Don't access free memory after unloading a module. Bugzilla #4168.

2 files changed, 19 insertions, 1 deletions

diff --git a/hw/xfree86/dummylib/xalloc.c b/hw/xfree86/dummylib/xalloc.c
index a78250f2b..7131dc5e6 100644
--- a/hw/xfree86/dummylib/xalloc.c
+++ b/hw/xfree86/dummylib/xalloc.c
@@ -94,3 +94,19 @@ Xstrdup(const char *s)
 	strcpy(sd, s);
     return sd;
 }
+
+char *
+XNFstrdup(const char *s)
+{
+    char *sd;
+    size_t len;
+
+    if (s == NULL)
+	return NULL;
+    
+    len = strlen(s) + 1;
+    sd = (char *)XNFalloc(len);
+    strlcpy(sd, s, len);
+    return sd;
+}
+
diff --git a/hw/xfree86/loader/loader.c b/hw/xfree86/loader/loader.c
index 30f151a4c..4c904128e 100644
--- a/hw/xfree86/loader/loader.c
+++ b/hw/xfree86/loader/loader.c
@@ -818,7 +818,9 @@ static void
 AppendSymbol(symlist * list, const char *sym)
 {
     list->list = xnfrealloc(list->list, (list->num + 1) * sizeof(char **));
-    list->list[list->num] = sym;
+    /* copy the symbol, since it comes from a module 
+       that can be unloaded later */
+    list->list[list->num] = xnfstrdup(sym);
     list->num++;
 }