From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Fri, 22 Jan 2021 18:13:56 +1100
Subject: [PATCH] fs/hfsplus: Don't fetch a key beyond the end of the node
Otherwise you get a wild pointer, leading to a bunch of invalid reads.
Check it falls inside the given node.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/fs/hfsplus.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/grub-core/fs/hfsplus.c b/grub-core/fs/hfsplus.c
index 7ae66967b3a..d958c457e87 100644
--- a/grub-core/fs/hfsplus.c
+++ b/grub-core/fs/hfsplus.c
@@ -629,6 +629,10 @@ grub_hfsplus_btree_search (struct grub_hfsplus_btree *btree,
pointer = ((char *) currkey
+ grub_be_to_cpu16 (currkey->keylen)
+ 2);
+
+ if ((char *) pointer > node + btree->nodesize - 2)
+ return grub_error (GRUB_ERR_BAD_FS, "HFS+ key beyond end of node");
+
currnode = grub_be_to_cpu32 (grub_get_unaligned32 (pointer));
match = 1;
}