
-	char		passbuf[100];
 	bool		new_pass;
 
 	if (!reqdb)
@@ -141,10 +141,7 @@ _connectDB(ArchiveHandle *AH, const char *reqdb, const char *requser)
 	password = AH->savedPassword;
 
 	if (AH->promptPassword == TRI_YES && password == NULL)
-	{
-		simple_prompt("Password: ", passbuf, sizeof(passbuf), false);
-		password = passbuf;
-	}
+		password = simple_prompt("Password: ", false);
 
 	initPQExpBuffer(&connstr);
 	appendPQExpBufferStr(&connstr, "dbname=");
@@ -191,8 +188,9 @@ _connectDB(ArchiveHandle *AH, const char *reqdb, const char *requser)
 
 			if (AH->promptPassword != TRI_NO)
 			{
-				simple_prompt("Password: ", passbuf, sizeof(passbuf), false);
-				password = passbuf;
+				if (password && password != AH->savedPassword)
+					free(password);
+				password = simple_prompt("Password: ", false);
 			}
 			else
 				fatal("connection needs password");
@@ -201,6 +199,9 @@ _connectDB(ArchiveHandle *AH, const char *reqdb, const char *requser)
 		}
 	} while (new_pass);
 
+	if (password && password != AH->savedPassword)
+		free(password);
+
 	/*
 	 * We want to remember connection's actual password, whether or not we got
 	 * it by prompting.  So we don't just store the password variable.
@@ -242,7 +243,6 @@ ConnectDatabase(Archive *AHX,
 {
 	ArchiveHandle *AH = (ArchiveHandle *) AHX;
 	char	   *password;
-	char		passbuf[100];
 	bool		new_pass;
 
 	if (AH->connection)
@@ -251,10 +251,8 @@ ConnectDatabase(Archive *AHX,
 	password = AH->savedPassword;
 
 	if (prompt_password == TRI_YES && password == NULL)
-	{
-		simple_prompt("Password: ", passbuf, sizeof(passbuf), false);
-		password = passbuf;
-	}
+		password = simple_prompt("Password: ", false);
+
 	AH->promptPassword = prompt_password;
 
 	/*
@@ -293,8 +291,7 @@ ConnectDatabase(Archive *AHX,
 			prompt_password != TRI_NO)
 		{
 			PQfinish(AH->connection);
-			simple_prompt("Password: ", passbuf, sizeof(passbuf), false);
-			password = passbuf;
+			password = simple_prompt("Password: ", false);
 			new_pass = true;
 		}
 	} while (new_pass);
@@ -309,6 +306,9 @@ ConnectDatabase(Archive *AHX,
 	PQclear(ExecuteSqlQueryForSingleRow((Archive *) AH,
 										ALWAYS_SECURE_SEARCH_PATH_SQL));
 
+	if (password && password != AH->savedPassword)
+		free(password);
+
 	/*
 	 * We want to remember connection's actual password, whether or not we got
 	 * it by prompting.  So we don't just store the password variable.

src/bin/pg_dump/pg_dumpall.c

@@ -21,6 +21,7 @@
 #include "common/connect.h"
 #include "common/file_utils.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "dumputils.h"
 #include "fe_utils/string_utils.h"
 #include "getopt_long.h"
@@ -1643,14 +1644,10 @@ connectDatabase(const char *dbname, const char *connection_string,
 	const char **keywords = NULL;
 	const char **values = NULL;
 	PQconninfoOption *conn_opts = NULL;
-	static bool have_password = false;
-	static char password[100];
+	static char *password = NULL;
 
-	if (prompt_password == TRI_YES && !have_password)
-	{
-		simple_prompt("Password: ", password, sizeof(password), false);
-		have_password = true;
-	}
+	if (prompt_password == TRI_YES && !password)
+		password = simple_prompt("Password: ", false);
 
 	/*
 	 * Start the connection.  Loop until we have a password if requested by
@@ -1730,7 +1727,7 @@ connectDatabase(const char *dbname, const char *connection_string,
 			values[i] = pguser;
 			i++;
 		}
-		if (have_password)
+		if (password)
 		{
 			keywords[i] = "password";
 			values[i] = password;
@@ -1757,12 +1754,11 @@ connectDatabase(const char *dbname, const char *connection_string,
 
 		if (PQstatus(conn) == CONNECTION_BAD &&
 			PQconnectionNeedsPassword(conn) &&
-			!have_password &&
+			!password &&
 			prompt_password != TRI_NO)
 		{
 			PQfinish(conn);
-			simple_prompt("Password: ", password, sizeof(password), false);
-			have_password = true;
+			password = simple_prompt("Password: ", false);
 			new_pass = true;
 		}
 	} while (new_pass);

src/bin/pgbench/pgbench.c

@@ -59,6 +59,7 @@
 
 #include "common/int.h"
 #include "common/logging.h"
+#include "common/string.h"
 #include "fe_utils/cancel.h"
 #include "fe_utils/conditional.h"
 #include "getopt_long.h"
@@ -1174,8 +1175,7 @@ doConnect(void)
 {
 	PGconn	   *conn;
 	bool		new_pass;
-	static bool have_password = false;
-	static char password[100];
+	static char *password = NULL;
 
 	/*
 	 * Start the connection.  Loop until we have a password if requested by
@@ -1195,7 +1195,7 @@ doConnect(void)
 		keywords[2] = "user";
 		values[2] = login;
 		keywords[3] = "password";
-		values[3] = have_password ? password : NULL;
+		values[3] = password;
 		keywords[4] = "dbname";
 		values[4] = dbName;
 		keywords[5] = "fallback_application_name";
@@ -1215,11 +1215,10 @@ doConnect(void)
 
 		if (PQstatus(conn) == CONNECTION_BAD &&
 			PQconnectionNeedsPassword(conn) &&
-			!have_password)
+			!password)
 		{
 			PQfinish(conn);
-			simple_prompt("Password: ", password, sizeof(password), false);
-			have_password = true;
+			password = simple_prompt("Password: ", false);
 			new_pass = true;
 		}
 	} while (new_pass);