Commit 30c5e21f authored by Baokun Li's avatar Baokun Li
Browse files

cachefiles: fix memory leak in cachefiles_add_cache() 

stable inclusion
from stable-v5.10.212
commit 43eccc5823732ba6daab2511ed32dfc545a666d8
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9HJVQ
CVE: CVE-2024-26840

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=43eccc5823732ba6daab2511ed32dfc545a666d8



--------------------------------

commit e21a2f17566cbd64926fb8f16323972f7a064444 upstream.

The following memory leak was reported after unbinding /dev/cachefiles:

==================================================================
unreferenced object 0xffff9b674176e3c0 (size 192):
  comm "cachefilesd2", pid 680, jiffies 4294881224
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc ea38a44b):
    [<ffffffff8eb8a1a5>] kmem_cache_alloc+0x2d5/0x370
    [<ffffffff8e917f86>] prepare_creds+0x26/0x2e0
    [<ffffffffc002eeef>] cachefiles_determine_cache_security+0x1f/0x120
    [<ffffffffc00243ec>] cachefiles_add_cache+0x13c/0x3a0
    [<ffffffffc0025216>] cachefiles_daemon_write+0x146/0x1c0
    [<ffffffff8ebc4a3b>] vfs_write+0xcb/0x520
    [<ffffffff8ebc5069>] ksys_write+0x69/0xf0
    [<ffffffff8f6d4662>] do_syscall_64+0x72/0x140
    [<ffffffff8f8000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
==================================================================

Put the reference count of cache_cred in cachefiles_daemon_unbind() to
fix the problem. And also put cache_cred in cachefiles_add_cache() error
branch to avoid memory leaks.

Fixes: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
CC: stable@vger.kernel.org
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240217081431.796809-1-libaokun1@huawei.com


Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
parent b05f2de3

fs/cachefiles/bind.c

+3 −0
Original line number Diff line number Diff line
@@ -245,6 +245,8 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache) 
	kmem_cache_free(cachefiles_object_jar, fsdef);

error_root_object:

	cachefiles_end_secure(cache, saved_cred);

	put_cred(cache->cache_cred);

	cache->cache_cred = NULL;

	pr_err("Failed to register: %d\n", ret);

	return ret;

}
@@ -265,6 +267,7 @@ void cachefiles_daemon_unbind(struct cachefiles_cache *cache) 


	dput(cache->graveyard);

	mntput(cache->mnt);

	put_cred(cache->cache_cred);



	kfree(cache->rootdirname);

	kfree(cache->secctx);