Re: [PATCH AUTOSEL 5.3 15/71] rbd: fix response length parameter for encoded strings

Sasha Levin
2019-10-08T21:29:47Z

On Tue, Oct 01, 2019 at 07:15:49PM +0200, Ilya Dryomov wrote:
>On Tue, Oct 1, 2019 at 6:39 PM Sasha Levin <sashal@kernel.org> wrote:
>>
>> From: Dongsheng Yang <dongsheng.yang@easystack.cn>
>>
>> [ Upstream commit 5435d2069503e2aa89c34a94154f4f2fa4a0c9c4 ]
>>
>> rbd_dev_image_id() allocates space for length but passes a smaller
>> value to rbd_obj_method_sync(). rbd_dev_v2_object_prefix() doesn't
>> allocate space for length. Fix both to be consistent.
>>
>> Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
>> Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
>> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>> drivers/block/rbd.c | 10 ++++++----
>> 1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
>> index c8fb886aebd4e..69db7385c8df5 100644
>> --- a/drivers/block/rbd.c
>> +++ b/drivers/block/rbd.c
>> @@ -5669,17 +5669,20 @@ static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)
>>
>> static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
>> {
>> + size_t size;
>> void *reply_buf;
>> int ret;
>> void *p;
>>
>> - reply_buf = kzalloc(RBD_OBJ_PREFIX_LEN_MAX, GFP_KERNEL);
>> + /* Response will be an encoded string, which includes a length */
>> + size = sizeof(__le32) + RBD_OBJ_PREFIX_LEN_MAX;
>> + reply_buf = kzalloc(size, GFP_KERNEL);
>> if (!reply_buf)
>> return -ENOMEM;
>>
>> ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
>> &rbd_dev->header_oloc, "get_object_prefix",
>> - NULL, 0, reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
>> + NULL, 0, reply_buf, size);
>> dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
>> if (ret < 0)
>> goto out;
>> @@ -6696,7 +6699,6 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
>> dout("rbd id object name is %s\n", oid.name);
>>
>> /* Response will be an encoded string, which includes a length */
>> -
>> size = sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX;
>> response = kzalloc(size, GFP_NOIO);
>> if (!response) {
>> @@ -6708,7 +6710,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
>>
>> ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
>> "get_id", NULL, 0,
>> - response, RBD_IMAGE_ID_LEN_MAX);
>> + response, size);
>> dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
>> if (ret == -ENOENT) {
>> image_id = kstrdup("", GFP_KERNEL);
>
>Hi Sasha,
>
>This patch just made things consistent, there was no bug here. I don't
>think it should be backported.

I'll drop it, thanks!

--
Thanks,
Sasha