An overlay with a label entry in the `__symbols__` table without a
matching fragment that contains an `__overlay__` is not an error. This
matches the behavior of the dtc libfdt implementation[1].
This edge case was triggered by:
1. Enabling CONFIG_OF_OVERLAY_LIVE this adds a `__symbols__` table to
device trees compiled by barebox.
2. Passing the barebox devicetree via TF-A to OP-TEE that adds overlay
fragments to the barebox device tree.
3. Enabling CONFIG_OPTEE_APPLY_OVERLAY and applying the same DT again as
a DT overlay. The DT in this case was expanded by OP-TEE with overlay
fragments (and still contains the __symbol__ table with entries that
do not reference the OP-TEE fragments).
[1]: 5c715a4 ("fdtoverlay: Ignore symbols in overlays which don't apply to the
target tree")
Fixes: 6553d2c2a5e3 ("of: overlay: avoid potential null pointer exception")
Signed-off-by: Stefan Kerkmann <[email protected]>
---
drivers/of/overlay.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 4ce45513ea..a1df9c3c79 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -99,27 +99,37 @@ static int of_overlay_apply(struct device_node *target,
static char *of_overlay_fix_path(struct device_node *root,
struct device_node *overlay, const char *path)
{
+ struct device_node *overlay_node;
struct device_node *fragment;
struct device_node *target;
const char *path_tail;
const char *prefix;
+ size_t prefix_len;
fragment = of_find_node_by_path_from(overlay, path);
while ((fragment = of_get_parent(fragment)) != NULL) {
- if (of_get_child_by_name(fragment, "__overlay__"))
+ overlay_node = of_get_child_by_name(fragment, "__overlay__");
+ if (overlay_node != NULL)
break;
}
+
if (!fragment) {
- pr_info("could not find __overlay__ node\n");
+ pr_debug("could not find __overlay__ node for %s\n", path);
+ return NULL;
+ }
+
+ prefix = overlay_node->full_name;
+ prefix_len = str_has_prefix(path, prefix);
+ if (!prefix_len || !strchr("/", path[prefix_len])) {
+ pr_debug("%s is not below %pOF\n", path, overlay_node);
return NULL;
}
target = find_target(root, fragment, false);
if (!target)
- return NULL;
+ return ERR_PTR(-EINVAL);
- prefix = of_get_child_by_name(fragment, "__overlay__")->full_name;
- path_tail = path + strlen(prefix);
+ path_tail = path + prefix_len;
return basprintf("%pOF%s", target, path_tail);
}
@@ -152,8 +162,10 @@ static int of_overlay_apply_symbols(struct device_node
*root,
old_path = of_property_get_value(prop);
new_path = of_overlay_fix_path(root, overlay, old_path);
+ if (IS_ERR(new_path))
+ return PTR_ERR(new_path);
if (!new_path)
- return -EINVAL;
+ continue;
pr_debug("add symbol %s with new path %s\n",
prop->name, new_path);
--
2.47.3
