[PATCH v3] security/Kconfig: further restrict HARDENED_USERCOPY

From	Tycho Andersen <tycho@docker.com>
Newsgroups	linux.kernel
Subject	[PATCH v3] security/Kconfig: further restrict HARDENED_USERCOPY
Date	2017-03-09 22:30 +0100
Message-ID	<tjdNf-2mg-3@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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It doesn't make sense to have HARDENED_USERCOPY when either /dev/kmem is
enabled or /dev/mem can be used to read kernel memory (i.e.
!STRICT_DEVMEM).

v2: add !MMU depend as well
v3: drop !MMU, s/ARCH_HAS_DEVMEM_IS_ALLOWED/DEVMEM, which makes the above
    commit message actually match the logic again

Signed-off-by: Tycho Andersen <tycho@docker.com>
CC: Kees Cook <keescook@chromium.org>
CC: "Serge E. Hallyn" <serge@hallyn.com>
CC: James Morris <james.l.morris@oracle.com>
---
 security/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/Kconfig b/security/Kconfig
index 3ff1bf9..4619cee 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -142,6 +142,8 @@ config HARDENED_USERCOPY
 	bool "Harden memory copies between kernel and userspace"
 	depends on HAVE_ARCH_HARDENED_USERCOPY
 	depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
+	depends on !DEVKMEM
+	depends on !DEVMEM || STRICT_DEVMEM
 	select BUG
 	help
 	  This option checks for obviously wrong memory regions when
-- 
2.7.4

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[PATCH v3] security/Kconfig: further restrict HARDENED_USERCOPY Tycho Andersen <tycho@docker.com> - 2017-03-09 22:30 +0100
  Re: [PATCH v3] security/Kconfig: further restrict HARDENED_USERCOPY Kees Cook <keescook@chromium.org> - 2017-03-09 22:40 +0100

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