1 files changed, 34 insertions, 11 deletions

diff --git a/missing/setproctitle.c b/missing/setproctitle.c
index f90886671c..5b2dfa65ce 100644
--- a/missing/setproctitle.c
+++ b/missing/setproctitle.c
@@ -87,7 +87,30 @@ static char **argv1_addr = NULL;
 #endif
 
 #if ALLOCATE_ENVIRON
+/* system_environ is the value of environ before we allocate a custom buffer.
+ *
+ * We use this to restore environ in ruby_free_proctitle.
+ */
+static char **system_environ = NULL;
+/* orig_environ is the buffer we allocate for environ.
+ *
+ * We use this to free this buffer in ruby_free_proctitle. When we add new
+ * environment variables using setenv, the system may change environ to a
+ * different buffer and will not free the original buffer, so we need to hold
+ * onto this so we can free it in ruby_free_proctitle.
+ *
+ * We must not free any of the contents because it may change if the system
+ * updates existing environment variables.
+ */
 static char **orig_environ = NULL;
+/* alloc_environ is a copy of orig_environ.
+ *
+ * We use this to free all the original string copies that were in orig_environ.
+ * Since environ could be changed to point to strings allocated by the system
+ * if environment variables are updated, so we need this to point to the
+ * original strings.
+ */
+static char **alloc_environ = NULL;
 #endif
 
 void
@@ -112,6 +135,9 @@ compat_init_setproctitle(int argc, char *argv[])
 	/* Fail if we can't allocate room for the new environment */
 	for (i = 0; envp[i] != NULL; i++);
 
+	system_environ = environ;
+
+	alloc_environ = xcalloc(i + 1, sizeof(*environ));
 	orig_environ = environ = xcalloc(i + 1, sizeof(*environ));
 	if (environ == NULL) {
 		environ = envp;	/* put it back */
@@ -140,8 +166,8 @@ compat_init_setproctitle(int argc, char *argv[])
 	argv_env_len = lastenvp - argv[0];
 
 	for (i = 0; envp[i] != NULL; i++)
-		environ[i] = ruby_strdup(envp[i]);
-	environ[i] = NULL;
+		alloc_environ[i] = environ[i] = ruby_strdup(envp[i]);
+	alloc_environ[i] = environ[i] = NULL;
 #endif /* SPT_REUSEARGV */
 }
 
@@ -153,16 +179,13 @@ ruby_free_proctitle(void)
 
 	if (!orig_environ) return; /* environ is allocated by OS */
 
-	/* ruby_setenv could allocate a new environ, so we need to free orig_environ
-	 * in that case. */
-	if (environ != orig_environ) {
-		for (int i = 0; orig_environ[i] != NULL; i++) {
-			xfree(orig_environ[i]);
-		}
-
-		xfree(orig_environ);
-		orig_environ = NULL;
+	for (int i = 0; alloc_environ[i] != NULL; i++) {
+		xfree(alloc_environ[i]);
 	}
+	xfree(alloc_environ);
+	xfree(orig_environ);
+
+	environ = system_environ;
 #endif
 }