The patch titled
Subject: arm64: move ELF_ET_DYN_BASE to 4GB / 4MB
has been added to the -mm tree. Its filename is
arm64-move-elf_et_dyn_base-to-4gb-4mb.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-move-elf_et_dyn_base-to-4gb-4mb.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-move-elf_et_dyn_base-to-4gb-4mb.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: arm64: move ELF_ET_DYN_BASE to 4GB / 4MB
Now that explicitly executed loaders are loaded in the mmap region, we
have more freedom to decide where we position PIE binaries 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. On 32-bit use 4MB, to match ARM. This
could be 0x8000, the standard ET_EXEC load address, but that is needlessly
close to the NULL address, and anyone running arm compat PIE will have an
MMU, so the tight mapping is not needed.
Link: http://lkml.kernel.org/r/1498251600-132458-4-git-send-email-keescook@xxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/elf.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff -puN arch/arm64/include/asm/elf.h~arm64-move-elf_et_dyn_base-to-4gb-4mb arch/arm64/include/asm/elf.h
--- a/arch/arm64/include/asm/elf.h~arm64-move-elf_et_dyn_base-to-4gb-4mb
+++ a/arch/arm64/include/asm/elf.h
@@ -113,12 +113,11 @@
#define ELF_EXEC_PAGESIZE PAGE_SIZE
/*
- * 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.
+ * 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 (2 * TASK_SIZE_64 / 3)
+#define ELF_ET_DYN_BASE 0x100000000UL
#ifndef __ASSEMBLY__
@@ -173,7 +172,8 @@ extern int arch_setup_additional_pages(s
#ifdef CONFIG_COMPAT
-#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3)
+/* PIE load location for compat arm. Must match ARM ELF_ET_DYN_BASE. */
+#define COMPAT_ELF_ET_DYN_BASE 0x000400000UL
/* AArch32 registers. */
#define COMPAT_ELF_NGREG 18
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
exec-account-for-argv-envp-pointers.patch
mm-allow-slab_nomerge-to-be-set-at-build-time.patch
binfmt_elf-use-elf_et_dyn_base-only-for-pie.patch
arm-reduce-elf_et_dyn_base.patch
arm64-move-elf_et_dyn_base-to-4gb-4mb.patch
powerpc-reduce-elf_et_dyn_base.patch
s390-reduce-elf_et_dyn_base.patch
binfmt_elf-safely-increment-argv-pointers.patch
ipc-drop-non-rcu-allocation.patch
ipc-sem-do-not-use-ipc_rcu_free.patch
ipc-shm-do-not-use-ipc_rcu_free.patch
ipc-msg-do-not-use-ipc_rcu_free.patch
ipc-util-drop-ipc_rcu_free.patch
ipc-sem-avoid-ipc_rcu_alloc.patch
ipc-shm-avoid-ipc_rcu_alloc.patch
ipc-msg-avoid-ipc_rcu_alloc.patch
ipc-util-drop-ipc_rcu_alloc.patch
ipc-move-atomic_set-to-where-it-is-needed.patch
ipc-shm-remove-special-shm_alloc-free.patch
ipc-msg-remove-special-msg_alloc-free.patch
ipc-sem-drop-__sem_free.patch
efi-avoid-fortify-checks-in-efi-stub.patch
kexec_file-adjust-declaration-of-kexec_purgatory.patch
ib-rxe-do-not-copy-extra-stack-memory-to-skb.patch