psql: fix startup crash caused by PSQLRC containing a tilde

bmomjian · bmomjian · commit 39d4c764da3d · 2013-04-04T12:56:25.000-04:00
'strdup' the PSQLRC environment variable value before calling a routine
that might free() it.

Backpatch to 9.2, where the bug first appeared.
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
@@ -1617,11 +1617,11 @@ session_username(void)
  * substitute '~' with HOME or '~username' with username's home dir
  *
  */
-char *
+void
 expand_tilde(char **filename)
 {
 	if (!filename || !(*filename))
-		return NULL;
+		return;
 
 	/*
 	 * WIN32 doesn't use tilde expansion for file names. Also, it uses tilde
@@ -1669,5 +1669,5 @@ expand_tilde(char **filename)
 	}
 #endif
 
-	return *filename;
+	return;
 }
diff --git a/src/bin/psql/common.h b/src/bin/psql/common.h
@@ -61,6 +61,6 @@ extern bool is_superuser(void);
 extern bool standard_strings(void);
 extern const char *session_username(void);
 
-extern char *expand_tilde(char **filename);
+extern void expand_tilde(char **filename);
 
 #endif   /* COMMON_H */
diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c
@@ -591,20 +591,21 @@ process_psqlrc(char *argv0)
 	char		rc_file[MAXPGPATH];
 	char		my_exec_path[MAXPGPATH];
 	char		etc_path[MAXPGPATH];
-	char	   *envrc;
+	char	   *envrc = getenv("PSQLRC");
 
 	find_my_exec(argv0, my_exec_path);
 	get_etc_path(my_exec_path, etc_path);
 
 	snprintf(rc_file, MAXPGPATH, "%s/%s", etc_path, SYSPSQLRC);
 	process_psqlrc_file(rc_file);
 
-	envrc = getenv("PSQLRC");
-
 	if (envrc != NULL && strlen(envrc) > 0)
 	{
-		expand_tilde(&envrc);
-		process_psqlrc_file(envrc);
+		/* might need to free() this */
+		char *envrc_alloc = pg_strdup(envrc);
+
+		expand_tilde(&envrc_alloc);
+		process_psqlrc_file(envrc_alloc);
 	}
 	else if (get_home_path(home))
 	{

Original file line number	Diff line number	Diff line change
`@@ -1617,11 +1617,11 @@ session_username(void)`
`1617`	`1617`	`* substitute '~' with HOME or '~username' with username's home dir`
`1618`	`1618`	`*`
`1619`	`1619`	`*/`
`1620`		`-char *`
	`1620`	`+void`
`1621`	`1621`	`expand_tilde(char **filename)`
`1622`	`1622`	`{`
`1623`	`1623`	`if (!filename \|\| !(*filename))`
`1624`		`- return NULL;`
	`1624`	`+ return;`
`1625`	`1625`
`1626`	`1626`	`/*`
`1627`	`1627`	`* WIN32 doesn't use tilde expansion for file names. Also, it uses tilde`
`@@ -1669,5 +1669,5 @@ expand_tilde(char **filename)`
`1669`	`1669`	`}`
`1670`	`1670`	`#endif`
`1671`	`1671`
`1672`		`- return *filename;`
	`1672`	`+ return;`
`1673`	`1673`	`}`