From: Diederik de Groot <dkgroot@talon.nl>
Date: Sat, 5 Jan 2019 17:14:26 +0000 (+0100)
Subject: RAII: Change order or variables in clang version
X-Git-Tag: 16.2.0-rc1~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d2c182b6ab63b8c39597f657ff7168c7d3424c8c;p=thirdparty%2Fasterisk.git

RAII: Change order or variables in clang version

This prevents use-after-scope issues when unwinding the stack,
which happens in reverse order. The varname variable needs to
remain alive for the destruction to be able to access it.
Issue was found using clang + address-sanitizer.

ASTERISK-28232 #close

Change-Id: I00811c34ae910836a5fb6d22304528aef92624db
---

diff --git a/include/asterisk/utils.h b/include/asterisk/utils.h
index c0cce98ae2..4dc406db7f 100644
--- a/include/asterisk/utils.h
+++ b/include/asterisk/utils.h
@@ -786,10 +786,10 @@ char *ast_utils_which(const char *binary, char *fullpath, size_t fullpath_size);
 typedef void (^_raii_cleanup_block_t)(void);
 static inline void _raii_cleanup_block(_raii_cleanup_block_t *b) { (*b)(); }
 
-#define RAII_VAR(vartype, varname, initval, dtor)                                                                \
-    _raii_cleanup_block_t _raii_cleanup_ ## varname __attribute__((cleanup(_raii_cleanup_block),unused)) = NULL; \
-    __block vartype varname = initval;                                                                           \
-    _raii_cleanup_ ## varname = ^{ {(void)dtor(varname);} }
+#define RAII_VAR(vartype, varname, initval, dtor)                                                              \
+    __block vartype varname = initval;                                                                         \
+    _raii_cleanup_block_t _raii_cleanup_ ## varname __attribute__((cleanup(_raii_cleanup_block),unused)) =     \
+        ^{ {(void)dtor(varname);} };
 
 #elif defined(__GNUC__)