From: Kees Cook <keescook@chromium.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
David Brown <david.brown@linaro.org>,
Andy Lutomirski <luto@amacapital.net>,
"H. Peter Anvin" <hpa@zytor.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Mathias Krause <minipli@googlemail.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Arnd Bergmann <arnd@arndb.de>,
PaX Team <pageexec@freemail.hu>, Emese Revfy <re.emese@gmail.com>,
kernel-hardening@lists.openwall.com,
linux-kernel@vger.kernel.org,
linux-arch <linux-arch@vger.kernel.org>
Subject: [kernel-hardening] [PATCH v5 0/7] introduce post-init read-only memory
Date: Wed, 17 Feb 2016 14:41:11 -0800 [thread overview]
Message-ID: <1455748879-21872-1-git-send-email-keescook@chromium.org> (raw)
One of the easiest ways to protect the kernel from attack is to reduce
the internal attack surface exposed when a "write" flaw is available. By
making as much of the kernel read-only as possible, we reduce the
attack surface.
Many things are written to only during __init, and never changed
again. These cannot be made "const" since the compiler will do the wrong
thing (we do actually need to write to them). Instead, move these items
into a memory region that will be made read-only during mark_rodata_ro()
which happens after all kernel __init code has finished.
This introduces __ro_after_init as a way to mark such memory, and uses it
on the x86 and arm vDSO to kill an extant kernel exploitation method. Also
adds a new kernel parameter to help debug future use and adds an lkdtm
test to check the results.
-Kees
v5:
- rebased on linux-next (strtobool in -next, x86 vdso merge fixup)
- added ARM vDSO patch, david.brown
v4:
- adjust documentation for strtobool, andy.shevchenko
v3:
- conslidated mark_rodata_ro()
- make CONFIG_DEBUG_RODATA always enabled on x86, mingo
- enhanced strtobool and potential callers to use "on"/"off"
- use strtobool for rodata= param, gregkh
v2:
- renamed __read_only to __ro_after_init
next reply other threads:[~2016-02-17 22:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 22:41 Kees Cook [this message]
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 1/7] asm-generic: consolidate mark_rodata_ro() Kees Cook
2016-02-19 14:38 ` [kernel-hardening] " Will Deacon
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 2/7] init: create cmdline param to disable readonly Kees Cook
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 3/7] x86: make CONFIG_DEBUG_RODATA non-optional Kees Cook
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 4/7] introduce post-init read-only memory Kees Cook
2016-03-07 13:00 ` [kernel-hardening] " Christian Borntraeger
2016-03-08 0:16 ` Kees Cook
2016-03-08 0:23 ` Andy Lutomirski
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 5/7] lkdtm: verify that __ro_after_init works correctly Kees Cook
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 6/7] x86, vdso: mark vDSO read-only after init Kees Cook
2016-02-17 22:41 ` [kernel-hardening] [PATCH v5 7/7] ARM: vdso: Mark vDSO code as read-only Kees Cook
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