From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226dyWzUsEm7n8Vhy69XGGTitEm9c8kRbX3cpri0FunfdobDDBWCGtg9DqO3yB/dKbOcHbWf ARC-Seal: i=1; a=rsa-sha256; t=1518708378; cv=none; d=google.com; s=arc-20160816; b=rZtVSPAPlWedoEep1U954pywuK7saFWvN1wDgrn+q7QslbUnVrgBG55f4ngetLCcKv kU+IzuJwTkjLbMkIhsT4UCVvw6JsqpgvklhE1SpdaDNTqctcfjPIde7hfFipNrUjA24E DfRJE2/tB6I3iHOPcsw7DPpCbf5GbyUGq7WA7SoOIkERuJB0+/wREt/pkJclGSUFJsla o0bk/Gl3m1BuiaRFBZv74/8jQtbgOPBvPhKK2GmBTTU2kDSiZOummDlTwXKmF0m1z7H1 QH/k0tw5ja/+6BmSHAPZIs8SNjnOSOvLh115pbrL0JFA6w7uZRIT6rJKuFVfqRGsEn3S XnQQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=Y5e9XP6ICzUshcvXq4PfnUGO02WztvKoH7U/d3dcv9E=; b=eop1GUF4AJ6DXNtEmBAbDTeLzRpSoihB7EfaTFrkHommuHX6FiOppsDz3f5fG1hP/W JDbzUC5fJDWTzTnTXcv67GAqMC5WzkUckafg/An/nsRb37nGZ3v4R54Z4cbDykNQzlFv o2To3Vtli3zMqF6ZpADZP9MHluXVrcyT7bPPybFuNTBZd1SLrqbVIuOGi2F7pNdaBMrz g+YKsuxPTHc42GQa8UukuFxNRfFvVyGpVAEbvnHYc0Js0Vi5ZG9t/x5Jms3du1SeEC06 R+OZ8B9Z3LUKXEALsPKkn7Qk2tffSZYFG0oI7u/j352JdbZS/dCNmXegraEvz3fT6XJU GHcg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Biggers , Dmitry Vyukov , Alexey Dobriyan , Thomas Gleixner , John Stultz Subject: [PATCH 4.9 07/88] posix-timer: Properly check sigevent->sigev_notify Date: Thu, 15 Feb 2018 16:16:34 +0100 Message-Id: <20180215151223.559084730@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180215151222.437136975@linuxfoundation.org> References: <20180215151222.437136975@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1592480739009494259?= X-GMAIL-MSGID: =?utf-8?q?1592481156458680786?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit cef31d9af908243421258f1df35a4a644604efbe upstream. timer_create() specifies via sigevent->sigev_notify the signal delivery for the new timer. The valid modes are SIGEV_NONE, SIGEV_SIGNAL, SIGEV_THREAD and (SIGEV_SIGNAL | SIGEV_THREAD_ID). The sanity check in good_sigevent() is only checking the valid combination for the SIGEV_THREAD_ID bit, i.e. SIGEV_SIGNAL, but if SIGEV_THREAD_ID is not set it accepts any random value. This has no real effects on the posix timer and signal delivery code, but it affects show_timer() which handles the output of /proc/$PID/timers. That function uses a string array to pretty print sigev_notify. The access to that array has no bound checks, so random sigev_notify cause access beyond the array bounds. Add proper checks for the valid notify modes and remove the SIGEV_THREAD_ID masking from various code pathes as SIGEV_NONE can never be set in combination with SIGEV_THREAD_ID. Reported-by: Eric Biggers Reported-by: Dmitry Vyukov Reported-by: Alexey Dobriyan Signed-off-by: Thomas Gleixner Cc: John Stultz Signed-off-by: Greg Kroah-Hartman --- kernel/time/posix-timers.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -507,17 +507,22 @@ static struct pid *good_sigevent(sigeven { struct task_struct *rtn = current->group_leader; - if ((event->sigev_notify & SIGEV_THREAD_ID ) && - (!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) || - !same_thread_group(rtn, current) || - (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) + switch (event->sigev_notify) { + case SIGEV_SIGNAL | SIGEV_THREAD_ID: + rtn = find_task_by_vpid(event->sigev_notify_thread_id); + if (!rtn || !same_thread_group(rtn, current)) + return NULL; + /* FALLTHRU */ + case SIGEV_SIGNAL: + case SIGEV_THREAD: + if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX) + return NULL; + /* FALLTHRU */ + case SIGEV_NONE: + return task_pid(rtn); + default: return NULL; - - if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) && - ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX))) - return NULL; - - return task_pid(rtn); + } } void posix_timers_register_clock(const clockid_t clock_id, @@ -745,8 +750,7 @@ common_timer_get(struct k_itimer *timr, /* interval timer ? */ if (iv.tv64) cur_setting->it_interval = ktime_to_timespec(iv); - else if (!hrtimer_active(timer) && - (timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) + else if (!hrtimer_active(timer) && timr->it_sigev_notify != SIGEV_NONE) return; now = timer->base->get_time(); @@ -757,7 +761,7 @@ common_timer_get(struct k_itimer *timr, * expiry is > now. */ if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING || - (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) + timr->it_sigev_notify == SIGEV_NONE)) timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv); remaining = __hrtimer_expires_remaining_adjusted(timer, now); @@ -767,7 +771,7 @@ common_timer_get(struct k_itimer *timr, * A single shot SIGEV_NONE timer must return 0, when * it is expired ! */ - if ((timr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) + if (timr->it_sigev_notify != SIGEV_NONE) cur_setting->it_value.tv_nsec = 1; } else cur_setting->it_value = ktime_to_timespec(remaining); @@ -865,7 +869,7 @@ common_timer_set(struct k_itimer *timr, timr->it.real.interval = timespec_to_ktime(new_setting->it_interval); /* SIGEV_NONE timers are not queued ! See common_timer_get */ - if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) { + if (timr->it_sigev_notify == SIGEV_NONE) { /* Setup correct expiry time for relative timers */ if (mode == HRTIMER_MODE_REL) { hrtimer_add_expires(timer, timer->base->get_time());