From: Kees Cook <keescook@chromium.org> To: Borislav Petkov <bp@alien8.de> Cc: Kees Cook <keescook@chromium.org>, Hector Marco-Gisbert <hecmargi@upv.es>, Jason Gunthorpe <jgg@mellanox.com>, Catalin Marinas <catalin.marinas@arm.com>, Jason Gunthorpe <jgg@ziepe.ca>, Russell King <linux@armlinux.org.uk>, Will Deacon <will@kernel.org>, Jann Horn <jannh@google.com>, x86@kernel.org, linux-arm-kernel@lists.infradead.org, kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org Subject: [PATCH v4 6/6] arm64, elf: Disable automatic READ_IMPLIES_EXEC for 64-bit address spaces Date: Mon, 24 Feb 2020 21:13:07 -0800 Message-ID: <20200225051307.6401-7-keescook@chromium.org> (raw) In-Reply-To: <20200225051307.6401-1-keescook@chromium.org> With arm64 64-bit environments, there should never be a need for automatic READ_IMPLIES_EXEC, as the architecture has always been execute-bit aware (as in, the default memory protection should be NX unless a region explicitly requests to be executable). Suggested-by: Hector Marco-Gisbert <hecmargi@upv.es> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/include/asm/elf.h | 4 ++-- fs/compat_binfmt_elf.c | 5 +++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 03ada29984a7..ea9221ed68a1 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -105,7 +105,7 @@ * CPU*: | arm32 | arm64 | * ELF: | | | * -------------------------------|------------| - * missing GNU_STACK | exec-all | exec-all | + * missing GNU_STACK | exec-all | exec-none | * GNU_STACK == RWX | exec-stack | exec-stack | * GNU_STACK == RW | exec-none | exec-none | * @@ -117,7 +117,7 @@ * *all arm64 CPUs support NX, so there is no "lacks NX" column. * */ -#define elf_read_implies_exec(ex,stk) (stk == EXSTACK_DEFAULT) +#define compat_elf_read_implies_exec(ex, stk) (stk == EXSTACK_DEFAULT) #define CORE_DUMP_USE_REGSET #define ELF_EXEC_PAGESIZE PAGE_SIZE diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index aaad4ca1217e..3068d57436b3 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -113,6 +113,11 @@ #define arch_setup_additional_pages compat_arch_setup_additional_pages #endif +#ifdef compat_elf_read_implies_exec +#undef elf_read_implies_exec +#define elf_read_implies_exec compat_elf_read_implies_exec +#endif + /* * Rename a few of the symbols that binfmt_elf.c will define. * These are all local so the names don't really matter, but it -- 2.20.1
prev parent reply index Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-25 5:13 [PATCH v4 0/6] binfmt_elf: Update READ_IMPLIES_EXEC logic for modern CPUs Kees Cook 2020-02-25 5:13 ` [PATCH v4 1/6] x86/elf: Add table to document READ_IMPLIES_EXEC Kees Cook 2020-03-11 19:44 ` Borislav Petkov 2020-03-13 0:06 ` Kees Cook 2020-02-25 5:13 ` [PATCH v4 2/6] x86/elf: Split READ_IMPLIES_EXEC from executable GNU_STACK Kees Cook 2020-02-25 5:13 ` [PATCH v4 3/6] x86/elf: Disable automatic READ_IMPLIES_EXEC for 64-bit address spaces Kees Cook 2020-02-25 5:13 ` [PATCH v4 4/6] arm32/64, elf: Add tables to document READ_IMPLIES_EXEC Kees Cook 2020-02-25 5:13 ` [PATCH v4 5/6] arm32/64, elf: Split READ_IMPLIES_EXEC from executable GNU_STACK Kees Cook 2020-02-25 5:13 ` Kees Cook [this message]
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