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authorOleg Nesterov <oleg@redhat.com>2012-05-11 10:59:08 +1000
committerAl Viro <viro@zeniv.linux.org.uk>2012-05-23 22:11:23 -0400
commit413cd3d9abeaef590e5ce00564f7a443165db238 (patch)
treefc7d254053793a95d1470f7c9eafb782d8cf91d6 /security/keys/internal.h
parent4d1d61a6b203d957777d73fcebf19d90b038b5b2 (diff)
keys: change keyctl_session_to_parent() to use task_work_add()
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>
Diffstat (limited to 'security/keys/internal.h')
-rw-r--r--security/keys/internal.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/security/keys/internal.h b/security/keys/internal.h
index f711b094ed41..3dcbf86b0d31 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -14,6 +14,7 @@
#include <linux/sched.h>
#include <linux/key-type.h>
+#include <linux/task_work.h>
#ifdef __KDEBUG
#define kenter(FMT, ...) \
@@ -148,6 +149,7 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
#define KEY_LOOKUP_FOR_UNLINK 0x04
extern long join_session_keyring(const char *name);
+extern void key_change_session_keyring(struct task_work *twork);
extern struct work_struct key_gc_work;
extern unsigned key_gc_delay;