Check return value of strdup() in libpq connection option parsing.

An out-of-memory in most of these would lead to strange behavior, like
connecting to a different database than intended, but some would lead to
an outright segfault.

Alex Shulgin and me. Backpatch to all supported versions.

Author: hlinnaka

src/interfaces/libpq/fe-connect.c

@@ -333,7 +333,7 @@ static int	connectDBStart(PGconn *conn);
 static int	connectDBComplete(PGconn *conn);
 static PGPing internal_ping(PGconn *conn);
 static PGconn *makeEmptyPGconn(void);
-static void fillPGconn(PGconn *conn, PQconninfoOption *connOptions);
+static bool fillPGconn(PGconn *conn, PQconninfoOption *connOptions);
 static void freePGconn(PGconn *conn);
 static void closePGconn(PGconn *conn);
 static PQconninfoOption *conninfo_init(PQExpBuffer errorMessage);
@@ -585,7 +585,11 @@ PQconnectStartParams(const char *const * keywords,
 	/*
 	 * Move option values into conn structure
 	 */
-	fillPGconn(conn, connOptions);
+	if (!fillPGconn(conn, connOptions))
+	{
+		PQconninfoFree(connOptions);
+		return conn;
+	}
 
 	/*
 	 * Free the option info - all is in conn now
@@ -665,19 +669,19 @@ PQconnectStart(const char *conninfo)
 	return conn;
 }
 
-static void
+/*
+ * Move option values into conn structure
+ *
+ * Don't put anything cute here --- intelligence should be in
+ * connectOptions2 ...
+ *
+ * Returns true on success. On failure, returns false and sets error message.
+ */
+static bool
 fillPGconn(PGconn *conn, PQconninfoOption *connOptions)
 {
 	const internalPQconninfoOption *option;
 
-	/*
-	 * Move option values into conn structure
-	 *
-	 * Don't put anything cute here --- intelligence should be in
-	 * connectOptions2 ...
-	 *
-	 * XXX: probably worth checking strdup() return value here...
-	 */
 	for (option = PQconninfoOptions; option->keyword; option++)
 	{
 		const char *tmp = conninfo_getval(connOptions, option->keyword);
@@ -688,9 +692,22 @@ fillPGconn(PGconn *conn, PQconninfoOption *connOptions)
 
 			if (*connmember)
 				free(*connmember);
-			*connmember = tmp ? strdup(tmp) : NULL;
+			if (tmp)
+			{
+				*connmember = strdup(tmp);
+				if (*connmember == NULL)
+				{
+					printfPQExpBuffer(&conn->errorMessage,
+									  libpq_gettext("out of memory\n"));
+					return false;
+				}
+			}
+			else
+				*connmember = NULL;
 		}
 	}
+
+	return true;
 }
 
 /*
@@ -723,7 +740,12 @@ connectOptions1(PGconn *conn, const char *conninfo)
 	/*
 	 * Move option values into conn structure
 	 */
-	fillPGconn(conn, connOptions);
+	if (!fillPGconn(conn, connOptions))
+	{
+		conn->status = CONNECTION_BAD;
+		PQconninfoFree(connOptions);
+		return false;
+	}
 
 	/*
 	 * Free the option info - all is in conn now
@@ -753,6 +775,8 @@ connectOptions2(PGconn *conn)
 		if (conn->dbName)
 			free(conn->dbName);
 		conn->dbName = strdup(conn->pguser);
+		if (!conn->dbName)
+			goto oom_error;
 	}
 
 	/*
@@ -765,7 +789,12 @@ connectOptions2(PGconn *conn)
 		conn->pgpass = PasswordFromFile(conn->pghost, conn->pgport,
 										conn->dbName, conn->pguser);
 		if (conn->pgpass == NULL)
+		{
 			conn->pgpass = strdup(DefaultPassword);
+			if (!conn->pgpass)
+				goto oom_error;
+
+		}
 		else
 			conn->dot_pgpass_used = true;
 	}
@@ -823,7 +852,11 @@ connectOptions2(PGconn *conn)
 #endif
 	}
 	else
+	{
 		conn->sslmode = strdup(DefaultSSLMode);
+		if (!conn->sslmode)
+			goto oom_error;
+	}
 
 	/*
 	 * Resolve special "auto" client_encoding from the locale
@@ -833,6 +866,8 @@ connectOptions2(PGconn *conn)
 	{
 		free(conn->client_encoding_initial);
 		conn->client_encoding_initial = strdup(pg_encoding_to_char(pg_get_encoding_from_locale(NULL, true)));
+		if (!conn->client_encoding_initial)
+			goto oom_error;
 	}
 
 	/*
@@ -843,6 +878,12 @@ connectOptions2(PGconn *conn)
 	conn->options_valid = true;
 
 	return true;
+
+oom_error:
+	conn->status = CONNECTION_BAD;
+	printfPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext("out of memory\n"));
+	return false;
 }
 
 /*
@@ -937,6 +978,8 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
 			if (conn->dbName)
 				free(conn->dbName);
 			conn->dbName = strdup(dbName);
+			if (!conn->dbName)
+				goto oom_error;
 		}
 	}
 
@@ -949,41 +992,53 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
 		if (conn->pghost)
 			free(conn->pghost);
 		conn->pghost = strdup(pghost);
+		if (!conn->pghost)
+			goto oom_error;
 	}
 
 	if (pgport && pgport[0] != '\0')
 	{
 		if (conn->pgport)
 			free(conn->pgport);
 		conn->pgport = strdup(pgport);
+		if (!conn->pgport)
+			goto oom_error;
 	}
 
 	if (pgoptions && pgoptions[0] != '\0')
 	{
 		if (conn->pgoptions)
 			free(conn->pgoptions);
 		conn->pgoptions = strdup(pgoptions);
+		if (!conn->pgoptions)
+			goto oom_error;
 	}
 
 	if (pgtty && pgtty[0] != '\0')
 	{
 		if (conn->pgtty)
 			free(conn->pgtty);
 		conn->pgtty = strdup(pgtty);
+		if (!conn->pgtty)
+			goto oom_error;
 	}
 
 	if (login && login[0] != '\0')
 	{
 		if (conn->pguser)
 			free(conn->pguser);
 		conn->pguser = strdup(login);
+		if (!conn->pguser)
+			goto oom_error;
 	}
 
 	if (pwd && pwd[0] != '\0')
 	{
 		if (conn->pgpass)
 			free(conn->pgpass);
 		conn->pgpass = strdup(pwd);
+		if (!conn->pgpass)
+			goto oom_error;
 	}
 
 	/*
@@ -999,6 +1054,12 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
 		(void) connectDBComplete(conn);
 
 	return conn;
+
+oom_error:
+	conn->status = CONNECTION_BAD;
+	printfPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext("out of memory\n"));
+	return conn;
 }
 
 
@@ -3760,7 +3821,16 @@ ldapServiceLookup(const char *purl, PQconninfoOption *options,
 				if (strcmp(options[i].keyword, optname) == 0)
 				{
 					if (options[i].val == NULL)
+					{
 						options[i].val = strdup(optval);
+						if (!options[i].val)
+						{
+							printfPQExpBuffer(errorMessage,
+											libpq_gettext("out of memory\n"));
+							free(result);
+							return 3;
+						}
+					}
 					found_keyword = true;
 					break;
 				}
@@ -3983,6 +4053,13 @@ parseServiceFile(const char *serviceFile,
 					{
 						if (options[i].val == NULL)
 							options[i].val = strdup(val);
+						if (!options[i].val)
+						{
+							printfPQExpBuffer(errorMessage,
+											libpq_gettext("out of memory\n"));
+							fclose(f);
+							return 3;
+						}
 						found_keyword = true;
 						break;
 					}
@@ -4402,6 +4479,14 @@ conninfo_array_parse(const char *const * keywords, const char *const * values,
 								if (options[k].val)
 									free(options[k].val);
 								options[k].val = strdup(str_option->val);
+								if (!options[k].val)
+								{
+									printfPQExpBuffer(errorMessage,
+													  libpq_gettext("out of memory\n"));
+									PQconninfoFree(options);
+									PQconninfoFree(dbname_options);
+									return NULL;
+								}
 								break;
 							}
 						}
@@ -4596,20 +4681,22 @@ conninfo_uri_parse_options(PQconninfoOption *options, const char *uri,
 {
 	int			prefix_len;
 	char	   *p;
-	char	   *buf = strdup(uri);		/* need a modifiable copy of the input
-										 * URI */
-	char	   *start = buf;
+	char	   *buf;
+	char	   *start;
 	char		prevchar = '\0';
 	char	   *user = NULL;
 	char	   *host = NULL;
 	bool		retval = false;
 
+	/* need a modifiable copy of the input URI */
+	buf = strdup(uri);
 	if (buf == NULL)
 	{
 		printfPQExpBuffer(errorMessage,
 						  libpq_gettext("out of memory\n"));
 		return false;
 	}
+	start = buf;
 
 	/* Skip the URI prefix */
 	prefix_len = uri_prefix_length(uri);
@@ -4951,15 +5038,17 @@ conninfo_uri_parse_params(char *params,
 static char *
 conninfo_uri_decode(const char *str, PQExpBuffer errorMessage)
 {
-	char	   *buf = malloc(strlen(str) + 1);
-	char	   *p = buf;
+	char	   *buf;
+	char	   *p;
 	const char *q = str;
 
+	buf = malloc(strlen(str) + 1);
 	if (buf == NULL)
 	{
 		printfPQExpBuffer(errorMessage, libpq_gettext("out of memory\n"));
 		return NULL;
 	}
+	p = buf;
 
 	for (;;)
 	{
@@ -5104,7 +5193,6 @@ conninfo_storeval(PQconninfoOption *connOptions,
 	else
 	{
 		value_copy = strdup(value);
-
 		if (value_copy == NULL)
 		{
 			printfPQExpBuffer(errorMessage, libpq_gettext("out of memory\n"));
@@ -5672,6 +5760,12 @@ PasswordFromFile(char *hostname, char *port, char *dbname, char *username)
 		ret = strdup(t);
 		fclose(fp);
 
+		if (!ret)
+		{
+			/* Out of memory. XXX: an error message would be nice. */
+			return NULL;
+		}
+
 		/* De-escape password. */
 		for (p1 = p2 = ret; *p1 != ':' && *p1 != '\0'; ++p1, ++p2)
 		{