mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE
The arch_randomize_brk() function is used on several architectures,
even those that don't support ET_DYN ASLR. To avoid bulky extern/#define
tricks, consolidate the support under CONFIG_ARCH_HAS_ELF_RANDOMIZE for
the architectures that support it, while still handling CONFIG_COMPAT_BRK.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Hector Marco-Gisbert <hecmargi@upv.es>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: "David A. Long" <dave.long@linaro.org>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Arun Chandran <achandran@mvista.com>
Cc: Yann Droneaud <ydroneaud@opteya.com>
Cc: Min-Hua Chen <orca.chen@gmail.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Vineeth Vijayan <vvijayan@mvista.com>
Cc: Jeff Bailey <jeffbailey@google.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Behan Webster <behanw@converseincode.com>
Cc: Ismael Ripoll <iripoll@upv.es>
Cc: Jan-Simon Mller <dl9pf@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/Kconfig b/arch/Kconfig
index 474904a..e106898 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -497,6 +497,7 @@
An architecture supports choosing randomized locations for
stack, mmap, brk, and ET_DYN. Defined functions:
- arch_mmap_rnd()
+ - arch_randomize_brk()
#
# ABI hall of shame
diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index afb9caf..c1ff8ab 100644
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -125,10 +125,6 @@
extern void elf_set_personality(const struct elf32_hdr *);
#define SET_PERSONALITY(ex) elf_set_personality(&(ex))
-struct mm_struct;
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
#ifdef CONFIG_MMU
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
struct linux_binprm;
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index f724db0..faad6df 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -156,10 +156,6 @@
#define STACK_RND_MASK (0x3ffff >> (PAGE_SHIFT - 12))
#endif
-struct mm_struct;
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
#ifdef CONFIG_COMPAT
#ifdef __AARCH64EB__
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index 535f196..31d747d 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -410,10 +410,6 @@
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp);
-struct mm_struct;
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
struct arch_elf_state {
int fp_abi;
int interp_fp_abi;
diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h
index 57d289a..ee46ffe 100644
--- a/arch/powerpc/include/asm/elf.h
+++ b/arch/powerpc/include/asm/elf.h
@@ -128,10 +128,6 @@
(0x7ff >> (PAGE_SHIFT - 12)) : \
(0x3ffff >> (PAGE_SHIFT - 12)))
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
-
#ifdef CONFIG_SPU_BASE
/* Notes used in ET_CORE. Note name is "SPU/<fd>/<filename>". */
#define NT_SPU 1
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index ff66215..a5c4978 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -226,9 +226,6 @@
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
int arch_setup_additional_pages(struct linux_binprm *, int);
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
void *fill_cpu_elf_notes(void *ptr, struct save_area *sa, __vector128 *vxrs);
#endif
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 935588d9..f161c18 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -339,9 +339,6 @@
int uses_interp);
#define compat_arch_setup_additional_pages compat_arch_setup_additional_pages
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
-
/*
* True on X86_32 or when emulating IA32 on X86_64
*/
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index b20c054..241ef68 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1050,15 +1050,13 @@
current->mm->end_data = end_data;
current->mm->start_stack = bprm->p;
-#ifdef arch_randomize_brk
if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
current->mm->brk = current->mm->start_brk =
arch_randomize_brk(current->mm);
-#ifdef CONFIG_COMPAT_BRK
+#ifdef compat_brk_randomized
current->brk_randomized = 1;
#endif
}
-#endif
if (current->personality & MMAP_PAGE_ZERO) {
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
diff --git a/include/linux/elf-randomize.h b/include/linux/elf-randomize.h
index 7a4eda0..b5f0bda 100644
--- a/include/linux/elf-randomize.h
+++ b/include/linux/elf-randomize.h
@@ -1,10 +1,22 @@
#ifndef _ELF_RANDOMIZE_H
#define _ELF_RANDOMIZE_H
+struct mm_struct;
+
#ifndef CONFIG_ARCH_HAS_ELF_RANDOMIZE
static inline unsigned long arch_mmap_rnd(void) { return 0; }
+# if defined(arch_randomize_brk) && defined(CONFIG_COMPAT_BRK)
+# define compat_brk_randomized
+# endif
+# ifndef arch_randomize_brk
+# define arch_randomize_brk(mm) (mm->brk)
+# endif
#else
extern unsigned long arch_mmap_rnd(void);
+extern unsigned long arch_randomize_brk(struct mm_struct *mm);
+# ifdef CONFIG_COMPAT_BRK
+# define compat_brk_randomized
+# endif
#endif
#endif
