Re: [LTP] [PATCH] Writing "deny" to the /proc/[pid]/setgroups file before writing to /proc/[pid]/gid_map.

[Yuan Sun <sunyuan3@huawei.com>]

Hi Jan,
     Many thanks for adding commit message.
Best regard.
     Yuan

On 2015/7/16 16:56, Jan Stancek wrote:
>
>
>
> ----- Original Message -----
>> From: "Yuan Sun" <sunyuan3@huawei.com>
>> To: jstancek@redhat.com
>> Cc: ltp-list@lists.sourceforge.net
>> Sent: Friday, 10 July, 2015 7:16:25 PM
>> Subject: [PATCH] Writing "deny" to the /proc/[pid]/setgroups file before writing to /proc/[pid]/gid_map.
> I added commit message to make it more clear why setgroups is disabled,
> and pushed the patch.
>
> Regards,
> Jan
>
>> Signed-off-by: Yuan Sun <sunyuan3@huawei.com>
>> ---
>>   testcases/kernel/containers/userns/userns03.c | 77
>>   +++++++++++++--------------
>>   1 file changed, 38 insertions(+), 39 deletions(-)
>>
>> diff --git a/testcases/kernel/containers/userns/userns03.c
>> b/testcases/kernel/containers/userns/userns03.c
>> index f724967..4e12ff1 100644
>> --- a/testcases/kernel/containers/userns/userns03.c
>> +++ b/testcases/kernel/containers/userns/userns03.c
>> @@ -23,7 +23,8 @@
>>    * ID-outside-ns is defined with respect to the user namespace of the
>>    process
>>    * opening the file.
>>    *
>> - * GID check is skipped if setgroups is allowed, see kernel commits:
>> + * The string "deny" would be written to /proc/self/setgroups before GID
>> + * check if setgroups is allowed, see kernel commits:
>>    *
>>    *   commit 9cc46516ddf497ea16e8d7cb986ae03a0f6b92f8
>>    *   Author: Eric W. Biederman <ebiederm@xmission.com>
>> @@ -87,17 +88,11 @@ static int child_fn2(void)
>>   	uid = geteuid();
>>   	gid = getegid();
>>   
>> -	if (uid != CHILD2UID) {
>> -		printf("unexpected uid=%d\n", uid);
>> +	if (uid != CHILD2UID || gid != CHILD2GID) {
>> +		printf("unexpected uid=%d gid=%d\n", uid, gid);
>>   		exit_val = 1;
>>   	}
>>   
>> -	if (setgroupstag == false) {
>> -		if (gid != CHILD2GID) {
>> -			printf("unexpected: gid=%d\n", gid);
>> -			exit_val = 1;
>> -		}
>> -	}
>>   	/*Get the uid parameters of the child_fn2 process.*/
>>   	SAFE_FILE_SCANF(NULL, "/proc/self/uid_map", "%d %d %d", &idinsidens,
>>   		&idoutsidens, &length);
>> @@ -127,27 +122,25 @@ static int child_fn2(void)
>>   		exit_val = 1;
>>   	}
>>   
>> -	if (setgroupstag == false) {
>> -		sprintf(cpid1gidpath, "/proc/%d/gid_map", cpid1);
>> -		SAFE_FILE_SCANF(NULL, "/proc/self/gid_map", "%d %d %d",
>> -			 &idinsidens, &idoutsidens, &length);
>> +	sprintf(cpid1gidpath, "/proc/%d/gid_map", cpid1);
>> +	SAFE_FILE_SCANF(NULL, "/proc/self/gid_map", "%d %d %d",
>> +		 &idinsidens, &idoutsidens, &length);
>>   
>> -		if (idinsidens != CHILD2GID || idoutsidens != parentgid) {
>> -			printf("child_fn2 checks /proc/cpid2/gid_map:\n");
>> -			printf("unexpected: idinsidens=%d idoutsidens=%d\n",
>> -				idinsidens, idoutsidens);
>> -			exit_val = 1;
>> -		}
>> +	if (idinsidens != CHILD2GID || idoutsidens != parentgid) {
>> +		printf("child_fn2 checks /proc/cpid2/gid_map:\n");
>> +		printf("unexpected: idinsidens=%d idoutsidens=%d\n",
>> +			idinsidens, idoutsidens);
>> +		exit_val = 1;
>> +	}
>>   
>> -		SAFE_FILE_SCANF(NULL, cpid1gidpath, "%d %d %d", &idinsidens,
>> -			&idoutsidens, &length);
>> +	SAFE_FILE_SCANF(NULL, cpid1gidpath, "%d %d %d", &idinsidens,
>> +		&idoutsidens, &length);
>>   
>> -		if (idinsidens != CHILD1GID || idoutsidens != CHILD2GID) {
>> -			printf("child_fn1 checks /proc/cpid1/gid_map:\n");
>> -			printf("unexpected: idinsidens=%d idoutsidens=%d\n",
>> -				idinsidens, idoutsidens);
>> -			exit_val = 1;
>> -		}
>> +	if (idinsidens != CHILD1GID || idoutsidens != CHILD2GID) {
>> +		printf("child_fn1 checks /proc/cpid1/gid_map:\n");
>> +		printf("unexpected: idinsidens=%d idoutsidens=%d\n",
>> +			idinsidens, idoutsidens);
>> +		exit_val = 1;
>>   	}
>>   
>>   	TST_SAFE_CHECKPOINT_WAKE(NULL, 0);
>> @@ -162,17 +155,11 @@ static void cleanup(void)
>>   
>>   static void setup(void)
>>   {
>> -	char read_buf[BUFSIZ];
>> -
>>   	check_newuser();
>>   	tst_tmpdir();
>>   	TST_CHECKPOINT_INIT(NULL);
>> -	if (access("/proc/self/setgroups", F_OK) == 0) {
>> -		SAFE_FILE_SCANF(cleanup, "/proc/self/setgroups", "%s",
>> -			read_buf);
>> -		if (strcmp(read_buf, "deny") == 0)
>> -			setgroupstag = false;
>> -	}
>> +	if (access("/proc/self/setgroups", F_OK) == 0)
>> +		setgroupstag = false;
>>   }
>>   
>>   static int updatemap(int cpid, bool type, int idnum, int parentmappid)
>> @@ -198,8 +185,10 @@ static int updatemap(int cpid, bool type, int idnum, int
>> parentmappid)
>>   int main(int argc, char *argv[])
>>   {
>>   	pid_t cpid2;
>> +	char path[BUFSIZ];
>>   	int cpid1status, cpid2status;
>>   	int lc;
>> +	int fd;
>>   
>>   	tst_parse_opts(argc, argv, NULL, NULL);
>>   	setup();
>> @@ -222,13 +211,23 @@ int main(int argc, char *argv[])
>>   			tst_brkm(TBROK | TERRNO, cleanup,
>>   				"cpid2 clone failed");
>>   
>> +		if (setgroupstag == false) {
>> +			sprintf(path, "/proc/%d/setgroups", cpid1);
>> +			fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
>> +			SAFE_WRITE(cleanup, 1, fd, "deny", 4);
>> +			SAFE_CLOSE(cleanup, fd);
>> +
>> +			sprintf(path, "/proc/%d/setgroups", cpid2);
>> +			fd = SAFE_OPEN(cleanup, path, O_WRONLY, 0644);
>> +			SAFE_WRITE(cleanup, 1, fd, "deny", 4);
>> +			SAFE_CLOSE(cleanup, fd);
>> +		}
>> +
>>   		updatemap(cpid1, UID_MAP, CHILD1UID, parentuid);
>>   		updatemap(cpid2, UID_MAP, CHILD2UID, parentuid);
>>   
>> -		if (setgroupstag == false) {
>> -			updatemap(cpid1, GID_MAP, CHILD1GID, parentuid);
>> -			updatemap(cpid2, GID_MAP, CHILD2GID, parentuid);
>> -		}
>> +		updatemap(cpid1, GID_MAP, CHILD1GID, parentuid);
>> +		updatemap(cpid2, GID_MAP, CHILD2GID, parentuid);
>>   
>>   		TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 1);
>>   
>> --
>> 1.9.1
>>
>>
> .
>


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