* [PATCH 6.6 250/267] cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode
[not found] <20240619125606.345939659@linuxfoundation.org>
@ 2024-06-19 12:56 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2024-06-19 12:56 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Marc Dionne, David Howells,
Gao Xiang, Chao Yu, Yue Hu, Jeffle Xu, linux-erofs, netfs,
linux-fsdevel
6.6-stable review patch. If anyone has any objections, please let me know.
------------------
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
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