From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
James Hogan <james.hogan@imgtec.com>,
Pratyush Anand <panand@redhat.com>,
Ingo Molnar <mingo@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
kernel-hardening@lists.openwall.com
Subject: [PATCH 4/4] s390: Reduce ELF_ET_DYN_BASE
Date: Thu, 22 Jun 2017 11:06:32 -0700 [thread overview]
Message-ID: <1498154792-49952-5-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1498154792-49952-1-git-send-email-keescook@chromium.org>
Now that explicitly executed loaders are loaded in the mmap region,
position PIE binaries lower in the address space to avoid possible
collisions with mmap or stack regions. For 64-bit, align to 4GB to
allow runtimes to use the entire 32-bit address space for 32-bit
pointers.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/s390/include/asm/elf.h | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index e8f623041769..7c58d599f91b 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -161,14 +161,13 @@ extern unsigned int vdso_enabled;
#define CORE_DUMP_USE_REGSET
#define ELF_EXEC_PAGESIZE 4096
-/* This is the location that an ET_DYN program is loaded if exec'ed. Typical
- use of this is to invoke "./ld.so someprog" to test out a new version of
- the loader. We need to make sure that it is out of the way of the program
- that it will "exec", and that there is sufficient room for the brk. 64-bit
- tasks are aligned to 4GB. */
-#define ELF_ET_DYN_BASE (is_compat_task() ? \
- (STACK_TOP / 3 * 2) : \
- (STACK_TOP / 3 * 2) & ~((1UL << 32) - 1))
+/*
+ * This is the base location for PIE (ET_DYN with INTERP) loads. On
+ * 64-bit, this is raised to 4GB to leave the entire 32-bit address
+ * space open for things that want to use the area for 32-bit pointers.
+ */
+#define ELF_ET_DYN_BASE (is_compat_task() ? 0x000400000UL : \
+ 0x100000000UL)
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. */
--
2.7.4
prev parent reply other threads:[~2017-06-22 18:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-22 18:06 [PATCH 0/4] Reduce ELF_ET_DYN_BASE Kees Cook
2017-06-22 18:06 ` [PATCH 1/4] arm: " Kees Cook
2017-06-22 18:06 ` [PATCH 2/4] arm64: " Kees Cook
2017-06-23 6:57 ` [kernel-hardening] " Ard Biesheuvel
2017-06-23 13:52 ` Kees Cook
2017-06-23 14:02 ` Kees Cook
2017-06-23 15:04 ` Ard Biesheuvel
2017-06-22 18:06 ` [PATCH 3/4] powerpc: " Kees Cook
2017-06-23 7:01 ` Michael Ellerman
2017-06-23 20:08 ` Kees Cook
2017-06-26 13:04 ` Michael Ellerman
2017-06-26 18:26 ` Kees Cook
2017-06-22 18:06 ` Kees Cook [this message]
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