Bugzilla: 1112073 Upstream-status: Sent for 3.16 and CC'd to stable Delivered-To: jwboyer@gmail.com Received: by 10.76.6.212 with SMTP id d20csp139586oaa; Mon, 23 Jun 2014 14:28:15 -0700 (PDT) X-Received: by 10.68.222.196 with SMTP id qo4mr32453892pbc.14.1403558895116; Mon, 23 Jun 2014 14:28:15 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id bm3si23587434pad.232.2014.06.23.14.27.47 for ; Mon, 23 Jun 2014 14:28:15 -0700 (PDT) Received-SPF: none (google.com: stable-owner@vger.kernel.org does not designate permitted sender hosts) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=neutral (google.com: stable-owner@vger.kernel.org does not designate permitted sender hosts) smtp.mail=stable-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752475AbaFWVWX (ORCPT + 73 others); Mon, 23 Jun 2014 17:22:23 -0400 Received: from mail-pb0-f42.google.com ([209.85.160.42]:39692 "EHLO mail-pb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752518AbaFWVWW (ORCPT ); Mon, 23 Jun 2014 17:22:22 -0400 Received: by mail-pb0-f42.google.com with SMTP id ma3so6319797pbc.15 for ; Mon, 23 Jun 2014 14:22:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-type:content-transfer-encoding; bh=7AW5eK5e3OhAcFYPrsffKoD56CbJdqfg9BcyF1JKfUE=; b=iLlWTJCuH9FlKTif4N6XtFZNvj8a/fbsjuP4kWWD/gmHHGEOWI6bh2Jm8X3vcN6GtV f7rqFO0SAMf197e66uME3pq8NzYFad4eRgJpBGON93P22+cPbqrsT9FZjMZqn2bJkEw4 EDZZy2MFqm3Kx2m/5g76NLDV1tgafEnwbgL1vg6IxlbPi6J8inkXwKP3FdMoTcfRBO6p dIcI1cV7VDNf6zKaMj+XS/ZiSxqpArhwvZ6xnXRmLfgD+x/JsxEcg2pX03BXHTKO9QNm nixe+cuug0X0E5idHuiLJzV0Wf6IhYsvVz/FvjY16pggduecA2NgNU2e7txqb+IcTBZ/ jBbA== X-Gm-Message-State: ALoCoQlblcwmTrVjpekrIOzidDrxwB18p5Rfd5SObiPQifpOQZmSFUKrxzV0kxCjcW/wVwxOzAG7 X-Received: by 10.68.197.8 with SMTP id iq8mr32930210pbc.124.1403558541680; Mon, 23 Jun 2014 14:22:21 -0700 (PDT) Received: from localhost (50-76-60-73-ip-static.hfc.comcastbusiness.net. [50.76.60.73]) by mx.google.com with ESMTPSA id fl6sm99195659pab.43.2014.06.23.14.22.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Jun 2014 14:22:20 -0700 (PDT) From: Andy Lutomirski Cc: "H. Peter Anvin" , Richard Weinberger , X86 ML , Eric Paris , Linux Kernel , security@kernel.org, Steven Rostedt , Borislav Petkov , =?UTF-8?q?Toralf=20F=C3=B6rster?= , Andy Lutomirski , stable@vger.kernel.org, Roland McGrath Subject: [PATCH] x86_32,entry: Do syscall exit work on badsys (CVE-2014-4508) Date: Mon, 23 Jun 2014 14:22:15 -0700 Message-Id: X-Mailer: git-send-email 1.9.3 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The bad syscall nr paths are their own incomprehensible route through the entry control flow. Rearrange them to work just like syscalls that return -ENOSYS. This fixes an OOPS in the audit code when fast-path auditing is enabled and sysenter gets a bad syscall nr (CVE-2014-4508). This has probably been broken since Linux 2.6.27: af0575bba0 i386 syscall audit fast-path Cc: stable@vger.kernel.org Cc: Roland McGrath Reported-by: Toralf Förster Signed-off-by: Andy Lutomirski --- I realize that the syscall audit fast path and badsys code, on 32-bit x86 no less, is possibly one of the least fun things in the kernel to review, but this is still a real security bug and should get fixed :( So I'm cc-ing a bunch of people and maybe someone will review it. arch/x86/kernel/entry_32.S | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index a2a4f46..f4258a5 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -431,9 +431,10 @@ sysenter_past_esp: jnz sysenter_audit sysenter_do_call: cmpl $(NR_syscalls), %eax - jae syscall_badsys + jae sysenter_badsys call *sys_call_table(,%eax,4) movl %eax,PT_EAX(%esp) +sysenter_after_call: LOCKDEP_SYS_EXIT DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF @@ -688,7 +689,12 @@ END(syscall_fault) syscall_badsys: movl $-ENOSYS,PT_EAX(%esp) - jmp resume_userspace + jmp syscall_exit +END(syscall_badsys) + +sysenter_badsys: + movl $-ENOSYS,PT_EAX(%esp) + jmp sysenter_after_call END(syscall_badsys) CFI_ENDPROC /* -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html