WSL2-Linux-Kernel/security
Peter Zijlstra 24ec839c43 [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>
2006-12-08 08:28:38 -08:00
..
keys [PATCH] lockdep: name some old style locks 2006-12-07 08:39:36 -08:00
selinux [PATCH] tty: ->signal->tty locking 2006-12-08 08:28:38 -08:00
Kconfig [PATCH] LSM: remove BSD secure level security module 2006-09-29 09:18:10 -07:00
Makefile [PATCH] LSM: remove BSD secure level security module 2006-09-29 09:18:10 -07:00
capability.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
commoncap.c [PATCH] pidspace: is_init() 2006-09-29 09:18:12 -07:00
dummy.c SELinux: Fix SA selection semantics 2006-12-02 21:21:34 -08:00
inode.c [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
root_plug.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
security.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00