From 905f1272f58fbeceee4f5b66527a0b1c367f8c57 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 19 Feb 2013 17:31:08 +0000 Subject: ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up() ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up() CVE-2013-0871 BugLink: http://bugs.launchpad.net/bugs/1129192 Cleanup and preparation for the next change. signal_wake_up(resume => true) is overused. None of ptrace/jctl callers actually want to wakeup a TASK_WAKEKILL task, but they can't specify the necessary mask. Turn signal_wake_up() into signal_wake_up_state(state), reintroduce signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up() which adds __TASK_TRACED. This way ptrace_signal_wake_up() can work "inside" ptrace_request() even if the tracee doesn't have the TASK_WAKEKILL bit set. Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds (backported from commit 910ffdb18a6408e14febbb6e4b6840fd2c928c82) Conflicts: kernel/ptrace.c kernel/signal.c Signed-off-by: Luis Henriques Acked-by: Colin King Signed-off-by: Tim Gardner Signed-off-by: Willy Tarreau --- kernel/ptrace.c | 2 +- kernel/signal.c | 12 +++--------- 2 files changed, 4 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/ptrace.c b/kernel/ptrace.c index d8184b54023c..37850f9db638 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -56,7 +56,7 @@ static void ptrace_untrace(struct task_struct *child) child->signal->group_stop_count) __set_task_state(child, TASK_STOPPED); else - signal_wake_up(child, 1); + ptrace_signal_wake_up(child, true); } spin_unlock(&child->sighand->siglock); } diff --git a/kernel/signal.c b/kernel/signal.c index df993fdf43f0..b40f4f06421f 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -516,23 +516,17 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) * No need to set need_resched since signal event passing * goes through ->blocked */ -void signal_wake_up(struct task_struct *t, int resume) +void signal_wake_up_state(struct task_struct *t, unsigned int state) { - unsigned int mask; - set_tsk_thread_flag(t, TIF_SIGPENDING); - /* - * For SIGKILL, we want to wake it up in the stopped/traced/killable + * TASK_WAKEKILL also means wake it up in the stopped/traced/killable * case. We don't check t->state here because there is a race with it * executing another processor and just now entering stopped state. * By using wake_up_state, we ensure the process will wake up and * handle its death signal. */ - mask = TASK_INTERRUPTIBLE; - if (resume) - mask |= TASK_WAKEKILL; - if (!wake_up_state(t, mask)) + if (!wake_up_state(t, state | TASK_INTERRUPTIBLE)) kick_process(t); } -- cgit v1.2.3