Patch "s390/ptrace: fix PSW mask check" has been added to the 3.10-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    s390/ptrace: fix PSW mask check

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-ptrace-fix-psw-mask-check.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From dab6cf55f81a6e16b8147aed9a843e1691dcd318 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Date: Mon, 23 Jun 2014 15:29:40 +0200
Subject: s390/ptrace: fix PSW mask check

From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

commit dab6cf55f81a6e16b8147aed9a843e1691dcd318 upstream.

The PSW mask check of the PTRACE_POKEUSR_AREA command is incorrect.
The PSW_MASK_USER define contains the PSW_MASK_ASC bits, the ptrace
interface accepts all combinations for the address-space-control
bits. To protect the kernel space the PSW mask check in ptrace needs
to reject the address-space-control bit combination for home space.

Fixes CVE-2014-3534

Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
[bwh: Backported to 3.2:
 - The PSW user-settable bitmasks are constant, never including PSW_MASK_RI
 - The kernel can run in either home or primary space, so instead of
   checking that the ASC bits are not equal to PSW_ASC_HOME, we have to
   check that they don't match psw_kernel_bits
 - For the same reason, the required values of non-user-settable bits
   are variables (psw_user_bits/psw32_user_bits) and remain so]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/s390/kernel/ptrace.c |   23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -313,11 +313,18 @@ static int __poke_user(struct task_struc
 		/*
 		 * psw and gprs are stored on the stack
 		 */
-		if (addr == (addr_t) &dummy->regs.psw.mask &&
-		    ((data & ~PSW_MASK_USER) != psw_user_bits ||
-		     ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))))
-			/* Invalid psw mask. */
-			return -EINVAL;
+		if (addr == (addr_t) &dummy->regs.psw.mask) {
+			if ((data ^ psw_user_bits) & ~PSW_MASK_USER)
+				/* Invalid psw mask. */
+				return -EINVAL;
+			if ((data & PSW_MASK_ASC) ==
+			    (psw_kernel_bits & PSW_MASK_ASC))
+				/* Invalid address-space-control bits */
+				return -EINVAL;
+			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
+				/* Invalid addressing mode bits */
+				return -EINVAL;
+		}
 		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
 
 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
@@ -627,9 +634,13 @@ static int __poke_user_compat(struct tas
 		 */
 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
 			/* Build a 64 bit psw mask from 31 bit mask. */
-			if ((tmp & ~PSW32_MASK_USER) != psw32_user_bits)
+			if ((tmp ^ psw32_user_bits) & ~PSW32_MASK_USER)
 				/* Invalid psw mask. */
 				return -EINVAL;
+			if ((data & PSW32_MASK_ASC) ==
+			    ((psw_kernel_bits & PSW_MASK_ASC) >> 32))
+				/* Invalid address-space-control bits */
+				return -EINVAL;
 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 				(regs->psw.mask & PSW_MASK_BA) |
 				(__u64)(tmp & PSW32_MASK_USER) << 32;


Patches currently in stable-queue which might be from schwidefsky@xxxxxxxxxx are

queue-3.10/s390-ptrace-fix-psw-mask-check.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]