From 85bca3c05b6cca31625437eedf2060e846c4bbad Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Fri, 10 Dec 2021 13:44:13 +0000
Subject: [PATCH] dm btree: add a defensive bounds check to insert_at()
Git-commit: 85bca3c05b6cca31625437eedf2060e846c4bbad
Patch-mainline: v5.17-rc1
References: jsc#PED-2765
Corrupt metadata could trigger an out of bounds write.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/persistent-data/dm-btree.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c
index 0703ca7a7d9a..5ce64e93aae7 100644
--- a/drivers/md/persistent-data/dm-btree.c
+++ b/drivers/md/persistent-data/dm-btree.c
@@ -81,14 +81,16 @@ void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
}
static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
- uint64_t key, void *value)
- __dm_written_to_disk(value)
+ uint64_t key, void *value)
+ __dm_written_to_disk(value)
{
uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
+ uint32_t max_entries = le32_to_cpu(node->header.max_entries);
__le64 key_le = cpu_to_le64(key);
if (index > nr_entries ||
- index >= le32_to_cpu(node->header.max_entries)) {
+ index >= max_entries ||
+ nr_entries >= max_entries) {
DMERR("too many entries in btree node for insert");
__dm_unbless_for_disk(value);
return -ENOMEM;
--
2.35.3