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From: Michael Ellerman <mpe@ellerman.id.au>
To: linuxppc-dev@ozlabs.org
Cc: oohall@gmail.com, joel@jms.id.au, dja@axtens.net
Subject: [PATCH v2 09/10] powerpc/configs/skiroot: Enable some more hardening options
Date: Tue, 21 Jan 2020 15:29:59 +1100	[thread overview]
Message-ID: <20200121043000.16212-9-mpe@ellerman.id.au> (raw)
In-Reply-To: <20200121043000.16212-1-mpe@ellerman.id.au>

Enable more hardening options.

Note BUG_ON_DATA_CORRUPTION selects DEBUG_LIST and is essentially just
a synonym for it.

DEBUG_SG, DEBUG_NOTIFIERS, DEBUG_LIST, DEBUG_CREDENTIALS and
SCHED_STACK_END_CHECK should all be low overhead and just add a few
extra checks.

SLAB_FREELIST_RANDOM, and SLUB_DEBUG_ON will add some overhead to the
SLAB allocator, but nothing that should be meaningful for skiroot.

Unselecting SLAB_MERGE_DEFAULT causes the SLAB to use more memory, but
the skiroot kernel shouldn't be memory constrained on any of our
systems, all it does is run a small bootloader.

Disabling merging has some security/robustness benefit as it means a
user-after-free or overflow will be limited to the objects in that
slab, rather than potentially affecting objects from unrelated slabs
that have been merged.

Note also that slab merging is disabled anyway by enabling
SLUB_DEBUG_ON, because of the SLAB_NEVER_MERGE mask.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/configs/skiroot_defconfig | 8 ++++++++
 1 file changed, 8 insertions(+)

v2: Add more explanation about slab merging.

diff --git a/arch/powerpc/configs/skiroot_defconfig b/arch/powerpc/configs/skiroot_defconfig
index 28cfd68e8b16..ca6f1842aa29 100644
--- a/arch/powerpc/configs/skiroot_defconfig
+++ b/arch/powerpc/configs/skiroot_defconfig
@@ -23,6 +23,8 @@ CONFIG_EXPERT=y
 # CONFIG_AIO is not set
 CONFIG_PERF_EVENTS=y
 # CONFIG_COMPAT_BRK is not set
+# CONFIG_SLAB_MERGE_DEFAULT is not set
+CONFIG_SLAB_FREELIST_RANDOM=y
 CONFIG_SLAB_FREELIST_HARDENED=y
 CONFIG_PPC64=y
 CONFIG_ALTIVEC=y
@@ -293,6 +295,8 @@ CONFIG_LIBCRC32C=y
 # CONFIG_XZ_DEC_SPARC is not set
 CONFIG_PRINTK_TIME=y
 CONFIG_MAGIC_SYSRQ=y
+CONFIG_SLUB_DEBUG_ON=y
+CONFIG_SCHED_STACK_END_CHECK=y
 CONFIG_DEBUG_STACKOVERFLOW=y
 CONFIG_PANIC_ON_OOPS=y
 CONFIG_SOFTLOCKUP_DETECTOR=y
@@ -301,6 +305,10 @@ CONFIG_HARDLOCKUP_DETECTOR=y
 CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
 CONFIG_WQ_WATCHDOG=y
 # CONFIG_SCHED_DEBUG is not set
+CONFIG_DEBUG_SG=y
+CONFIG_DEBUG_NOTIFIERS=y
+CONFIG_BUG_ON_DATA_CORRUPTION=y
+CONFIG_DEBUG_CREDENTIALS=y
 # CONFIG_FTRACE is not set
 CONFIG_XMON=y
 # CONFIG_RUNTIME_TESTING_MENU is not set
-- 
2.21.1


  parent reply	other threads:[~2020-01-21  4:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21  4:29 [PATCH v2 01/10] powerpc/configs: Drop CONFIG_QLGE which moved to staging Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 02/10] powerpc/configs: NET_CADENCE became NET_VENDOR_CADENCE Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 03/10] powerpc/configs: Drop NET_VENDOR_HP which moved to staging Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 04/10] powerpc/configs/skiroot: Drop HID_LOGITECH Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 05/10] powerpc/configs/skiroot: Drop default n CONFIG_CRYPTO_ECHAINIV Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 06/10] powerpc/configs/skiroot: Update for symbol movement only Michael Ellerman
2020-01-21  4:29 ` [PATCH v2 07/10] powerpc/configs/skiroot: Enable security features Michael Ellerman
2020-01-23 13:38   ` Joel Stanley
2020-01-29  1:29     ` Daniel Axtens
2020-01-21  4:29 ` [PATCH v2 08/10] powerpc/configs/skiroot: Disable xmon default & enable reboot on panic Michael Ellerman
2020-01-21  4:29 ` Michael Ellerman [this message]
2020-01-21  4:30 ` [PATCH v2 10/10] powerpc/configs/skiroot: Enable CONFIG_PRINTK_CALLER Michael Ellerman
2020-02-04 12:01 ` [PATCH v2 01/10] powerpc/configs: Drop CONFIG_QLGE which moved to staging Michael Ellerman

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