linux-kernel - [34-longterm 096/209] ARM: 6489/1: thumb2: fix incorrect optimisation in usracc

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: <1302803039-9400-97-git-send-email-paul.gortmaker@windriver.com>
Date:	Thu, 14 Apr 2011 13:42:06 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	stable@...nel.org, linux-kernel@...r.kernel.org
Cc:	stable-review@...nel.org, Will Deacon <will.deacon@....com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [34-longterm 096/209] ARM: 6489/1: thumb2: fix incorrect optimisation in usracc

From: Will Deacon <will.deacon@....com>

  =====================================================================
  | This is a commit scheduled for the next v2.6.34 longterm release. |
  | If you see a problem with using this for longterm, please comment.|
  =====================================================================

commit 1142b71d85894dcff1466dd6c871ea3c89e0352c upstream.

Commit 8b592783 added a Thumb-2 variant of usracc which, when it is
called with \rept=2, calls usraccoff once with an offset of 0 and
secondly with a hard-coded offset of 4 in order to avoid incrementing
the pointer again. If \inc != 4 then we will store the data to the wrong
offset from \ptr. Luckily, the only caller that passes \rept=2 to this
function is __clear_user so we haven't been actively corrupting user data.

This patch fixes usracc to pass \inc instead of #4 to usraccoff
when it is called a second time.

Reported-by: Tony Thompson <tony.thompson@....com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 arch/arm/include/asm/assembler.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 6e8f05c..d757555 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -215,7 +215,7 @@
 	@ Slightly optimised to avoid incrementing the pointer twice
 	usraccoff \instr, \reg, \ptr, \inc, 0, \cond, \abort
 	.if	\rept == 2
-	usraccoff \instr, \reg, \ptr, \inc, 4, \cond, \abort
+	usraccoff \instr, \reg, \ptr, \inc, \inc, \cond, \abort
 	.endif

 	add\cond \ptr, #\rept * \inc
-- 
1.7.4.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/