On Sun, Feb 10, 2008 at 08:43:32PM -0500, Kyle McMartin wrote:
> x86-merge has kind of thrown a spanner in the execshield patchset. I've
> merged it up so it looks like it works, but I'd like to get some input
> from others to make sure I didn't brown-paper-bag it.
> 
> The randomization bits seem to have been merged upstream, but I deferred
> to the execshield implementation since they had some differences.
> 
> cheers,
>       Kyle
> [linux-2.6-execshield.patch is attached.]

i appear to have noviced it and truncated the patch. i remerged it
against rc1... seems to work. i hope...

cheers,
        kyle
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index f86a3c4..4c5f70d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -478,6 +478,13 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
         * we do "generic changes."
         */
 
+       if (exec_shield != 0) {
+#ifdef CONFIG_X86_PAE
+               if (!test_bit(X86_FEATURE_NX, c->x86_capability))
+#endif
+               clear_bit(X86_FEATURE_SEP, c->x86_capability);
+       }
+
        /* If the model name is still unset, do table lookup. */
        if ( !c->x86_model_id[0] ) {
                char *p;
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index a7d50a5..83f7b4e 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -677,7 +677,8 @@ struct task_struct * __switch_to(struct task_struct 
*prev_p, struct task_struct
        /* never put a printk in __switch_to... printk() calls wake_up*() 
indirectly */
 
        __unlazy_fpu(prev_p);
-
+       if (next_p->mm)
+               load_user_cs_desc(cpu, next_p->mm);
 
        /* we're going to use this soon, after a few expensive things */
        if (next_p->fpu_counter > 5)
@@ -842,8 +843,58 @@ unsigned long arch_align_stack(unsigned long sp)
        return sp & ~0xf;
 }
 
-unsigned long arch_randomize_brk(struct mm_struct *mm)
+void arch_add_exec_range(struct mm_struct *mm, unsigned long limit)
+{
+       if (limit > mm->context.exec_limit) {
+               mm->context.exec_limit = limit;
+               set_user_cs(&mm->context.user_cs, limit);
+               if (mm == current->mm) {
+                       preempt_disable();
+                       load_user_cs_desc(smp_processor_id(), mm);
+                       preempt_enable();
+               }
+       }
+}
+
+void arch_remove_exec_range(struct mm_struct *mm, unsigned long old_end)
 {
-       unsigned long range_end = mm->brk + 0x02000000;
-       return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+       struct vm_area_struct *vma;
+       unsigned long limit = PAGE_SIZE;
+
+       if (old_end == mm->context.exec_limit) {
+               for (vma = mm->mmap; vma; vma = vma->vm_next)
+                       if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))
+                               limit = vma->vm_end;
+
+               mm->context.exec_limit = limit;
+               set_user_cs(&mm->context.user_cs, limit);
+               if (mm == current->mm) {
+                       preempt_disable();
+                       load_user_cs_desc(smp_processor_id(), mm);
+                       preempt_enable();
+               }
+       }
+}
+
+void arch_flush_exec_range(struct mm_struct *mm)
+{
+       mm->context.exec_limit = 0;
+       set_user_cs(&mm->context.user_cs, 0);
+}
+
+/*
+ * Generate random brk address between 128MB and 196MB. (if the layout
+ * allows it.)
+ */
+void randomize_brk(unsigned long old_brk)
+{
+       unsigned long new_brk, range_start, range_end;
+
+       range_start = 0x08000000;
+       if (current->mm->brk >= range_start)
+               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 = new_brk;
 }
diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c
index 309366f..8a940dc 100644
--- a/arch/x86/kernel/setup64.c
+++ b/arch/x86/kernel/setup64.c
@@ -45,46 +45,6 @@ EXPORT_SYMBOL_GPL(__supported_pte_mask);
 
 static int do_not_nx __cpuinitdata = 0;
 
-/* noexec=on|off
-Control non executable mappings for 64bit processes.
-
-on     Enable(default)
-off    Disable
-*/ 
-static int __init nonx_setup(char *str)
-{
-       if (!str)
-               return -EINVAL;
-       if (!strncmp(str, "on", 2)) {
-                __supported_pte_mask |= _PAGE_NX; 
-               do_not_nx = 0; 
-       } else if (!strncmp(str, "off", 3)) {
-               do_not_nx = 1;
-               __supported_pte_mask &= ~_PAGE_NX;
-        }
-       return 0;
-} 
-early_param("noexec", nonx_setup);
-
-int force_personality32 = 0; 
-
-/* noexec32=on|off
-Control non executable heap for 32bit processes.
-To control the stack too use noexec=off
-
-on     PROT_READ does not imply PROT_EXEC for 32bit processes
-off    PROT_READ implies PROT_EXEC (default)
-*/
-static int __init nonx32_setup(char *str)
-{
-       if (!strcmp(str, "on"))
-               force_personality32 &= ~READ_IMPLIES_EXEC;
-       else if (!strcmp(str, "off"))
-               force_personality32 |= READ_IMPLIES_EXEC;
-       return 1;
-}
-__setup("noexec32=", nonx32_setup);
-
 /*
  * Copy data used in early init routines from the initial arrays to the
  * per cpu data areas.  These arrays then become expendable and the
diff --git a/arch/x86/kernel/smp_32.c b/arch/x86/kernel/smp_32.c
index dc0cde9..cca75b4 100644
--- a/arch/x86/kernel/smp_32.c
+++ b/arch/x86/kernel/smp_32.c
@@ -22,6 +22,7 @@
 
 #include <asm/mtrr.h>
 #include <asm/tlbflush.h>
+#include <asm/desc.h>
 #include <asm/mmu_context.h>
 #include <mach_apic.h>
 
@@ -316,6 +317,8 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
        unsigned long cpu;
 
        cpu = get_cpu();
+       if (current->active_mm)
+               load_user_cs_desc(cpu, current->active_mm);
 
        if (!cpu_isset(cpu, flush_cpumask))
                goto out;
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index b22c01e..7e196e4 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -592,7 +592,91 @@ DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
 DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)
 DO_ERROR(12, SIGBUS,  "stack segment", stack_segment)
 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
-DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)
+
+/*
+ * lazy-check for CS validity on exec-shield binaries:
+ *
+ * the original non-exec stack patch was written by
+ * Solar Designer <solar at openwall.com>. Thanks!
+ */
+static int
+check_lazy_exec_limit(int cpu, struct pt_regs *regs, long error_code)
+{
+       struct desc_struct *desc1, *desc2;
+       struct vm_area_struct *vma;
+       unsigned long limit;
+
+       if (current->mm == NULL)
+               return 0;
+
+       limit = -1UL;
+       if (current->mm->context.exec_limit != -1UL) {
+               limit = PAGE_SIZE;
+               spin_lock(&current->mm->page_table_lock);
+               for (vma = current->mm->mmap; vma; vma = vma->vm_next)
+                       if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))
+                               limit = vma->vm_end;
+               vma = get_gate_vma(current);
+               if (vma && (vma->vm_flags & VM_EXEC) && (vma->vm_end > limit))
+                       limit = vma->vm_end;
+               spin_unlock(&current->mm->page_table_lock);
+               if (limit >= TASK_SIZE)
+                       limit = -1UL;
+               current->mm->context.exec_limit = limit;
+       }
+       set_user_cs(&current->mm->context.user_cs, limit);
+
+       desc1 = &current->mm->context.user_cs;
+       desc2 = get_cpu_gdt_table(cpu) + GDT_ENTRY_DEFAULT_USER_CS;
+
+       if (desc1->a != desc2->a || desc1->b != desc2->b) {
+               /*
+                * The CS was not in sync - reload it and retry the
+                * instruction. If the instruction still faults then
+                * we won't hit this branch next time around.
+                */
+               if (print_fatal_signals >= 2) {
+                       printk(KERN_ERR "#GPF fixup (%ld[seg:%lx]) at %08lx, 
CPU#%d.\n",
+                               error_code, error_code/8, regs->ip, 
smp_processor_id());
+                       printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x, 
CPU_cs: %08x/%08x.\n",
+                               current->mm->context.exec_limit, desc1->a, 
desc1->b, desc2->a, desc2->b);
+               }
+               load_user_cs_desc(cpu, current->mm);
+               return 1;
+       }
+
+       return 0;
+}
+
+/*
+ * The fixup code for errors in iret jumps to here (iret_exc).  It loses
+ * the original trap number and error code.  The bogus trap 32 and error
+ * code 0 are what the vanilla kernel delivers via:
+ * DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)
+ *
+ * NOTE: Because of the final "1" in the macro we need to enable interrupts.
+ *
+ * In case of a general protection fault in the iret instruction, we
+ * need to check for a lazy CS update for exec-shield.
+ */
+fastcall void do_iret_error(struct pt_regs *regs, long error_code)
+{
+       int ok;
+       local_irq_enable();
+       ok = check_lazy_exec_limit(get_cpu(), regs, error_code);
+       put_cpu();
+       if (!ok && notify_die(DIE_TRAP, "iret exception", regs,
+           error_code, 32, SIGSEGV) != NOTIFY_STOP) {
+               siginfo_t info;
+               info.si_signo = SIGSEGV;
+               info.si_errno = 0;
+               info.si_code = ILL_BADSTK;
+               info.si_addr = 0;
+               do_trap(32, SIGSEGV, "iret exception", 0, regs, error_code,
+                       &info);
+       }
+}
+
 
 void __kprobes do_general_protection(struct pt_regs * regs,
                                              long error_code)
@@ -600,6 +684,7 @@ void __kprobes do_general_protection(struct pt_regs * regs,
        int cpu = get_cpu();
        struct tss_struct *tss = &per_cpu(init_tss, cpu);
        struct thread_struct *thread = &current->thread;
+       int ok;
 
        /*
         * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
@@ -626,7 +711,6 @@ void __kprobes do_general_protection(struct pt_regs * regs,
                put_cpu();
                return;
        }
-       put_cpu();
 
        if (regs->flags & VM_MASK)
                goto gp_in_vm86;
@@ -634,6 +718,22 @@ void __kprobes do_general_protection(struct pt_regs * regs,
        if (!user_mode(regs))
                goto gp_in_kernel;
 
+       ok = check_lazy_exec_limit(cpu, regs, error_code);
+
+       put_cpu();
+
+       if (ok)
+               return;
+
+       if (print_fatal_signals) {
+               printk(KERN_ERR "#GPF(%ld[seg:%lx]) at %08lx, CPU#%d.\n", 
error_code,
+                       error_code/8, regs->ip, smp_processor_id());
+               printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x.\n",
+                       current->mm->context.exec_limit,
+                       current->mm->context.user_cs.a,
+                       current->mm->context.user_cs.b);
+       }
+
        current->thread.error_code = error_code;
        current->thread.trap_no = 13;
        if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) &&
@@ -650,11 +750,13 @@ void __kprobes do_general_protection(struct pt_regs * 
regs,
        return;
 
 gp_in_vm86:
+       put_cpu();
        local_irq_enable();
        handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
        return;
 
 gp_in_kernel:
+       put_cpu();
        if (!fixup_exception(regs)) {
                current->thread.error_code = error_code;
                current->thread.trap_no = 13;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 8106bba..23932be 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -473,7 +473,7 @@ static int disable_nx __initdata;
  * Control non executable mappings.
  *
  * on      Enable
- * off     Disable
+ * off     Disable (disables exec-shield too)
  */
 static int __init noexec_setup(char *str)
 {
@@ -482,14 +482,12 @@ static int __init noexec_setup(char *str)
                        __supported_pte_mask |= _PAGE_NX;
                        disable_nx = 0;
                }
-       } else {
-               if (!strcmp(str, "off")) {
-                       disable_nx = 1;
-                       __supported_pte_mask &= ~_PAGE_NX;
-               } else {
-                       return -EINVAL;
-               }
-       }
+       } else if (!strcmp(str,"off")) {
+               disable_nx = 1;
+               __supported_pte_mask &= ~_PAGE_NX;
+               exec_shield = 0;
+       } else
+               return -EINVAL;
 
        return 0;
 }
@@ -527,6 +525,10 @@ void __init paging_init(void)
        if (nx_enabled)
                printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 #endif
+       if (exec_shield)
+               printk(KERN_INFO "Using x86 segment limits to approximate "
+                       "NX protection\n");
+
        pagetable_init();
 
        load_cr3(swapper_pg_dir);
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 56fe712..ec932ae 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -111,13 +111,15 @@ static unsigned long mmap_legacy_base(void)
  */
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
-       if (mmap_is_legacy()) {
+       if (!(2 & exec_shield) && mmap_is_legacy()) {
                mm->mmap_base = mmap_legacy_base();
                mm->get_unmapped_area = arch_get_unmapped_area;
                mm->unmap_area = arch_unmap_area;
        } else {
                mm->mmap_base = mmap_base();
                mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+               if (!(current->personality & READ_IMPLIES_EXEC))
+                       mm->get_unmapped_exec_area = 
arch_get_unmapped_exec_area;
                mm->unmap_area = arch_unmap_area_topdown;
        }
 }
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 348f134..0bd5f44 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -336,7 +336,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
int exstack)
        if (compat)
                addr = VDSO_HIGH_BASE;
        else {
-               addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
+               addr = get_unmapped_area_prot(NULL, 0, PAGE_SIZE, 0, 0, 1);
                if (IS_ERR_VALUE(addr)) {
                        ret = addr;
                        goto up_fail;
diff --git a/drivers/char/random.c b/drivers/char/random.c
index f43c89f..4ee8491 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1638,13 +1638,19 @@ EXPORT_SYMBOL(secure_dccp_sequence_number);
  */
 unsigned int get_random_int(void)
 {
+       unsigned int val = 0;
+
+#ifdef CONFIG_X86_HAS_TSC
+       rdtscl(val);
+#endif
+
        /*
         * Use IP's RNG. It suits our purpose perfectly: it re-keys itself
         * every second, from the entropy pool (and thus creates a limited
         * drain on it), and uses halfMD4Transform within the second. We
         * also mix it with jiffies and the PID:
         */
-       return secure_ip_id((__force __be32)(current->pid + jiffies));
+       return secure_ip_id((__force __be32)(current->pid + jiffies  + 
(int)val));
 }
 
 /*
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 41a958a..22cbd06 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -81,7 +81,7 @@ static struct linux_binfmt elf_format = {
                .hasvdso        = 1
 };
 
-#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
+#define BAD_ADDR(x) IS_ERR_VALUE(x)
 
 static int set_brk(unsigned long start, unsigned long end)
 {
@@ -544,7 +544,7 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
        unsigned long start_code, end_code, start_data, end_data;
        unsigned long reloc_func_desc = 0;
        struct files_struct *files;
-       int executable_stack = EXSTACK_DEFAULT;
+       int executable_stack;
        unsigned long def_flags = 0;
        struct {
                struct elfhdr elf_ex;
@@ -611,6 +611,8 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
        fd_install(elf_exec_fileno = retval, bprm->file);
 
        elf_ppnt = elf_phdata;
+       executable_stack = EXSTACK_DEFAULT;
+
        elf_bss = 0;
        elf_brk = 0;
 
@@ -709,6 +711,11 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
                        break;
                }
 
+       if (current->personality == PER_LINUX && (exec_shield & 2)) {
+               executable_stack = EXSTACK_DISABLE_X;
+               current->flags |= PF_RANDOMIZE;
+       }
+
        /* Some simple consistency checks for the interpreter */
        if (elf_interpreter) {
                retval = -ELIBBAD;
@@ -728,6 +735,15 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
        if (retval)
                goto out_free_dentry;
 
+#ifdef CONFIG_X86_32
+       /*
+        * Turn off the CS limit completely if exec-shield disabled or
+        * NX active:
+        */
+       if (!exec_shield || executable_stack != EXSTACK_DISABLE_X || nx_enabled)
+               arch_add_exec_range(current->mm, -1);
+#endif
+
        /* Discard our unneeded old files struct */
        if (files) {
                put_files_struct(files);
@@ -741,7 +757,8 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
        /* Do this immediately, since STACK_TOP as used in setup_arg_pages
           may depend on the personality.  */
        SET_PERSONALITY(loc->elf_ex, 0);
-       if (elf_read_implies_exec(loc->elf_ex, executable_stack))
+       if (!(exec_shield & 2) &&
+                       elf_read_implies_exec(loc->elf_ex, executable_stack))
                current->personality |= READ_IMPLIES_EXEC;
 
        if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
@@ -906,7 +923,7 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
                                            interpreter,
                                            &interp_map_addr,
                                            load_bias);
-               if (!IS_ERR((void *)elf_entry)) {
+               if (!BAD_ADDR(elf_entry)) {
                        /*
                         * load_elf_interp() returns relocation
                         * adjustment
@@ -914,12 +931,14 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
                        interp_load_addr = elf_entry;
                        elf_entry += loc->interp_elf_ex.e_entry;
                }
+       
                if (BAD_ADDR(elf_entry)) {
                        force_sig(SIGSEGV, current);
                        retval = IS_ERR((void *)elf_entry) ?
-                                       (int)elf_entry : -EINVAL;
+                               (int)elf_entry : -EINVAL;
                        goto out_free_dentry;
                }
+
                reloc_func_desc = interp_load_addr;
 
                allow_write_access(interpreter);
@@ -934,20 +953,21 @@ static int load_elf_binary(struct linux_binprm *bprm, 
struct pt_regs *regs)
                }
        }
 
-       kfree(elf_phdata);
-
        sys_close(elf_exec_fileno);
 
        set_binfmt(&elf_format);
 
 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
        retval = arch_setup_additional_pages(bprm, executable_stack);
+
        if (retval < 0) {
                send_sig(SIGKILL, current, 0);
-               goto out;
+               goto out_free_fh;
        }
 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
 
+       kfree(elf_phdata);
+
        compute_creds(bprm);
        current->flags &= ~PF_FORKNOEXEC;
        retval = create_elf_tables(bprm, &loc->elf_ex,
@@ -963,10 +983,9 @@ 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;
 
-#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 __HAVE_ARCH_RANDOMIZE_BRK
+       if (current->flags & PF_RANDOMIZE)
+               randomize_brk(elf_brk);
 #endif
 
        if (current->personality & MMAP_PAGE_ZERO) {
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 07d6c48..46adc3b 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -471,8 +471,12 @@ static int do_task_stat(struct seq_file *m, struct 
pid_namespace *ns,
        }
        rcu_read_unlock();
 
-       if (!whole || num_threads < 2)
-               wchan = get_wchan(task);
+       if (!whole || num_threads < 2) {
+               wchan = 0;
+               if (current->uid == task->uid || current->euid == task->uid ||
+                       capable(CAP_SYS_NICE))
+                               wchan = get_wchan(task);
+       }
        if (!whole) {
                min_flt = task->min_flt;
                maj_flt = task->maj_flt;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 7c6b4ec..877d0a2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2290,7 +2290,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        INF("cmdline",    S_IRUGO, pid_cmdline),
        ONE("stat",       S_IRUGO, tgid_stat),
        ONE("statm",      S_IRUGO, pid_statm),
-       REG("maps",       S_IRUGO, maps),
+       REG("maps",       S_IRUSR, maps),
 #ifdef CONFIG_NUMA
        REG("numa_maps",  S_IRUGO, numa_maps),
 #endif
@@ -2302,7 +2302,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        REG("mountstats", S_IRUSR, mountstats),
 #ifdef CONFIG_PROC_PAGE_MONITOR
        REG("clear_refs", S_IWUSR, clear_refs),
-       REG("smaps",      S_IRUGO, smaps),
+       REG("smaps",      S_IRUSR, smaps),
        REG("pagemap",    S_IRUSR, pagemap),
 #endif
 #ifdef CONFIG_SECURITY
@@ -2621,7 +2621,7 @@ static const struct pid_entry tid_base_stuff[] = {
        INF("cmdline",   S_IRUGO, pid_cmdline),
        ONE("stat",      S_IRUGO, tid_stat),
        ONE("statm",     S_IRUGO, pid_statm),
-       REG("maps",      S_IRUGO, maps),
+       REG("maps",      S_IRUSR, maps),
 #ifdef CONFIG_NUMA
        REG("numa_maps", S_IRUGO, numa_maps),
 #endif
@@ -2632,7 +2632,7 @@ static const struct pid_entry tid_base_stuff[] = {
        REG("mounts",    S_IRUGO, mounts),
 #ifdef CONFIG_PROC_PAGE_MONITOR
        REG("clear_refs", S_IWUSR, clear_refs),
-       REG("smaps",     S_IRUGO, smaps),
+       REG("smaps",     S_IRUSR, smaps),
        REG("pagemap",    S_IRUSR, pagemap),
 #endif
 #ifdef CONFIG_SECURITY
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ae4d3f2..9a838b8 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -48,7 +48,11 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                "VmStk:\t%8lu kB\n"
                "VmExe:\t%8lu kB\n"
                "VmLib:\t%8lu kB\n"
-               "VmPTE:\t%8lu kB\n",
+               "VmPTE:\t%8lu kB\n"
+               "StaBrk:\t%08lx kB\n"
+               "Brk:\t%08lx kB\n"
+               "StaStk:\t%08lx kB\n"
+               ,
                hiwater_vm << (PAGE_SHIFT-10),
                (total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
                mm->locked_vm << (PAGE_SHIFT-10),
@@ -56,7 +60,12 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                total_rss << (PAGE_SHIFT-10),
                data << (PAGE_SHIFT-10),
                mm->stack_vm << (PAGE_SHIFT-10), text, lib,
-               (PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10);
+               (PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10,
+               mm->start_brk, mm->brk, mm->start_stack);
+#ifdef CONFIG_X86_32
+       if (!nx_enabled)
+               seq_printf(m, "ExecLim:\t%08lx\n", mm->context.exec_limit);
+#endif
 }
 
 unsigned long task_vsize(struct mm_struct *mm)
@@ -238,6 +247,9 @@ static int show_map(struct seq_file *m, void *v)
 {
        struct proc_maps_private *priv = m->private;
        struct task_struct *task = priv->task;
+#ifdef CONFIG_X86_32
+       struct mm_struct *tmm = get_task_mm(task);
+#endif
        struct vm_area_struct *vma = v;
        struct mm_struct *mm = vma->vm_mm;
        struct file *file = vma->vm_file;
@@ -260,10 +272,20 @@ static int show_map(struct seq_file *m, void *v)
                        vma->vm_end,
                        flags & VM_READ ? 'r' : '-',
                        flags & VM_WRITE ? 'w' : '-',
-                       flags & VM_EXEC ? 'x' : '-',
+                       (flags & VM_EXEC
+#ifdef CONFIG_X86_32
+                               || (!nx_enabled && tmm &&
+                               (vma->vm_start < tmm->context.exec_limit))
+#endif
+                       )
+                               ? 'x' : '-',
                        flags & VM_MAYSHARE ? 's' : 'p',
                        vma->vm_pgoff << PAGE_SHIFT,
                        MAJOR(dev), MINOR(dev), ino, &len);
+#ifdef CONFIG_X86_32
+       if (tmm)
+               mmput(tmm);
+#endif
 
        /*
         * Print the dentry name for named mappings, and a
diff --git a/include/asm-ia64/pgalloc.h b/include/asm-ia64/pgalloc.h
index b9ac1a6..24f183a 100644
--- a/include/asm-ia64/pgalloc.h
+++ b/include/asm-ia64/pgalloc.h
@@ -1,6 +1,10 @@
 #ifndef _ASM_IA64_PGALLOC_H
 #define _ASM_IA64_PGALLOC_H
 
+#define arch_add_exec_range(mm, limit)         do { ; } while (0)
+#define arch_flush_exec_range(mm)              do { ; } while (0)
+#define arch_remove_exec_range(mm, limit)      do { ; } while (0)
+
 /*
  * This file contains the functions and defines necessary to allocate
  * page tables.
diff --git a/include/asm-powerpc/pgalloc.h b/include/asm-powerpc/pgalloc.h
index b4505ed..25068ae 100644
--- a/include/asm-powerpc/pgalloc.h
+++ b/include/asm-powerpc/pgalloc.h
@@ -2,6 +2,11 @@
 #define _ASM_POWERPC_PGALLOC_H
 #ifdef __KERNEL__
 
+/* Dummy functions since we don't support execshield on ppc */
+#define arch_add_exec_range(mm, limit) do { ; } while (0)
+#define arch_flush_exec_range(mm)      do { ; } while (0)
+#define arch_remove_exec_range(mm, limit) do { ; } while (0)
+
 #ifdef CONFIG_PPC64
 #include <asm/pgalloc-64.h>
 #else
diff --git a/include/asm-ppc/pgalloc.h b/include/asm-ppc/pgalloc.h
index fd4d1d7..de55ad5 100644
--- a/include/asm-ppc/pgalloc.h
+++ b/include/asm-ppc/pgalloc.h
@@ -41,5 +41,10 @@ extern void pte_free(struct mm_struct *mm, pgtable_t pte);
 
 #define check_pgt_cache()      do { } while (0)
 
+#define arch_add_exec_range(mm, limit)         do { ; } while (0)
+#define arch_flush_exec_range(mm)              do { ; } while (0)
+#define arch_remove_exec_range(mm, limit)      do { ; } while (0)
+
+
 #endif /* _PPC_PGALLOC_H */
 #endif /* __KERNEL__ */
diff --git a/include/asm-s390/pgalloc.h b/include/asm-s390/pgalloc.h
index f5b2bf3..a43f0ec 100644
--- a/include/asm-s390/pgalloc.h
+++ b/include/asm-s390/pgalloc.h
@@ -17,6 +17,10 @@
 #include <linux/gfp.h>
 #include <linux/mm.h>
 
+#define arch_add_exec_range(mm, limit) do { ; } while (0)
+#define arch_flush_exec_range(mm)      do { ; } while (0)
+#define arch_remove_exec_range(mm, limit) do { ; } while (0)
+
 #define check_pgt_cache()      do {} while (0)
 
 unsigned long *crst_table_alloc(struct mm_struct *, int);
diff --git a/include/asm-sparc/pgalloc.h b/include/asm-sparc/pgalloc.h
index 6292cd0..2632807 100644
--- a/include/asm-sparc/pgalloc.h
+++ b/include/asm-sparc/pgalloc.h
@@ -66,4 +66,8 @@ BTFIXUPDEF_CALL(void, pte_free, pgtable_t )
 #define pte_free(mm, pte)      BTFIXUP_CALL(pte_free)(pte)
 #define __pte_free_tlb(tlb, pte)       pte_free((tlb)->mm, pte)
 
+#define arch_add_exec_range(mm, limit)         do { ; } while (0)
+#define arch_flush_exec_range(mm)              do { ; } while (0)
+#define arch_remove_exec_range(mm, limit)      do { ; } while (0)
+
 #endif /* _SPARC_PGALLOC_H */
diff --git a/include/asm-sparc64/pgalloc.h b/include/asm-sparc64/pgalloc.h
index 3ee2d40..c998da2 100644
--- a/include/asm-sparc64/pgalloc.h
+++ b/include/asm-sparc64/pgalloc.h
@@ -79,4 +79,8 @@ static inline void check_pgt_cache(void)
        quicklist_trim(0, NULL, 25, 16);
 }
 
+#define arch_add_exec_range(mm, limit)         do { ; } while (0)
+#define arch_flush_exec_range(mm)              do { ; } while (0)
+#define arch_remove_exec_range(mm, limit)      do { ; } while (0)
+
 #endif /* _SPARC64_PGALLOC_H */
diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h
index 5b6a05d..7ad80b9 100644
--- a/include/asm-x86/desc.h
+++ b/include/asm-x86/desc.h
@@ -353,6 +353,22 @@ static inline void set_system_gate_ist(int n, void *addr, 
unsigned ist)
        _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 }
 
+static inline void set_user_cs(struct desc_struct *desc, unsigned long limit)
+{
+       limit = (limit - 1) / PAGE_SIZE;
+       desc->a = limit & 0xffff;
+       desc->b = (limit & 0xf0000) | 0x00c0fb00;
+}
+
+#define load_user_cs_desc(cpu, mm) \
+       get_cpu_gdt_table(cpu)[GDT_ENTRY_DEFAULT_USER_CS] = 
(mm)->context.user_cs
+
+#ifdef CONFIG_X86_32
+extern void arch_add_exec_range(struct mm_struct *mm, unsigned long limit);
+extern void arch_remove_exec_range(struct mm_struct *mm, unsigned long limit);
+extern void arch_flush_exec_range(struct mm_struct *mm);
+#endif /* CONFIG_X86_32 */
+
 #else
 /*
  * GET_DESC_BASE reads the descriptor base of the specified segment.
diff --git a/include/asm-x86/elf.h b/include/asm-x86/elf.h
index fb62f99..516a9da 100644
--- a/include/asm-x86/elf.h
+++ b/include/asm-x86/elf.h
@@ -185,7 +185,6 @@ static inline void elf_common_init(struct thread_struct *t,
                        clear_thread_flag(TIF_ABI_PENDING);     \
                else                                            \
                        set_thread_flag(TIF_ABI_PENDING);       \
-               current->personality |= force_personality32;    \
        } while (0)
 #define COMPAT_ELF_PLATFORM                    ("i686")
 
@@ -230,7 +229,6 @@ static inline void elf_common_init(struct thread_struct *t,
 #define ELF_PLATFORM       ("x86_64")
 extern void set_personality_64bit(void);
 extern unsigned int sysctl_vsyscall32;
-extern int force_personality32;
 
 #endif /* !CONFIG_X86_32 */
 
@@ -317,7 +315,9 @@ extern int arch_setup_additional_pages(struct linux_binprm 
*bprm,
 extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
 #define compat_arch_setup_additional_pages     syscall32_setup_pages
 
-extern unsigned long arch_randomize_brk(struct mm_struct *mm);
-#define arch_randomize_brk arch_randomize_brk
+#ifdef CONFIG_X86_32
+#define __HAVE_ARCH_RANDOMIZE_BRK
+extern void randomize_brk(unsigned long old_brk);
+#endif
 
 #endif
diff --git a/include/asm-x86/mmu.h b/include/asm-x86/mmu.h
index efa962c..db9b109 100644
--- a/include/asm-x86/mmu.h
+++ b/include/asm-x86/mmu.h
@@ -9,6 +9,8 @@
  * we put the segment information here.
  *
  * cpu_vm_mask is used to optimize ldt flushing.
+ * exec_limit is used to track the range PROT_EXEC
+ * mappings span.
  */
 typedef struct { 
        void *ldt;
@@ -18,6 +20,10 @@ typedef struct {
        int size;
        struct mutex lock;
        void *vdso;
+#ifdef CONFIG_X86_32
+       struct desc_struct user_cs;
+       unsigned long exec_limit;
+#endif
 } mm_context_t;
 
 #ifdef CONFIG_SMP
diff --git a/include/asm-x86/pgalloc_64.h b/include/asm-x86/pgalloc_64.h
index 8d67223..982e1cb 100644
--- a/include/asm-x86/pgalloc_64.h
+++ b/include/asm-x86/pgalloc_64.h
@@ -5,6 +5,13 @@
 #include <linux/threads.h>
 #include <linux/mm.h>
 
+#define arch_add_exec_range(mm, limit) \
+               do { (void)(mm), (void)(limit); } while (0)
+#define arch_flush_exec_range(mm) \
+               do { (void)(mm); } while (0)
+#define arch_remove_exec_range(mm, limit) \
+               do { (void)(mm), (void)(limit); } while (0)
+
 #define pmd_populate_kernel(mm, pmd, pte) \
                set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte)))
 #define pud_populate(mm, pud, pmd) \
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 149920d..79c8ad8 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -679,6 +679,9 @@ extern int bootloader_type;
 extern char ignore_fpu_irq;
 #define cache_line_size() (boot_cpu_data.x86_cache_alignment)
 
+#define __HAVE_ARCH_ALIGN_STACK
+extern unsigned long arch_align_stack(unsigned long sp);
+
 #define HAVE_ARCH_PICK_MMAP_LAYOUT 1
 #define ARCH_HAS_PREFETCHW
 #define ARCH_HAS_SPINLOCK_PREFETCH
@@ -756,6 +759,9 @@ static inline void prefetchw(const void *x)
        regs->cs = __USER_CS;                                   \
        regs->ip = new_eip;                                     \
        regs->sp = new_esp;                                     \
+       preempt_disable();                                      \
+       load_user_cs_desc(smp_processor_id(), current->mm);     \
+       preempt_enable();                                       \
 } while (0)
 
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e8abb38..1483fc7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1041,7 +1041,13 @@ extern int install_special_mapping(struct mm_struct *mm,
                                   unsigned long addr, unsigned long len,
                                   unsigned long flags, struct page **pages);
 
-extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned 
long, unsigned long, unsigned long);
+extern unsigned long get_unmapped_area_prot(struct file *, unsigned long, 
unsigned long, unsigned long, unsigned long, int);
+
+static inline unsigned long get_unmapped_area(struct file *file, unsigned long 
addr,
+               unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+       return get_unmapped_area_prot(file, addr, len, pgoff, flags, 0);
+}
 
 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
        unsigned long len, unsigned long prot,
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index bfee0bd..30ec32f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -166,6 +166,9 @@ struct mm_struct {
        unsigned long (*get_unmapped_area) (struct file *filp,
                                unsigned long addr, unsigned long len,
                                unsigned long pgoff, unsigned long flags);
+       unsigned long (*get_unmapped_exec_area) (struct file *filp,
+                               unsigned long addr, unsigned long len,
+                               unsigned long pgoff, unsigned long flags);
        void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
        unsigned long mmap_base;                /* base of mmap area */
        unsigned long task_size;                /* size of task vm space */
diff --git a/include/linux/resource.h b/include/linux/resource.h
index ae13db7..14757af 100644
--- a/include/linux/resource.h
+++ b/include/linux/resource.h
@@ -54,8 +54,11 @@ struct rlimit {
 /*
  * Limit the stack by to some sane default: root can always
  * increase this limit if needed..  8MB seems reasonable.
+ *
+ * (2MB more to cover randomization effects.)
  */
-#define _STK_LIM       (8*1024*1024)
+#define _STK_LIM       (10*1024*1024)
+#define EXEC_STACK_BIAS        (2*1024*1024)
 
 /*
  * GPG wants 32kB of mlocked memory, to make sure pass phrases
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 00e1441..c1c8a7d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -98,6 +98,9 @@ struct futex_pi_state;
 struct robust_list_head;
 struct bio;
 
+extern int exec_shield;
+extern int print_fatal_signals;
+
 /*
  * List of flags we want to share for kernel threads,
  * if only because they are not used by them anyway.
@@ -342,6 +345,10 @@ extern int sysctl_max_map_count;
 extern unsigned long
 arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
                       unsigned long, unsigned long);
+
+extern unsigned long
+arch_get_unmapped_exec_area(struct file *, unsigned long, unsigned long,
+                      unsigned long, unsigned long);
 extern unsigned long
 arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
                          unsigned long len, unsigned long pgoff,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d41ef6b..5304704 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -81,6 +81,26 @@ extern int maps_protect;
 extern int sysctl_stat_interval;
 extern int latencytop_enabled;
 
+int exec_shield = (1<<0);
+/* exec_shield is a bitmask:
+ * 0: off; vdso at STACK_TOP, 1 page below TASK_SIZE
+ * (1<<0) 1: on [also on if !=0]
+ * (1<<1) 2: force noexecstack regardless of PT_GNU_STACK
+ * The old settings
+ * (1<<2) 4: vdso just below .text of main (unless too low)
+ * (1<<3) 8: vdso just below .text of PT_INTERP (unless too low)
+ * are ignored because the vdso is placed completely randomly
+ */
+
+static int __init setup_exec_shield(char *str)
+{
+       get_option(&str, &exec_shield);
+
+       return 1;
+}
+
+__setup("exec-shield=", setup_exec_shield);
+
 /* Constants used for minimum and  maximum */
 #if defined(CONFIG_DETECT_SOFTLOCKUP) || defined(CONFIG_HIGHMEM)
 static int one = 1;
@@ -383,6 +403,14 @@ static struct ctl_table kern_table[] = {
                .proc_handler   = &proc_dointvec,
        },
        {
+               .ctl_name       = CTL_UNNUMBERED,
+               .procname       = "exec-shield",
+               .data           = &exec_shield,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec,
+       },
+       {
                .ctl_name       = KERN_CORE_USES_PID,
                .procname       = "core_uses_pid",
                .data           = &core_uses_pid,
diff --git a/mm/mmap.c b/mm/mmap.c
index a32d28c..7634038 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -26,6 +26,7 @@
 #include <linux/mount.h>
 #include <linux/mempolicy.h>
 #include <linux/rmap.h>
+#include <linux/random.h>
 
 #include <asm/uaccess.h>
 #include <asm/cacheflush.h>
@@ -377,6 +378,8 @@ static inline void
 __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
                struct vm_area_struct *prev, struct rb_node *rb_parent)
 {
+       if (vma->vm_flags & VM_EXEC)
+               arch_add_exec_range(mm, vma->vm_end);
        if (prev) {
                vma->vm_next = prev->vm_next;
                prev->vm_next = vma;
@@ -480,6 +483,8 @@ __vma_unlink(struct mm_struct *mm, struct vm_area_struct 
*vma,
        rb_erase(&vma->vm_rb, &mm->mm_rb);
        if (mm->mmap_cache == vma)
                mm->mmap_cache = prev;
+       if (vma->vm_flags & VM_EXEC)
+               arch_remove_exec_range(mm, vma->vm_end);
 }
 
 /*
@@ -785,6 +790,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
                } else                                  /* cases 2, 5, 7 */
                        vma_adjust(prev, prev->vm_start,
                                end, prev->vm_pgoff, NULL);
+               if (prev->vm_flags & VM_EXEC)
+                       arch_add_exec_range(mm, prev->vm_end);
                return prev;
        }
 
@@ -940,7 +947,8 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned 
long addr,
        /* Obtain the address to map to. we verify (or select) it and ensure
         * that it represents a valid section of the address space.
         */
-       addr = get_unmapped_area(file, addr, len, pgoff, flags);
+       addr = get_unmapped_area_prot(file, addr, len, pgoff, flags,
+               prot & PROT_EXEC);
        if (addr & ~PAGE_MASK)
                return addr;
 
@@ -1410,13 +1418,17 @@ void arch_unmap_area_topdown(struct mm_struct *mm, 
unsigned long addr)
 }
 
 unsigned long
-get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
-               unsigned long pgoff, unsigned long flags)
+get_unmapped_area_prot(struct file *file, unsigned long addr, unsigned long 
len,
+               unsigned long pgoff, unsigned long flags, int exec)
 {
        unsigned long (*get_area)(struct file *, unsigned long,
                                  unsigned long, unsigned long, unsigned long);
 
-       get_area = current->mm->get_unmapped_area;
+       if (exec && current->mm->get_unmapped_exec_area)
+               get_area = current->mm->get_unmapped_exec_area;
+       else
+               get_area = current->mm->get_unmapped_area;
+
        if (file && file->f_op && file->f_op->get_unmapped_area)
                get_area = file->f_op->get_unmapped_area;
        addr = get_area(file, addr, len, pgoff, flags);
@@ -1430,8 +1442,75 @@ get_unmapped_area(struct file *file, unsigned long addr, 
unsigned long len,
 
        return arch_rebalance_pgtables(addr, len);
 }
+EXPORT_SYMBOL(get_unmapped_area_prot);
+
+#define SHLIB_BASE             0x00110000
+
+unsigned long arch_get_unmapped_exec_area(struct file *filp, unsigned long 
addr0,
+               unsigned long len0, unsigned long pgoff, unsigned long flags)
+{
+       unsigned long addr = addr0, len = len0;
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+       unsigned long tmp;
+
+       if (len > TASK_SIZE)
+               return -ENOMEM;
+
+       if (flags & MAP_FIXED)
+               return addr;
+
+       if (!addr) {
+               addr = randomize_range(SHLIB_BASE, 0x01000000, len);
+       } else {
+               addr = PAGE_ALIGN(addr);
+               vma = find_vma(mm, addr);
+               if (TASK_SIZE - len >= addr &&
+                   (!vma || addr + len <= vma->vm_start)) {
+                       return addr;
+               }
+       }
+
+       addr = SHLIB_BASE;
+       for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+               /* At this point:  (!vma || addr < vma->vm_end). */
+               if (TASK_SIZE - len < addr)
+                       return -ENOMEM;
+
+               if (!vma || addr + len <= vma->vm_start) {
+                       /*
+                        * Must not let a PROT_EXEC mapping get into the
+                        * brk area:
+                        */
+                       if (addr + len > mm->brk)
+                               goto failed;
+
+                       /*
+                        * Up until the brk area we randomize addresses
+                        * as much as possible:
+                        */
+                       if (addr >= 0x01000000) {
+                               tmp = randomize_range(0x01000000,
+                                       PAGE_ALIGN(max(mm->start_brk,
+                                       (unsigned long)0x08000000)), len);
+                               vma = find_vma(mm, tmp);
+                               if (TASK_SIZE - len >= tmp &&
+                                   (!vma || tmp + len <= vma->vm_start))
+                                       return tmp;
+                       }
+                       /*
+                        * Ok, randomization didnt work out - return
+                        * the result of the linear search:
+                        */
+                       return addr;
+               }
+               addr = vma->vm_end;
+       }
+
+failed:
+       return current->mm->get_unmapped_area(filp, addr0, len0, pgoff, flags);
+}
 
-EXPORT_SYMBOL(get_unmapped_area);
 
 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
 struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
@@ -1506,6 +1585,14 @@ out:
        return prev ? prev->vm_next : vma;
 }
 
+static int over_stack_limit(unsigned long sz)
+{
+       if (sz < EXEC_STACK_BIAS)
+               return 0;
+       return (sz - EXEC_STACK_BIAS) >
+                       current->signal->rlim[RLIMIT_STACK].rlim_cur;
+}
+
 /*
  * Verify that the stack growth is acceptable and
  * update accounting. This is shared with both the
@@ -1522,7 +1609,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, 
unsigned long size, un
                return -ENOMEM;
 
        /* Stack limit test */
-       if (size > rlim[RLIMIT_STACK].rlim_cur)
+       if (over_stack_limit(size))
                return -ENOMEM;
 
        /* mlock limit tests */
@@ -1826,10 +1913,14 @@ int split_vma(struct mm_struct * mm, struct 
vm_area_struct * vma,
        if (new->vm_ops && new->vm_ops->open)
                new->vm_ops->open(new);
 
-       if (new_below)
+       if (new_below) {
+               unsigned long old_end = vma->vm_end;
+
                vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
                        ((addr - new->vm_start) >> PAGE_SHIFT), new);
-       else
+               if (vma->vm_flags & VM_EXEC)
+                       arch_remove_exec_range(mm, old_end);
+       } else
                vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
 
        return 0;
@@ -2048,6 +2139,7 @@ void exit_mmap(struct mm_struct *mm)
        vm_unacct_memory(nr_accounted);
        free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
        tlb_finish_mmu(tlb, 0, end);
+       arch_flush_exec_range(mm);
 
        /*
         * Walk the list again, actually closing and freeing it,
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 4de5468..6d822ad 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -23,8 +23,12 @@
 #include <linux/swapops.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
+#include <asm/pgalloc.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
+#ifdef CONFIG_X86
+#include <asm/desc.h>
+#endif
 
 static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
                unsigned long addr, unsigned long end, pgprot_t newprot,
@@ -134,7 +138,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct 
vm_area_struct **pprev,
        struct mm_struct *mm = vma->vm_mm;
        unsigned long oldflags = vma->vm_flags;
        long nrpages = (end - start) >> PAGE_SHIFT;
-       unsigned long charged = 0;
+       unsigned long charged = 0, old_end = vma->vm_end;
        pgoff_t pgoff;
        int error;
        int dirty_accountable = 0;
@@ -198,6 +202,9 @@ success:
                dirty_accountable = 1;
        }
 
+       if (oldflags & VM_EXEC)
+               arch_remove_exec_range(current->mm, old_end);
+
        if (is_vm_hugetlb_page(vma))
                hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
        else
diff --git a/mm/mremap.c b/mm/mremap.c
index 08e3c7f..101f885 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -392,8 +392,8 @@ unsigned long do_mremap(unsigned long addr,
                        if (vma->vm_flags & VM_MAYSHARE)
                                map_flags |= MAP_SHARED;
 
-                       new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
-                                               vma->vm_pgoff, map_flags);
+                       new_addr = get_unmapped_area_prot(vma->vm_file, 0, 
new_len,
+                               vma->vm_pgoff, map_flags, vma->vm_flags & 
VM_EXEC);
                        if (new_addr & ~PAGE_MASK) {
                                ret = new_addr;
                                goto out;
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