pbx.c: prevent potential crash from recursive replace()

Recurisve usage of replace() resulted in corruption of the
temporary string storage and potential crash.  By changing
the string to be allocated separtely per instance, this is
eliminated.

ASTERISK-23650 #comment Reported by: Roel van Meer
ASTERISK-23650 #close

Review: https://reviewboard.asterisk.org/r/3539/
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Merged revisions 414214 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 414215 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 414216 from http://svn.asterisk.org/svn/asterisk/branches/12

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@414217 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/funcs/func_strings.c b/funcs/func_strings.c
index ac889ec04855a08520b5e8e7b2a6fdc643631357..c3d768384ad5b8ef05767688260f593982ab73dd 100644 (file)
--- a/funcs/func_strings.c
+++ b/funcs/func_strings.c
@@ -798,7 +798,7 @@ static int replace(struct ast_channel *chan, const char *cmd, char *data, struct
                AST_APP_ARG(replace);
        );
        char *strptr, *varsubst;
-       struct ast_str *str = ast_str_thread_get(&result_buf, 16);
+       RAII_VAR(struct ast_str *, str, ast_str_create(16), ast_free);
        char find[256]; /* Only 256 characters possible */
        char replace[2] = "";
        size_t unused;