Documentation/security/credentials.txt

17      - Immutable credentials.
18      - Accessing task credentials.
19      - Accessing another task's credentials.
20      - Altering credentials.
21      - Managing credentials.
40 	- Tasks
41 	- Files/inodes
42 	- Sockets
43 	- Message queues
44 	- Shared memory segments
45 	- Semaphores
46 	- Keys
64      the same set as in (2) - in standard UNIX files, for instance, this is the
91      group list for when it is acting upon a file - which are quite separate
118 	 file may supply more than one ACL.
123 	 ('read', 'write' and 'execute' - whatever those map to for the object
212 	Per-thread keying
213 	Per-process keyring
214 	Per-session keyring
233      This is a socket-based approach to credential management for networking
300 To alter anything in the cred struct, the copy-and-replace principle must be
309 attachment to process-specific keyrings in the requesting process as the
314 ---------------------
332 --------------------------
336 - which simplifies things greatly.  It can just call:
386 ------------------------------------
398 	void foo(struct task_struct *t, struct foo_data *f)
404 		f->uid = tcred->uid;
405 		f->gid = tcred->gid;
406 		f->groups = get_group_info(tcred->groups);
431 	__task_cred(task)->uid
432 	__task_cred(task)->euid
445 where 'member' is a non-pointer member of the cred struct.  For instance:
455 --------------------
466 this locks current->cred_replace_mutex and then allocates and constructs a
487 commit the new credentials to current->cred, it will release
488 current->cred_replace_mutex to allow ptrace() to take place, and it will notify
491 This function is guaranteed to return 0, so that it can be tail-called at the
506 This releases the lock on current->cred_replace_mutex that prepare_creds() got
519 			return -ENOMEM;
521 		new->suid = suid;
533 --------------------
560 'f_uid' and 'f_gid'.  Code that used to access file->f_uid and file->f_gid
561 should now access file->f_cred->fsuid and file->f_cred->fsgid.