diff options
| author | Baokun Li <libaokun1@huawei.com> | 2024-05-22 14:42:58 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-05-29 14:03:29 +0300 |
| commit | 0fc75c5940fa634d84e64c93bfc388e1274ed013 (patch) | |
| tree | e68b86d26437b3201171f482dd7097b9d5ca3467 /fs/cachefiles | |
| parent | cc5ac966f26193ab185cc43d64d9f1ae998ccb6e (diff) | |
| download | linux-0fc75c5940fa634d84e64c93bfc388e1274ed013.tar.xz | |
cachefiles: remove requests from xarray during flushing requests
Even with CACHEFILES_DEAD set, we can still read the requests, so in the
following concurrency the request may be used after it has been freed:
mount | daemon_thread1 | daemon_thread2
------------------------------------------------------------
cachefiles_ondemand_init_object
cachefiles_ondemand_send_req
REQ_A = kzalloc(sizeof(*req) + data_len)
wait_for_completion(&REQ_A->done)
cachefiles_daemon_read
cachefiles_ondemand_daemon_read
// close dev fd
cachefiles_flush_reqs
complete(&REQ_A->done)
kfree(REQ_A)
xa_lock(&cache->reqs);
cachefiles_ondemand_select_req
req->msg.opcode != CACHEFILES_OP_READ
// req use-after-free !!!
xa_unlock(&cache->reqs);
xa_destroy(&cache->reqs)
Hence remove requests from cache->reqs when flushing them to avoid
accessing freed requests.
Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-3-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/cachefiles')
| -rw-r--r-- | fs/cachefiles/daemon.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 6465e2574230..ccb7b707ea4b 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -159,6 +159,7 @@ static void cachefiles_flush_reqs(struct cachefiles_cache *cache) xa_for_each(xa, index, req) { req->error = -EIO; complete(&req->done); + __xa_erase(xa, index); } xa_unlock(xa); |