Commit ca97d6ae authored by Zizhi Wo's avatar Zizhi Wo
Browse files

cachefiles: Set object to close if ondemand_id < 0 in copen 

mainline inclusion
from mainline-v6.10-rc4
commit 4f8703fb3482f92edcfd31661857b16fec89c2c0
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4f8703fb3482f92edcfd31661857b16fec89c2c0



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

If copen is maliciously called in the user mode, it may delete the request
corresponding to the random id. And the request may have not been read yet.

Note that when the object is set to reopen, the open request will be done
with the still reopen state in above case. As a result, the request
corresponding to this object is always skipped in select_req function, so
the read request is never completed and blocks other process.

Fix this issue by simply set object to close if its id < 0 in copen.

Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-11-libaokun@huaweicloud.com


Acked-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarJia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent d8422a0e

fs/cachefiles/ondemand.c

+6 −1
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) 
	xas_store(&xas, NULL);

	xa_unlock(&cache->reqs);



	info = req->object->ondemand;

	/* fail OPEN request if copen format is invalid */

	ret = kstrtol(psize, 0, &size);

	if (ret) {
@@ -201,7 +202,6 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) 
		goto out;

	}



	info = req->object->ondemand;

	spin_lock(&info->lock);

	/*

	 * The anonymous fd was closed before copen ? Fail the request.
@@ -241,6 +241,11 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) 
	wake_up_all(&cache->daemon_pollwq);



out:

	spin_lock(&info->lock);

	/* Need to set object close to avoid reopen status continuing */

	if (info->ondemand_id == CACHEFILES_ONDEMAND_ID_CLOSED)

		cachefiles_ondemand_set_object_close(req->object);

	spin_unlock(&info->lock);

	complete(&req->done);

	return ret;

}