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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2006-12-08 05:36:04 -0500
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-08 11:28:38 -0500
commit24ec839c431eb79bb8f6abc00c4e1eb3b8c4d517 (patch)
tree2ff478b1925159eeac007913c2a8f19d5f5e6010 /kernel/auditsc.c
parent562f9c574e0707f9159a729ea41faf53b221cd30 (diff)
[PATCH] tty: ->signal->tty locking
Fix the locking of signal->tty. Use ->sighand->siglock to protect ->signal->tty; this lock is already used by most other members of ->signal/->sighand. And unless we are 'current' or the tasklist_lock is held we need ->siglock to access ->signal anyway. (NOTE: sys_unshare() is broken wrt ->sighand locking rules) Note that tty_mutex is held over tty destruction, so while holding tty_mutex any tty pointer remains valid. Otherwise the lifetime of ttys are governed by their open file handles. This leaves some holes for tty access from signal->tty (or any other non file related tty access). It solves the tty SLAB scribbles we were seeing. (NOTE: the change from group_send_sig_info to __group_send_sig_info needs to be examined by someone familiar with the security framework, I think it is safe given the SEND_SIG_PRIV from other __group_send_sig_info invocations) [schwidefsky@de.ibm.com: 3270 fix] [akpm@osdl.org: various post-viro fixes] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Roland McGrath <roland@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jan Kara <jack@ucw.cz> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/auditsc.c')
-rw-r--r--kernel/auditsc.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 40722e26de98..b6cb802fbcd1 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -826,10 +826,12 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
826 context->return_code); 826 context->return_code);
827 827
828 mutex_lock(&tty_mutex); 828 mutex_lock(&tty_mutex);
829 read_lock(&tasklist_lock);
829 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name) 830 if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
830 tty = tsk->signal->tty->name; 831 tty = tsk->signal->tty->name;
831 else 832 else
832 tty = "(none)"; 833 tty = "(none)";
834 read_unlock(&tasklist_lock);
833 audit_log_format(ab, 835 audit_log_format(ab,
834 " a0=%lx a1=%lx a2=%lx a3=%lx items=%d" 836 " a0=%lx a1=%lx a2=%lx a3=%lx items=%d"
835 " ppid=%d pid=%d auid=%u uid=%u gid=%u" 837 " ppid=%d pid=%d auid=%u uid=%u gid=%u"