x86: Fix do_go_exec() - const argv[]
Commit 54841ab50c20d6fa6c9cc3eb826989da3a22d934 made the argv parameter
to do_go_exec() const but did not allow for the fact that argv[-1] is
set to point to the global data structure and relies on argv being non-
const.
With this patch, do_go_exec() creates a new copy of the argv array with
an extra element to store global data pointer rather than simply
clobbering an arbitrary memory location.
diff --git a/arch/i386/lib/board.c b/arch/i386/lib/board.c
index 684cdb8..93f910b 100644
--- a/arch/i386/lib/board.c
+++ b/arch/i386/lib/board.c
@@ -431,15 +431,30 @@
for (;;);
}
-unsigned long do_go_exec (ulong (*entry)(int, char *[]), int argc, char * const argv[])
+unsigned long do_go_exec (ulong (*entry)(int, char * const []), int argc, char * const argv[])
{
- /*
- * x86 does not use a dedicated register to pass the pointer
- * to the global_data
- */
- argv[-1] = (char *)gd;
+ unsigned long ret = 0;
+ char **argv_tmp;
- return (entry) (argc, argv);
+ /*
+ * x86 does not use a dedicated register to pass the pointer to
+ * the global_data, so it is instead passed as argv[-1]. By using
+ * argv[-1], the called 'Application' can use the contents of
+ * argv natively. However, to safely use argv[-1] a new copy of
+ * argv is needed with the extra element
+ */
+ argv_tmp = malloc(sizeof(char *) * (argc + 1));
+
+ if (argv_tmp) {
+ argv_tmp[0] = (char *)gd;
+
+ memcpy(&argv_tmp[1], argv, (size_t)(sizeof(char *) * argc));
+
+ ret = (entry) (argc, &argv_tmp[1]);
+ free(argv_tmp);
+ }
+
+ return ret;
}
void setup_pcat_compatibility(void)