[CRIU] [PATCH 4/5] ns: Fix wrong opened net ns file

[Kirill Tkhai]

On 29.03.2017 00:38, Andrei Vagin wrote:
> On Tue, Mar 28, 2017 at 12:32:08PM +0300, Kirill Tkhai wrote:
>> On 27.03.2017 23:36, Andrei Vagin wrote:
>>> On Fri, Mar 24, 2017 at 12:35:11PM +0300, Kirill Tkhai wrote:
>>>> Since net ns is assigned after prepare_fds() and,
>>>> in common case, at the moment of open_ns_fd() call
>>>> task points to a net ns, which differs to its target
>>>> net ns, we can't get the ns from a task. So, get it
>>>> from fdstore. Also, support userns ns fds.
>>>>
>>>> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
>>>> ---
>>>>  criu/namespaces.c |   21 ++++++++++++++++++++-
>>>>  1 file changed, 20 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/criu/namespaces.c b/criu/namespaces.c
>>>> index e4555251..ee309045 100644
>>>> --- a/criu/namespaces.c
>>>> +++ b/criu/namespaces.c
>>>> @@ -556,8 +556,22 @@ static int open_ns_fd(struct file_desc *d, int *new_fd)
>>>>  	struct ns_file_info *nfi = container_of(d, struct ns_file_info, d);
>>>>  	struct pstree_item *item, *t;
>>>>  	struct ns_desc *nd = NULL;
>>>> +	struct ns_id *ns;
>>>> +	int nsfd_id, fd;
>>>>  	char path[64];
>>>> -	int fd;
>>>> +
>>>> +	for (ns = ns_ids; ns != NULL; ns = ns->next) {
>>>> +		if (ns->id != nfi->nfe->ns_id)
>>>> +			continue;
>>>> +		if (ns->nd == &user_ns_desc && (root_ns_mask & CLONE_NEWUSER))
>>>> +			nsfd_id = ns->user.nsfd_id;
>>>> +		else if (ns->nd == &net_ns_desc && (root_ns_mask & CLONE_NEWNET))
>>>> +			nsfd_id = ns->net.nsfd_id;
>>>> +		else
>>>> +			break;
>>>> +		fd = fdstore_get(nsfd_id);
>>>> +		goto check_open;
>>>> +	}
>>>>  
>>>>  	/*
>>>>  	 * Find out who can open us.
>>>> @@ -575,6 +589,10 @@ static int open_ns_fd(struct file_desc *d, int *new_fd)
>>>>  			item = t;
>>>>  			nd = &net_ns_desc;
>>>>  			break;
>>>> +		} else if (ids->user_ns_id == nfi->nfe->ns_id) {
>>>> +			item = t;
>>>> +			nd = &user_ns_desc;
>>>> +			break;
>>>
>>> hm, why do we need this code here? The first loop has to handle them,
>>> doesn't it?
>>
>> We do add net_ns and user_ns fds to fdstore only if we have
>> appropriate bit in root_ns_mask is set.
> 
> Could you add a comment about this?

Ok

>>  
>>>>  		} else if (ids->ipc_ns_id == nfi->nfe->ns_id) {
>>>>  			item = t;
>>>>  			nd = &ipc_ns_desc;
>>>> @@ -608,6 +626,7 @@ static int open_ns_fd(struct file_desc *d, int *new_fd)
>>>>  	path[sizeof(path) - 1] = '\0';
>>>>  
>>>>  	fd = open(path, nfi->nfe->flags);
>>>> +check_open:
>>>>  	if (fd < 0) {
>>>>  		pr_perror("Can't open file %s on restore", path);
>>>>  		return fd;
>>>>