From c3d6569a43322f371e7ba0ad386112723757ac8f Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 19 Jan 2024 20:49:34 +0000 Subject: cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode cachefiles_ondemand_init_object() as called from cachefiles_open_file() and cachefiles_create_tmpfile() does not check if object->ondemand is set before dereferencing it, leading to an oops something like: RIP: 0010:cachefiles_ondemand_init_object+0x9/0x41 ... Call Trace: cachefiles_open_file+0xc9/0x187 cachefiles_lookup_cookie+0x122/0x2be fscache_cookie_state_machine+0xbe/0x32b fscache_cookie_worker+0x1f/0x2d process_one_work+0x136/0x208 process_scheduled_works+0x3a/0x41 worker_thread+0x1a2/0x1f6 kthread+0xca/0xd2 ret_from_fork+0x21/0x33 Fix this by making cachefiles_ondemand_init_object() return immediately if cachefiles->ondemand is NULL. Fixes: 3c5ecfe16e76 ("cachefiles: extract ondemand info field from cachefiles_object") Reported-by: Marc Dionne Signed-off-by: David Howells cc: Gao Xiang cc: Chao Yu cc: Yue Hu cc: Jeffle Xu cc: linux-erofs@lists.ozlabs.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/cachefiles/ondemand.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/cachefiles') diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 5fd74ec60bef..4ba42f1fa3b4 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -539,6 +539,9 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object) struct fscache_volume *volume = object->volume->vcookie; size_t volume_key_size, cookie_key_size, data_len; + if (!object->ondemand) + return 0; + /* * CacheFiles will firstly check the cache file under the root cache * directory. If the coherency check failed, it will fallback to -- cgit v1.2.3