Kees Cook 7ece66e296 arch: Introduce post-init read-only memory ... commit c74ba8b348 upstream. 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 adds some documentation about the existing __read_mostly marking. This improves the security of the Linux kernel by marking formerly read-write memory regions as read-only on a fully booted up system. Based on work by PaX Team and Brad Spengler. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brad Spengler <spender@grsecurity.net> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Brown <david.brown@linaro.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Emese Revfy <re.emese@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathias Krause <minipli@googlemail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: PaX Team <pageexec@freemail.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-hardening@lists.openwall.com Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/1455748879-21872-5-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: David Brown <david.brown@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org>		2016-03-17 18:51:51 +00:00
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acpi	Merge branch 'acpi-pci'	2015-11-07 01:30:10 +01:00
asm-generic	arch: Introduce post-init read-only memory	2016-03-17 18:51:51 +00:00
clocksource
crypto	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2015-11-05 15:32:38 -08:00
drm	drm/nouveau: Fix pre-nv50 pageflip events (v4)	2015-12-04 13:49:38 +10:00
dt-bindings	ARM: DT updates for v4.4	2015-11-10 15:06:26 -08:00
keys
kvm	KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active	2015-11-24 18:07:40 +01:00
linux	arch: Introduce post-init read-only memory	2016-03-17 18:51:51 +00:00
math-emu
media
memory
misc
net	net: Propagate lookup failure in l3mdev_get_saddr to caller	2016-01-04 22:58:30 -05:00
pcmcia
ras
rdma	IB/mad: Require CM send method for everything except ClassPortInfo	2015-12-08 12:19:11 -05:00
rxrpc
scsi	Merge branch 'mkp-fixes' into fixes	2015-12-03 09:32:33 -08:00
soc	ARM: SoC driver updates for v4.4	2015-11-10 15:00:03 -08:00
sound	Merge remote-tracking branch 'asoc/fix/dapm' into asoc-linus	2016-01-05 23:07:32 +00:00
target	target: Fix race for SCF_COMPARE_AND_WRITE_POST checking	2015-11-28 19:33:15 -08:00
trace	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux	2015-11-11 09:03:01 -08:00
uapi	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2015-12-17 14:05:22 -08:00
video	gpu: ipu-v3: drop unused dmfc field from client platform data	2015-11-24 11:30:15 +01:00
xen	xen: Add RING_COPY_REQUEST()	2015-12-18 10:00:17 -05:00
Kbuild