Message-ID: <Pine.LNX.4.64.0708311228020.4135@jikos.suse.cz>
Date:	Fri, 31 Aug 2007 13:56:03 +0200 (CEST)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Mike Frysinger <vapier.adi@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] i386 and x86_64: randomize brk()

On Thu, 30 Aug 2007, Andrew Morton wrote:

> Not strongly, but the general opinion seems to be that ARCH_HAS_FOO is 
> sucky.  It should at least be done in Kconfig rather than in .h, but 
> even better is just to implement the thing for all architectures.

Below is an updated patch. checkpatch complains about adding extern into 
arch/x86_64/ia32/ia32_binfmt.c, but it's needed to work with this crazy 

	#include "../../../fs/binfmt_elf.c"

in it.

It also complains about multiple assignments, but I don't seem to see 
anything wrong with them here.


From: Jiri Kosina <jkosina@...e.cz>

i386 and x86_64: randomize brk()

This patch randomizes the location of the heap (brk) for i386 and x86_64. 
The range is randomized in the range starting at current brk location up 
to 0x02000000 offset for both architectures. This, together with 
pie-executable-randomization.patch and 
pie-executable-randomization-fix.patch, should make the address space 
randomization on i386 and x86_64 complete.

The empty stubs are not added for architectures that don't support ELF 
binaries, namely blackfin, h8300, m68knommu and v850.

Signed-off-by: Jiri Kosina <jkosina@...e.cz>

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 8466471..ba8ad15 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -949,3 +949,17 @@ unsigned long arch_align_stack(unsigned long sp)
 		sp -= get_random_int() % 8192;
 	return sp & ~0xf;
 }
+
+void arch_randomize_brk(void)
+{
+	unsigned long new_brk;
+	unsigned long range_start;
+	unsigned long range_end;
+
+	range_start = current->mm->brk;
+	range_end = range_start + 0x02000000;
+	new_brk = randomize_range(range_start, range_end, 0);
+	if (new_brk)
+		current->mm->brk = current->mm->start_brk = new_brk;
+}
+
diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index dffd2ac..ccc4350 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -262,6 +262,7 @@ static void elf32_init(struct pt_regs *);
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
 #define arch_setup_additional_pages syscall32_setup_pages
 extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
+extern void arch_randomize_brk(void);
 
 #include "../../../fs/binfmt_elf.c" 
 
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 2842f50..fe7203b 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -902,3 +902,17 @@ unsigned long arch_align_stack(unsigned long sp)
 		sp -= get_random_int() % 8192;
 	return sp & ~0xf;
 }
+
+void arch_randomize_brk(void)
+{
+	unsigned long new_brk;
+	unsigned long range_start;
+	unsigned long range_end;
+
+	range_start = current->mm->brk;
+	range_end = range_start + 0x02000000;
+	new_brk = randomize_range(range_start, range_end, 0);
+	if (new_brk)
+		current->mm->brk = current->mm->start_brk = new_brk;
+}
+
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index d65f1d9..4c92461 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1073,6 +1073,9 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 	current->mm->end_data = end_data;
 	current->mm->start_stack = bprm->p;
 
+	if (current->flags & PF_RANDOMIZE)
+		arch_randomize_brk();
+
 	if (current->personality & MMAP_PAGE_ZERO) {
 		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
 		   and some applications "depend" upon this behavior.
diff --git a/include/asm-alpha/elf.h b/include/asm-alpha/elf.h
index 6c2d78f..18210cc 100644
--- a/include/asm-alpha/elf.h
+++ b/include/asm-alpha/elf.h
@@ -163,5 +163,9 @@ extern int alpha_l3_cacheshape;
     NEW_AUX_ENT(AT_L3_CACHESHAPE, alpha_l3_cacheshape);		\
   } while (0)
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* __KERNEL__ */
 #endif /* __ASM_ALPHA_ELF_H */
diff --git a/include/asm-arm/elf.h b/include/asm-arm/elf.h
index ec1c685..eeeee3f 100644
--- a/include/asm-arm/elf.h
+++ b/include/asm-arm/elf.h
@@ -116,4 +116,8 @@ extern char elf_platform[];
 
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-avr32/elf.h b/include/asm-avr32/elf.h
index d334b49..61b7d81 100644
--- a/include/asm-avr32/elf.h
+++ b/include/asm-avr32/elf.h
@@ -107,4 +107,8 @@ typedef struct user_fpu_struct elf_fpregset_t;
 #define SET_PERSONALITY(ex, ibcs2) set_personality(PER_LINUX_32BIT)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* __ASM_AVR32_ELF_H */
diff --git a/include/asm-cris/elf.h b/include/asm-cris/elf.h
index 96a40c1..10607c7 100644
--- a/include/asm-cris/elf.h
+++ b/include/asm-cris/elf.h
@@ -93,4 +93,8 @@ typedef unsigned long elf_fpregset_t;
 
 #endif /* __KERNEL__ */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-frv/elf.h b/include/asm-frv/elf.h
index 7df58a3..07df9dd 100644
--- a/include/asm-frv/elf.h
+++ b/include/asm-frv/elf.h
@@ -141,4 +141,8 @@ do {											\
 #define SET_PERSONALITY(ex, ibcs2) set_personality((ibcs2)?PER_SVR4:PER_LINUX)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index b32df3a..5935d4c 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -160,4 +160,6 @@ do if (vdso_enabled) {							\
 
 #endif
 
+extern void arch_randomize_brk(void);
+
 #endif
diff --git a/include/asm-ia64/elf.h b/include/asm-ia64/elf.h
index 25f9835..3b84b0d 100644
--- a/include/asm-ia64/elf.h
+++ b/include/asm-ia64/elf.h
@@ -249,4 +249,8 @@ do {									\
 
 #endif /* __KERNEL__ */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* _ASM_IA64_ELF_H */
diff --git a/include/asm-m32r/elf.h b/include/asm-m32r/elf.h
index bbee8b2..33a5244 100644
--- a/include/asm-m32r/elf.h
+++ b/include/asm-m32r/elf.h
@@ -133,4 +133,8 @@ typedef elf_fpreg_t elf_fpregset_t;
 #define SET_PERSONALITY(ex, ibcs2) set_personality(PER_LINUX)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif  /* _ASM_M32R__ELF_H */
diff --git a/include/asm-m68k/elf.h b/include/asm-m68k/elf.h
index eb63b85..f6ff4fe 100644
--- a/include/asm-m68k/elf.h
+++ b/include/asm-m68k/elf.h
@@ -118,4 +118,8 @@ typedef struct user_m68kfp_struct elf_fpregset_t;
 #define SET_PERSONALITY(ex, ibcs2) set_personality((ibcs2)?PER_SVR4:PER_LINUX)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-mips/elf.h b/include/asm-mips/elf.h
index e7d95d4..571cd80 100644
--- a/include/asm-mips/elf.h
+++ b/include/asm-mips/elf.h
@@ -372,4 +372,8 @@ extern int dump_task_fpu(struct task_struct *, elf_fpregset_t *);
 #define ELF_ET_DYN_BASE         (TASK_SIZE / 3 * 2)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* _ASM_ELF_H */
diff --git a/include/asm-parisc/elf.h b/include/asm-parisc/elf.h
index f628ac7..9807cae 100644
--- a/include/asm-parisc/elf.h
+++ b/include/asm-parisc/elf.h
@@ -344,4 +344,8 @@ struct pt_regs;	/* forward declaration... */
 #define ELF_HWCAP	0
 /* (boot_cpu_data.x86_capability) */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-powerpc/elf.h b/include/asm-powerpc/elf.h
index de50799..af45d0e 100644
--- a/include/asm-powerpc/elf.h
+++ b/include/asm-powerpc/elf.h
@@ -422,4 +422,8 @@ extern void arch_write_notes(struct file *file);
 #define ARCH_HAVE_EXTRA_ELF_NOTES
 #endif /* CONFIG_PPC_CELL */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* _ASM_POWERPC_ELF_H */
diff --git a/include/asm-s390/elf.h b/include/asm-s390/elf.h
index 91d0632..0a32ac3 100644
--- a/include/asm-s390/elf.h
+++ b/include/asm-s390/elf.h
@@ -216,4 +216,8 @@ do {							\
 #endif /* __s390x__ */
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
diff --git a/include/asm-sh/elf.h b/include/asm-sh/elf.h
index 43ca244..f055a68 100644
--- a/include/asm-sh/elf.h
+++ b/include/asm-sh/elf.h
@@ -140,4 +140,8 @@ do {								\
 } while (0)
 #endif /* CONFIG_VSYSCALL */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* __ASM_SH_ELF_H */
diff --git a/include/asm-sh64/elf.h b/include/asm-sh64/elf.h
index f994286..5d6dd4b 100644
--- a/include/asm-sh64/elf.h
+++ b/include/asm-sh64/elf.h
@@ -104,4 +104,8 @@ typedef struct user_fpu_struct elf_fpregset_t;
 #define SET_PERSONALITY(ex, ibcs2) set_personality(PER_LINUX_32BIT)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* __ASM_SH64_ELF_H */
diff --git a/include/asm-sparc/elf.h b/include/asm-sparc/elf.h
index aaf6ef4..94b273d 100644
--- a/include/asm-sparc/elf.h
+++ b/include/asm-sparc/elf.h
@@ -168,4 +168,8 @@ do {	unsigned long *dest = &(__elf_regs[0]);		\
 
 #endif /* __KERNEL__ */
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* !(__ASMSPARC_ELF_H) */
diff --git a/include/asm-sparc64/elf.h b/include/asm-sparc64/elf.h
index 303d85e..8afe25f 100644
--- a/include/asm-sparc64/elf.h
+++ b/include/asm-sparc64/elf.h
@@ -190,4 +190,8 @@ do {	unsigned long new_flags = current_thread_info()->flags; \
 } while (0)
 #endif
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif /* !(__ASM_SPARC64_ELF_H) */
diff --git a/include/asm-um/elf-x86_64.h b/include/asm-um/elf-x86_64.h
index 8a8246d..e1d664e 100644
--- a/include/asm-um/elf-x86_64.h
+++ b/include/asm-um/elf-x86_64.h
@@ -81,6 +81,10 @@ extern long elf_aux_hwcap;
 
 #define SET_PERSONALITY(ex, ibcs2) do ; while(0)
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif
 
 /*
diff --git a/include/asm-x86_64/elf.h b/include/asm-x86_64/elf.h
index b4fbe47..5a1adf9 100644
--- a/include/asm-x86_64/elf.h
+++ b/include/asm-x86_64/elf.h
@@ -177,4 +177,6 @@ do if (vdso_enabled) {						\
 
 #endif
 
+extern void arch_randomize_brk(void);
+
 #endif
diff --git a/include/asm-xtensa/elf.h b/include/asm-xtensa/elf.h
index 1569b53..10e60bf 100644
--- a/include/asm-xtensa/elf.h
+++ b/include/asm-xtensa/elf.h
@@ -222,5 +222,9 @@ extern void do_save_fpregs (elf_fpregset_t*, struct pt_regs*,
 extern int do_restore_fpregs (elf_fpregset_t*, struct pt_regs*,
 			      struct task_struct*);
 
+static inline void arch_randomize_brk(void)
+{
+}
+
 #endif	/* __KERNEL__ */
 #endif	/* _XTENSA_ELF_H */
-
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