aleph/lkl_linux
1
0
Fork 0
mirror of https://github.com/lkl/linux.git synced 2025-12-19 16:13:19 +09:00
Code Issues Packages Projects Releases Wiki Activity

keys: change keyctl_session_to_parent() to use task_work_add()

Browse Source 
Change keyctl_session_to_parent() to use task_work_add() and move
key_replace_session_keyring() logic into task_work->func().

Note that we do task_work_cancel() before task_work_add() to ensure that
only one work can be pending at any time.  This is important, we must not
allow user-space to abuse the parent's ->task_works list.

The callback, replace_session_keyring(), checks PF_EXITING.  I guess this
is not really needed but looks better.

As a side effect, this fixes the (unlikely) race.  The callers of
key_replace_session_keyring() and keyctl_session_to_parent() lack the
necessary barriers, the parent can miss the request.

Now we can remove task_struct->replacement_session_keyring and related
code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Smith <dsmith@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Oleg Nesterov
2012-05-11 10:59:08 +10:00
committed by Al Viro
parent 4d1d61a6b2
commit 413cd3d9ab
4 changed files with 46 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/key.h
View File

@@ -33,6 +33,8 @@ typedef uint32_t key_perm_t;
struct key;
#define key_replace_session_keyring() do { } while (0)
#ifdef CONFIG_KEYS
#undef KEY_DEBUGGING
@@ -308,9 +310,6 @@ static inline bool key_is_instantiated(const struct key *key)
#ifdef CONFIG_SYSCTL
extern ctl_table key_sysctls[];
#endif
extern void key_replace_session_keyring(void);
/*
* the userspace interface
*/
@@ -334,7 +333,6 @@ extern void key_init(void);
#define key_fsuid_changed(t) do { } while(0)
#define key_fsgid_changed(t) do { } while(0)
#define key_init() do { } while(0)
#define key_replace_session_keyring() do { } while(0)
#endif /* CONFIG_KEYS */
#endif /* __KERNEL__ */