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From: riel@redhat.com
To: linux-kernel@vger.kernel.org
Cc: danielmicay@gmail.com, tytso@mit.edu, keescook@chromium.org,
	hpa@zytor.com, luto@amacapital.net, mingo@kernel.org,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	catalin.marinas@arm.com, linux-sh@vger.kernel.org,
	ysato@users.sourceforge.jp, kernel-hardening@lists.openwall.com
Subject: [kernel-hardening] [PATCH v2 0/5] stackprotector: ascii armor the stack canary
Date: Wed, 24 May 2017 11:57:46 -0400	[thread overview]
Message-ID: <20170524155751.424-1-riel@redhat.com> (raw)

Zero out the first byte of the stack canary value on 64 bit systems,
in order to mitigate unterminated C string overflows.

The null byte both prevents C string functions from reading the
canary, and from writing it if the canary value were guessed or
obtained through some other means.
    
Reducing the entropy by 8 bits is acceptable on 64-bit systems,
which will still have 56 bits of entropy left, but not on 32
bit systems, so the "ascii armor" canary is only implemented on
64-bit systems.

Inspired by the "ascii armor" code in execshield and Daniel Micay's
linux-hardened tree.

Also see https://github.com/thestinger/linux-hardened/

v2:
 - improve changelogs
 - address Ingo's coding style comments

WARNING: multiple messages have this Message-ID (diff)
From: riel@redhat.com
To: linux-kernel@vger.kernel.org
Cc: danielmicay@gmail.com, tytso@mit.edu, keescook@chromium.org,
	hpa@zytor.com, luto@amacapital.net, mingo@kernel.org,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	catalin.marinas@arm.com, linux-sh@vger.kernel.org,
	ysato@users.sourceforge.jp, kernel-hardening@lists.openwall.com
Subject: [PATCH v2 0/5] stackprotector: ascii armor the stack canary
Date: Wed, 24 May 2017 15:57:46 +0000	[thread overview]
Message-ID: <20170524155751.424-1-riel@redhat.com> (raw)

Zero out the first byte of the stack canary value on 64 bit systems,
in order to mitigate unterminated C string overflows.

The null byte both prevents C string functions from reading the
canary, and from writing it if the canary value were guessed or
obtained through some other means.
    
Reducing the entropy by 8 bits is acceptable on 64-bit systems,
which will still have 56 bits of entropy left, but not on 32
bit systems, so the "ascii armor" canary is only implemented on
64-bit systems.

Inspired by the "ascii armor" code in execshield and Daniel Micay's
linux-hardened tree.

Also see https://github.com/thestinger/linux-hardened/

v2:
 - improve changelogs
 - address Ingo's coding style comments


WARNING: multiple messages have this Message-ID (diff)
From: riel@redhat.com (riel at redhat.com)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 0/5] stackprotector: ascii armor the stack canary
Date: Wed, 24 May 2017 11:57:46 -0400	[thread overview]
Message-ID: <20170524155751.424-1-riel@redhat.com> (raw)

Zero out the first byte of the stack canary value on 64 bit systems,
in order to mitigate unterminated C string overflows.

The null byte both prevents C string functions from reading the
canary, and from writing it if the canary value were guessed or
obtained through some other means.
    
Reducing the entropy by 8 bits is acceptable on 64-bit systems,
which will still have 56 bits of entropy left, but not on 32
bit systems, so the "ascii armor" canary is only implemented on
64-bit systems.

Inspired by the "ascii armor" code in execshield and Daniel Micay's
linux-hardened tree.

Also see https://github.com/thestinger/linux-hardened/

v2:
 - improve changelogs
 - address Ingo's coding style comments

WARNING: multiple messages have this Message-ID (diff)
From: riel@redhat.com
To: linux-kernel@vger.kernel.org
Cc: danielmicay@gmail.com, tytso@mit.edu, keescook@chromium.org,
	hpa@zytor.com, luto@amacapital.net, mingo@kernel.org,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	catalin.marinas@arm.com, linux-sh@vger.kernel.org,
	ysato@users.sourceforge.jp, kernel-hardening@lists.openwall.com
Subject: [PATCH v2 0/5] stackprotector: ascii armor the stack canary
Date: Wed, 24 May 2017 11:57:46 -0400	[thread overview]
Message-ID: <20170524155751.424-1-riel@redhat.com> (raw)

Zero out the first byte of the stack canary value on 64 bit systems,
in order to mitigate unterminated C string overflows.

The null byte both prevents C string functions from reading the
canary, and from writing it if the canary value were guessed or
obtained through some other means.
    
Reducing the entropy by 8 bits is acceptable on 64-bit systems,
which will still have 56 bits of entropy left, but not on 32
bit systems, so the "ascii armor" canary is only implemented on
64-bit systems.

Inspired by the "ascii armor" code in execshield and Daniel Micay's
linux-hardened tree.

Also see https://github.com/thestinger/linux-hardened/

v2:
 - improve changelogs
 - address Ingo's coding style comments

             reply	other threads:[~2017-05-24 15:57 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-24 15:57 riel [this message]
2017-05-24 15:57 ` [PATCH v2 0/5] stackprotector: ascii armor the stack canary riel
2017-05-24 15:57 ` riel at redhat.com
2017-05-24 15:57 ` riel
2017-05-24 15:57 ` [kernel-hardening] [PATCH 1/5] random,stackprotect: introduce get_random_canary function riel
2017-05-24 15:57   ` riel
2017-05-24 15:57   ` [PATCH 1/5] random, stackprotect: " riel at redhat.com
2017-05-24 15:57   ` [PATCH 1/5] random,stackprotect: " riel
2017-05-24 16:15   ` [kernel-hardening] " Kees Cook
2017-05-24 16:15     ` Kees Cook
2017-05-24 16:15     ` [PATCH 1/5] random, stackprotect: " Kees Cook
2017-05-24 16:15     ` [PATCH 1/5] random,stackprotect: " Kees Cook
2017-05-24 15:57 ` [kernel-hardening] [PATCH 2/5] fork,random: use get_random_canary to set tsk->stack_canary riel
2017-05-24 15:57   ` riel
2017-05-24 15:57   ` [PATCH 2/5] fork, random: " riel at redhat.com
2017-05-24 15:57   ` [PATCH 2/5] fork,random: " riel
2017-05-24 16:16   ` [kernel-hardening] " Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 16:16     ` [PATCH 2/5] fork, random: " Kees Cook
2017-05-24 16:16     ` [PATCH 2/5] fork,random: " Kees Cook
2017-05-24 15:57 ` [kernel-hardening] [PATCH 3/5] x86: ascii armor the x86_64 boot init stack canary riel
2017-05-24 15:57   ` riel
2017-05-24 15:57   ` riel at redhat.com
2017-05-24 15:57   ` riel
2017-05-24 16:16   ` [kernel-hardening] " Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 15:57 ` [kernel-hardening] [PATCH 4/5] arm64: ascii armor the arm64 " riel
2017-05-24 15:57   ` riel
2017-05-24 15:57   ` riel at redhat.com
2017-05-24 15:57   ` riel
2017-05-24 16:16   ` [kernel-hardening] " Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 16:16     ` Kees Cook
2017-05-24 15:57 ` [kernel-hardening] [PATCH 5/5] sh64: ascii armor the sh64 " riel
2017-05-24 15:57   ` riel
2017-05-24 15:57   ` riel at redhat.com
2017-05-24 15:57   ` riel
2017-05-24 16:34 ` [kernel-hardening] " Rik van Riel
2017-05-24 16:34   ` Rik van Riel
2017-05-24 16:34   ` Rik van Riel
2017-05-24 16:34   ` Rik van Riel
2017-05-24 16:35   ` [kernel-hardening] " Kees Cook
2017-05-24 16:35     ` Kees Cook
2017-05-24 16:35     ` Kees Cook
2017-05-24 16:35     ` Kees Cook
2017-09-19 17:16 ` [kernel-hardening] [PATCH v2 0/5] stackprotector: ascii armor the " Solar Designer
2017-09-19 17:16   ` Solar Designer
2017-09-19 17:16   ` Solar Designer
2017-09-19 20:22   ` Kees Cook
2017-09-19 20:22     ` Kees Cook
2017-09-19 20:22     ` Kees Cook
2017-09-19 21:10   ` Daniel Micay
2017-09-19 21:10     ` Daniel Micay
2017-09-19 21:10     ` Daniel Micay
2017-09-20 11:18   ` Yann Droneaud
2017-09-20 11:18     ` Yann Droneaud
2017-09-20 11:18     ` Yann Droneaud
2017-09-20 15:03     ` Solar Designer
2017-09-20 15:03       ` Solar Designer
2017-09-20 15:03       ` Solar Designer

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