linux-kernel - [PATCH 2/3] pids: immprove get_task_pid() to fix the unsafe sys_wait4()->task

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20090116055518.GA28128@redhat.com>
Date:	Fri, 16 Jan 2009 06:55:18 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Pavel Emelyanov <xemul@...nvz.org>,
	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] pids: immprove get_task_pid() to fix the unsafe
	sys_wait4()->task_pgrp()

sys_wait4() does get_pid(task_pgrp(current)), this is not safe. We can
add rcu lock/unlock around, but we already have get_task_pid() which can
be improved to handle the special pids in more reliable manner.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>

--- CUR/kernel/pid.c~SP_2_wait	2009-01-12 23:07:49.000000000 +0100
+++ CUR/kernel/pid.c	2009-01-16 02:54:26.000000000 +0100
@@ -403,6 +403,8 @@ struct pid *get_task_pid(struct task_str
 {
 	struct pid *pid;
 	rcu_read_lock();
+	if (type != PIDTYPE_PID)
+		task = task->group_leader;
 	pid = get_pid(task->pids[type].pid);
 	rcu_read_unlock();
 	return pid;
--- CUR/kernel/exit.c~SP_2_wait	2009-01-12 23:07:49.000000000 +0100
+++ CUR/kernel/exit.c	2009-01-16 02:51:48.000000000 +0100
@@ -1811,7 +1811,7 @@ asmlinkage long sys_wait4(pid_t upid, in
 		pid = find_get_pid(-upid);
 	} else if (upid == 0) {
 		type = PIDTYPE_PGID;
-		pid = get_pid(task_pgrp(current));
+		pid = get_task_pid(current, PIDTYPE_PGID);
 	} else /* upid > 0 */ {
 		type = PIDTYPE_PID;
 		pid = find_get_pid(upid);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/