From: Andi Kleen <ak@suse.de>
Date: Tue, 26 Sep 2006 08:52:28 +0000 (+0200)
Subject: [PATCH] i386/x86-64: Don't randomize stack top when no randomization personality... 
X-Git-Tag: v2.6.19-rc1~1077^2~193
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c16b63e09d9d03158e0a92e961234e94c4862620;p=linux-2.6

[PATCH] i386/x86-64: Don't randomize stack top when no randomization personality is set

Based on patch from Frank van Maarseveen <frankvm@frankvm.com>, but
extended.

Signed-off-by: Andi Kleen <ak@suse.de>
---

diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 8657c73965..b741c3e1a5 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -37,6 +37,7 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
+#include <linux/personality.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -905,7 +906,7 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
 
 unsigned long arch_align_stack(unsigned long sp)
 {
-	if (randomize_va_space)
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 		sp -= get_random_int() % 8192;
 	return sp & ~0xf;
 }
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 6e0527635b..6fbd19564e 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -845,7 +845,7 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
 
 unsigned long arch_align_stack(unsigned long sp)
 {
-	if (randomize_va_space)
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 		sp -= get_random_int() % 8192;
 	return sp & ~0xf;
 }
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 672a3b90bc..5109dbff93 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -515,7 +515,8 @@ static unsigned long randomize_stack_top(unsigned long stack_top)
 {
 	unsigned int random_variable = 0;
 
-	if (current->flags & PF_RANDOMIZE) {
+	if ((current->flags & PF_RANDOMIZE) &&
+		!(current->personality & ADDR_NO_RANDOMIZE)) {
 		random_variable = get_random_int() & STACK_RND_MASK;
 		random_variable <<= PAGE_SHIFT;
 	}