[PATCH v2] keys: prevent slab cache merging for key_jar

[Mohammed EL Kadiri]

Add SLAB_NO_MERGE to key_jar to prevent the allocator from merging it
with other similarly-sized caches. This hardens struct key isolation by
ensuring dedicated slab pages.

Acked-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
Signed-off-by: Mohammed EL Kadiri <med08elkadiri@xxxxxxxxx>
---
 security/keys/key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/key.c b/security/keys/key.c
index 3bbdde778631..592b65cf8539 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -1275,7 +1275,7 @@ void __init key_init(void)
 {
 	/* allocate a slab in which we can store keys */
 	key_jar = kmem_cache_create("key_jar", sizeof(struct key),
-			0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+			0, SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_NO_MERGE, NULL);
 
 	/* add the special key types */
 	list_add_tail(&key_type_keyring.link, &key_types_list);
-- 
2.43.0