[patch 26/54] tty: fix leakage of -ERESTARTSYS to userland

Chris Wright
2007-06-08T07:33:43Z

[-- Attachment #1: tty-fix-leakage-of-erestartsys-to-userland.patch --]
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-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Oleg Nesterov <oleg@tv-sign.ru>

Spotted by Satoru Takeuchi.

kill_pgrp(task_pgrp(current)) sends the signal to the current's thread
group, but can choose any sub-thread as a target for signal_wake_up().
This means that job_control() and tty_check_change() may return
-ERESTARTSYS without signal_pending().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

drivers/char/n_tty.c | 1 +
drivers/char/tty_io.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)

--- linux-2.6.21.4.orig/drivers/char/n_tty.c
+++ linux-2.6.21.4/drivers/char/n_tty.c
@@ -1191,6 +1191,7 @@ static int job_control(struct tty_struct
is_current_pgrp_orphaned())
return -EIO;
kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+ set_thread_flag(TIF_SIGPENDING);
return -ERESTARTSYS;
}
}
--- linux-2.6.21.4.orig/drivers/char/tty_io.c
+++ linux-2.6.21.4/drivers/char/tty_io.c
@@ -1121,7 +1121,8 @@ int tty_check_change(struct tty_struct *
return 0;
if (is_current_pgrp_orphaned())
return -EIO;
- (void) kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+ kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+ set_thread_flag(TIF_SIGPENDING);
return -ERESTARTSYS;
}

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