fit: Don't allow verification of images with @ nodes
When searching for a node called 'fred', any unit address appended to the
name is ignored by libfdt, meaning that 'fred' can match 'fred@1'. This
means that we cannot be sure that the node originally intended is the one
that is used.
Disallow use of nodes with unit addresses.
Update the forge test also, since it uses @ addresses.
CVE-2021-27138
Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Bruce Monroe <bruce.monroe@intel.com>
Reported-by: Arie Haenel <arie.haenel@intel.com>
Reported-by: Julien Lenoir <julien.lenoir@intel.com>
diff --git a/common/image-fit-sig.c b/common/image-fit-sig.c
index 897e04c..34ebb8e 100644
--- a/common/image-fit-sig.c
+++ b/common/image-fit-sig.c
@@ -149,6 +149,14 @@
fdt_for_each_subnode(noffset, fit, image_noffset) {
const char *name = fit_get_name(fit, noffset, NULL);
+ /*
+ * We don't support this since libfdt considers names with the
+ * name root but different @ suffix to be equal
+ */
+ if (strchr(name, '@')) {
+ err_msg = "Node name contains @";
+ goto error;
+ }
if (!strncmp(name, FIT_SIG_NODENAME,
strlen(FIT_SIG_NODENAME))) {
ret = fit_image_check_sig(fit, noffset, data,
@@ -398,9 +406,10 @@
return -EPERM;
}
-int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
- const void *sig_blob)
+static int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
+ const void *sig_blob)
{
+ const char *name = fit_get_name(fit, conf_noffset, NULL);
int noffset;
int sig_node;
int verified = 0;
@@ -408,6 +417,15 @@
bool reqd_policy_all = true;
const char *reqd_mode;
+ /*
+ * We don't support this since libfdt considers names with the
+ * name root but different @ suffix to be equal
+ */
+ if (strchr(name, '@')) {
+ printf("Configuration node '%s' contains '@'\n", name);
+ return -EPERM;
+ }
+
/* Work out what we need to verify */
sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
if (sig_node < 0) {