[CRIU] [PATCH] files-reg: fix /proc/<pid>/* ownership for linkat restore

[Dmitry Safonov]

On 12/17/2015 03:58 PM, Pavel Emelyanov wrote:
> On 12/17/2015 03:25 PM, Dmitry Safonov wrote:
>> After linkat_hard with setfsuid permissions of files in
>> /proc/<pid>/* changes to root because of pid_getattr @ fs/proc/base.c
>> will fail to check has_pid_permissions() in ptrace_may_access()
> Wait, the  __ptrace_may_access starts with
>
>          if (same_thread_group(task, current))
>                  return 0;
>
> so writing to self is always granted.
Seems so, will check it.
>
>> Fix it with PR_SET_DUMPABLE.
>>
>> Cc: Andrew Vagin <avagin at virtuozzo.com>
>> Signed-off-by: Dmitry Safonov <dsafonov at odin.com>
>> ---
>>   files-reg.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/files-reg.c b/files-reg.c
>> index 425dc04..082e46c 100644
>> --- a/files-reg.c
>> +++ b/files-reg.c
>> @@ -6,6 +6,7 @@
>>   #include <sys/mman.h>
>>   #include <sys/types.h>
>>   #include <sys/stat.h>
>> +#include <sys/prctl.h>
>>   #include <sys/vfs.h>
>>   #include <ctype.h>
>>   
>> @@ -1100,6 +1101,7 @@ static int linkat_hard(int odir, char *opath, int ndir, char *npath, uid_t owner
>>   			 */
>>   	}
>>   	errno = errno_save;
>> +	prctl(PR_SET_DUMPABLE, 1, 0);
>>   
>>   	return ret;
>>   }
>>


-- 
Regards,
Dmitry Safonov