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>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190724191749.824479528@linuxfoundation.org>
Date:   Wed, 24 Jul 2019 21:21:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Rolf Eike Beer <eike-kernel@...tec.de>,
        Helge Deller <deller@....de>
Subject: [PATCH 5.1 347/371] parisc: Ensure userspace privilege for ptraced processes in regset functions

From: Helge Deller <deller@....de>

commit 34c32fc603311a72cb558e5e337555434f64c27b upstream.

On parisc the privilege level of a process is stored in the lowest two bits of
the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0
for the kernel and privilege level 3 for user-space. So userspace should not be
allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege
level to e.g. 0 to try to gain kernel privileges.

This patch prevents such modifications in the regset support functions by
always setting the two lowest bits to one (which relates to privilege level 3
for user-space) if IAOQ0 or IAOQ1 are modified via ptrace regset calls.

Link: https://bugs.gentoo.org/481768
Cc: <stable@...r.kernel.org> # v4.7+
Tested-by: Rolf Eike Beer <eike-kernel@...tec.de>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/parisc/kernel/ptrace.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -496,7 +496,8 @@ static void set_reg(struct pt_regs *regs
 			return;
 	case RI(iaoq[0]):
 	case RI(iaoq[1]):
-			regs->iaoq[num - RI(iaoq[0])] = val;
+			/* set 2 lowest bits to ensure userspace privilege: */
+			regs->iaoq[num - RI(iaoq[0])] = val | 3;
 			return;
 	case RI(sar):	regs->sar = val;
 			return;


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ