The patch below replaces the existing 8Kb randomisation of the userspace
stack pointer (which is currently only done for Hyperthreaded P-IVs) with a
more general randomisation over a 64Kb range.
Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]>
diff -purN linux-step-2/arch/i386/kernel/process.c
linux-step-4/arch/i386/kernel/process.c
--- linux-step-2/arch/i386/kernel/process.c 2005-01-26 18:24:35.472822000
+0100
+++ linux-step-4/arch/i386/kernel/process.c 2005-01-26 21:22:00.465537920
+0100
@@ -36,6 +36,7 @@
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/ptrace.h>
+#include <linux/random.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
@@ -828,3 +829,9 @@ asmlinkage int sys_get_thread_area(struc
return 0;
}
+unsigned long arch_align_stack(unsigned long sp)
+{
+ if (randomize_va_space)
+ sp -= ((get_random_int() % 4096) << 4);
+ return sp & ~0xf;
+}
diff -purN linux-step-2/arch/x86_64/kernel/process.c
linux-step-4/arch/x86_64/kernel/process.c
--- linux-step-2/arch/x86_64/kernel/process.c 2005-01-26 18:24:49.000000000
+0100
+++ linux-step-4/arch/x86_64/kernel/process.c 2005-01-26 20:48:02.000000000
+0100
@@ -743,3 +743,10 @@ int dump_task_regs(struct task_struct *t
return 1;
}
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+ if (randomize_vs_space)
+ sp -= ((get_random_int() % 4096) << 4);
+ return sp & ~0xf;
+}
diff -purN linux-step-2/fs/binfmt_elf.c linux-step-4/fs/binfmt_elf.c
--- linux-step-2/fs/binfmt_elf.c 2005-01-26 21:14:51.464755952 +0100
+++ linux-step-4/fs/binfmt_elf.c 2005-01-26 21:18:49.017642424 +0100
@@ -165,20 +165,14 @@ create_elf_tables(struct linux_binprm *b
if (k_platform) {
size_t len = strlen(k_platform) + 1;
-#ifdef CONFIG_X86_HT
+#ifdef __HAVE_ARCH_ALIGN_STACK
/*
* In some cases (e.g. Hyper-Threading), we want to avoid L1
* evictions by the processes running on the same package. One
* thing we can do is to shuffle the initial stack for them.
- *
- * The conditionals here are unneeded, but kept in to make the
- * code behaviour the same as pre change unless we have
- * hyperthreaded processors. This should be cleaned up
- * before 2.6
*/
- if (smp_num_siblings > 1)
- STACK_ALLOC(p, ((current->pid % 64) << 7));
+ p = arch_align_stack((unsigned long)p);
#endif
u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
if (__copy_to_user(u_platform, k_platform, len))
diff -purN linux-step-2/fs/exec.c linux-step-4/fs/exec.c
--- linux-step-2/fs/exec.c 2005-01-26 21:15:33.860310848 +0100
+++ linux-step-4/fs/exec.c 2005-01-26 21:25:22.678796832 +0100
@@ -400,7 +400,12 @@ int setup_arg_pages(struct linux_binprm
while (i < MAX_ARG_PAGES)
bprm->page[i++] = NULL;
#else
- stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE;
+#ifdef __HAVE_ARCH_ALIGN_STACK
+ stack_base = arch_align_stack(STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE);
+ stack_base = PAGE_ALIGN(stack_base);
+#else
+ stack_base = STACK_TOP - MAX_ARG_PAGES * PAGE_SIZE;
+#endif
bprm->p += stack_base;
mm->arg_start = bprm->p;
arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
diff -purN linux-step-2/include/asm-i386/system.h
linux-step-4/include/asm-i386/system.h
--- linux-step-2/include/asm-i386/system.h 2005-01-26 18:24:39.226252000
+0100
+++ linux-step-4/include/asm-i386/system.h 2005-01-26 20:49:59.000000000
+0100
@@ -468,4 +468,7 @@ void enable_hlt(void);
extern int es7000_plat;
void cpu_idle_wait(void);
+#define __HAVE_ARCH_ALIGN_STACK
+extern unsigned long arch_align_stack(unsigned long sp);
+
#endif
diff -purN linux-step-2/include/asm-x86_64/system.h
linux-step-4/include/asm-x86_64/system.h
--- linux-step-2/include/asm-x86_64/system.h 2005-01-26 18:24:39.000000000
+0100
+++ linux-step-4/include/asm-x86_64/system.h 2005-01-26 20:50:14.000000000
+0100
@@ -338,4 +338,7 @@ void enable_hlt(void);
#define HAVE_EAT_KEY
void eat_key(void);
+#define __HAVE_ARCH_ALIGN_STACK
+extern unsigned long arch_align_stack(unsigned long sp);
+
#endif
-
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