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Never call putenv() with data on the stack.

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Even though we are using putenv() here to remove items from the
environment, there is no guarantee that putenv() doesn't add the
argument to the environment anyway. In that case, we have to make sure
that it doesn't go away. We also don't want a memory leak, so keep a
list of things we unputenv()ed around, so we can reuse things.

Thanks to Poul-Henning Kamp for pointing out this problem.

# Conflicts:
#	src/process.c
This commit is contained in:
Guus Sliepen 2015-05-03 20:06:12 +02:00
parent 0e8e53b4ce
commit cadbf587a0
1 changed files with 39 additions and 11 deletions
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50
src/script.c
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@ -26,6 +26,43 @@
#include "script.h"
#include "xalloc.h"
#ifdef HAVE_PUTENV
static void unputenv(const char *p) {
const char *e = strchr(p, '=');
if(!e)
return;
int len = e - p;
#ifndef HAVE_UNSETENV
#ifdef HAVE_MINGW
// Windows requires putenv("FOO=") to unset %FOO%
len++;
#endif
#endif
char var[len + 1];
strncpy(var, p, len);
var[len] = 0;
#ifdef HAVE_UNSETENV
unsetenv(var);
#else
// We must keep what we putenv() around in memory.
// To do this without memory leaks, keep things in a list and reuse if possible.
static list_t list = {};
for list_each(char, data, &list) {
if(!strcmp(data, var)) {
putenv(data);
return;
}
}
char *data = xstrdup(var);
list_insert_tail(&list, data);
putenv(data);
#endif
}
#else
static void putenv(const char *p) {}
static void unputenv(const char *p) {}
#endif
bool execute_script(const char *name, char **envp) {
#ifdef HAVE_SYSTEM
char scriptname[PATH_MAX];
@ -67,12 +104,10 @@ bool execute_script(const char *name, char **envp) {
logger(DEBUG_STATUS, LOG_INFO, "Executing script %s", name);
#ifdef HAVE_PUTENV
/* Set environment */
for(int i = 0; envp[i]; i++)
putenv(envp[i]);
#endif
if(scriptinterpreter)
xasprintf(&command, "%s \"%s\"", scriptinterpreter, scriptname);
@ -85,15 +120,8 @@ bool execute_script(const char *name, char **envp) {
/* Unset environment */
for(int i = 0; envp[i]; i++) {
char *e = strchr(envp[i], '=');
if(e) {
char p[e - envp[i] + 1];
strncpy(p, envp[i], e - envp[i]);
p[e - envp[i]] = '\0';
putenv(p);
}
}
for(int i = 0; envp[i]; i++)
unputenv(envp[i]);
if(status != -1) {
#ifdef WEXITSTATUS