[PATCH v8 04/13] lib/bootconfig: increment xbc_node_num after node init succeeds

Josh Law
2026-03-18T15:59:30Z

Move the xbc_node_num increment to after xbc_init_node() so a failed
init does not leave a partially initialized node counted in the array.

If xbc_init_node() fails on a data offset at the boundary of a
maximum-size bootconfig, the pre-incremented count causes subsequent
tree verification and traversal to consider the uninitialized node as
valid, potentially leading to an out-of-bounds read or unpredictable
boot behavior.

Signed-off-by: Josh Law <objecting@objecting.org>
---
lib/bootconfig.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index ca668ead1db6..6b899e24189c 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -429,9 +429,10 @@ static struct xbc_node * __init xbc_add_node(char *data, uint16_t flag)
if (xbc_node_num == XBC_NODE_MAX)
return NULL;

- node = &xbc_nodes[xbc_node_num++];
+ node = &xbc_nodes[xbc_node_num];
if (xbc_init_node(node, data, flag) < 0)
return NULL;
+ xbc_node_num++;

return node;
}
--
2.34.1