Patch "cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode" has been added to the 6.6-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cachefiles-erofs-fix-null-deref-in-when-cachefiles-is-not-doing-ondemand-mode.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From c3d6569a43322f371e7ba0ad386112723757ac8f Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Fri, 19 Jan 2024 20:49:34 +0000
Subject: cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode

From: David Howells <dhowells@redhat.com>

commit c3d6569a43322f371e7ba0ad386112723757ac8f upstream.

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:
	 <TASK>
	 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 <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Gao Xiang <xiang@kernel.org>
cc: Chao Yu <chao@kernel.org>
cc: Yue Hu <huyue2@coolpad.com>
cc: Jeffle Xu <jefflexu@linux.alibaba.com>
cc: linux-erofs@lists.ozlabs.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/cachefiles/ondemand.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -611,6 +611,9 @@ int cachefiles_ondemand_init_object(stru
 	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


Patches currently in stable-queue which might be from dhowells@redhat.com are

queue-6.6/cachefiles-resend-an-open-request-if-the-read-reques.patch
queue-6.6/cachefiles-add-restore-command-to-recover-inflight-o.patch
queue-6.6/cachefiles-introduce-object-ondemand-state.patch
queue-6.6/cachefiles-extract-ondemand-info-field-from-cachefil.patch
queue-6.6/cachefiles-erofs-fix-null-deref-in-when-cachefiles-is-not-doing-ondemand-mode.patch