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From: Russell Currey <ruscur@russell.cc>
To: linuxppc-dev@lists.ozlabs.org
Cc: Russell Currey <ruscur@russell.cc>,
	christophe.leroy@c-s.fr, joel@jms.id.au, mpe@ellerman.id.au,
	ajd@linux.ibm.com, dja@axtens.net, npiggin@gmail.com,
	kernel-hardening@lists.openwall.com
Subject: [PATCH v4 4/4] powerpc: Enable STRICT_MODULE_RWX
Date: Mon, 14 Oct 2019 16:13:20 +1100	[thread overview]
Message-ID: <20191014051320.158682-5-ruscur@russell.cc> (raw)
In-Reply-To: <20191014051320.158682-1-ruscur@russell.cc>

Whether STRICT_MODULE_RWX is enabled by default depends on powerpc
platform - in arch/Kconfig, STRICT_MODULE_RWX depends on
ARCH_OPTIONAL_KERNEL_RWX, which in arch/powerpc/Kconfig is selected if
ARCH_HAS_STRICT_KERNEL_RWX is selected, which is only true with
CONFIG_RELOCATABLE *disabled*.

defconfigs like skiroot_defconfig which turn STRICT_KERNEL_RWX on when
it is not already on by default also do NOT enable STRICT_MODULE_RWX
automatically, so it is explicitly enabled there in this patch.

Thus, on by default for ppc32 only.  Module RWX doesn't provide a whole
lot of value with Kernel RWX off, but it doesn't hurt, either.  The next
step is to make STRICT_KERNEL_RWX compatible with RELOCATABLE so it can
be on by default.

Tested-by: Daniel Axtens <dja@axtens.net> # e6500
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
 arch/powerpc/Kconfig                   | 1 +
 arch/powerpc/configs/skiroot_defconfig | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8f7005f0d097..212c4d02be40 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -135,6 +135,7 @@ config PPC
 	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX	if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION)
+	select ARCH_HAS_STRICT_MODULE_RWX
 	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UACCESS_FLUSHCACHE
 	select ARCH_HAS_UACCESS_MCSAFE		if PPC64
diff --git a/arch/powerpc/configs/skiroot_defconfig b/arch/powerpc/configs/skiroot_defconfig
index 1253482a67c0..719d899081b3 100644
--- a/arch/powerpc/configs/skiroot_defconfig
+++ b/arch/powerpc/configs/skiroot_defconfig
@@ -31,6 +31,7 @@ CONFIG_PERF_EVENTS=y
 CONFIG_SLAB_FREELIST_HARDENED=y
 CONFIG_JUMP_LABEL=y
 CONFIG_STRICT_KERNEL_RWX=y
+CONFIG_STRICT_MODULE_RWX=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_SIG=y
-- 
2.23.0


  parent reply	other threads:[~2019-10-14  5:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-14  5:13 [PATCH v4 0/4] Implement STRICT_MODULE_RWX for powerpc Russell Currey
2019-10-14  5:13 ` [PATCH v4 1/4] powerpc/mm: Implement set_memory() routines Russell Currey
2019-10-14  5:13 ` [PATCH v4 2/4] powerpc/kprobes: Mark newly allocated probes as RO Russell Currey
2019-10-14  5:13 ` [PATCH v4 3/4] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime Russell Currey
2019-10-14  5:13 ` Russell Currey [this message]
2019-10-29 23:02 ` [PATCH v4 0/4] Implement STRICT_MODULE_RWX for powerpc Kees Cook
2019-10-30  0:16   ` Michael Ellerman
2019-10-30 18:43     ` Kees Cook

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