[PATCH] cmd: extension: Fix possible null pointer dereference

[Kory Maincent]

From: "Kory Maincent (TI.com)" <kory.maincent at bootlin.com>

Add a null check for extension_list before calling alist_get_ptr() to
prevent a potential null pointer dereference. If extension_get_list()
returns NULL, alist_get_ptr() would attempt to dereference it, leading
to undefined behavior.

The fix ensures both extension_list and its first element are checked
before proceeding with the list operation.

Closes: https://lists.denx.de/pipermail/u-boot/2025-November/602892.html
Fixes: 2d12958ee71b ("boot: Remove legacy extension board support")
Signed-off-by: Kory Maincent (TI.com) <kory.maincent at bootlin.com>
---
 cmd/extension_board.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/extension_board.c b/cmd/extension_board.c
index 86e4795ba8a..1b92be82611 100644
--- a/cmd/extension_board.c
+++ b/cmd/extension_board.c
@@ -99,7 +99,7 @@ static int do_extension_list(struct cmd_tbl *cmdtp, int flag,
 	int i = 0;
 
 	extension_list = extension_get_list();
-	if (!alist_get_ptr(extension_list, 0)) {
+	if (!extension_list || !alist_get_ptr(extension_list, 0)) {
 		printf("No extension registered - Please run \"extension scan\"\n");
 		return CMD_RET_SUCCESS;
 	}
-- 
2.43.0