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 474904a8e540e040e318f14a60fea3bf1f387e77..e1068987bad1c6fef286d084ca245cafbe0a8934 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -497,6 +497,7 @@ config ARCH_HAS_ELF_RANDOMIZE
          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 afb9cafd378618fef0d39a7bcae64e9950afdb1c..c1ff8ab12914ce6f934b3a65149e594d50fe76a6 100644 (file)
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -125,10 +125,6 @@ int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs);
 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 f724db00b2352d6b1294e0c1bba98e0133ea84ed..faad6df49e5b00a49f2b82f06dc48b735662e55c 100644 (file)
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -156,10 +156,6 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
 #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 535f196ffe02da7ad769ab0b7053b4dd5253dd82..31d747d46a23c1ba76b97755f44d1f20203028f6 100644 (file)
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -410,10 +410,6 @@ struct linux_binprm;
 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 57d289acb80325a063539eb8aa2ab92a6edefab0..ee46ffef608ee1679033a77c8ff5353ba6bfb51c 100644 (file)
--- a/arch/powerpc/include/asm/elf.h
+++ b/arch/powerpc/include/asm/elf.h
@@ -128,10 +128,6 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
        (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 ff662155b2c4972eac7dfbe2b75a8a5e87709525..a5c4978462c1e25c1d3505bb2c82d8c400d56a39 100644 (file)
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -226,9 +226,6 @@ struct linux_binprm;
 #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 935588d95c82fa35b68e3638d9acfe0a2734b373..f161c189c27b580ef02d1a1c7c8795806445c825 100644 (file)
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -339,9 +339,6 @@ extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
                                              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 b20c05477e90b60552811f59a5c9cab7697e28a6..241ef68d28930a7faed26f18b67b296138e61d9e 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1050,15 +1050,13 @@ static int load_elf_binary(struct linux_binprm *bprm)
        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 7a4eda02d2b1f7dab3b662ce7cda6fc28b693b62..b5f0bda9472e0720d5d1abb9368cf2b5ae0f5478 100644 (file)
--- 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