1 files changed, 49 insertions, 43 deletions

diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index 399ff49..01d8db1 100644
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -9,6 +9,7 @@
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/stringify.h>
+#include <linux/security.h>
 #include <asm/proto.h>
 #include <asm/tlbflush.h>
 #include <asm/ia32_unistd.h>
@@ -30,51 +31,57 @@ extern int sysctl_vsyscall32;
 char *syscall32_page; 
 static int use_sysenter = -1;
 
-/*
- * Map the 32bit vsyscall page on demand.
- *
- * RED-PEN: This knows too much about high level VM.
- *
- * Alternative would be to generate a vma with appropriate backing options
- * and let it be handled by generic VM.
- */
-int __map_syscall32(struct mm_struct *mm, unsigned long address)
-{ 
-	pgd_t *pgd;
-	pud_t *pud;
-	pte_t *pte;
-	pmd_t *pmd;
-	int err = -ENOMEM;
-
-	spin_lock(&mm->page_table_lock); 
- 	pgd = pgd_offset(mm, address);
- 	pud = pud_alloc(mm, pgd, address);
- 	if (pud) {
- 		pmd = pmd_alloc(mm, pud, address);
- 		if (pmd && (pte = pte_alloc_map(mm, pmd, address)) != NULL) {
- 			if (pte_none(*pte)) {
- 				set_pte(pte,
- 					mk_pte(virt_to_page(syscall32_page),
- 					       PAGE_KERNEL_VSYSCALL32));
- 			}
- 			/* Flush only the local CPU. Other CPUs taking a fault
- 			   will just end up here again
-			   This probably not needed and just paranoia. */
- 			__flush_tlb_one(address);
- 			err = 0;
-		}
-	}
-	spin_unlock(&mm->page_table_lock);
-	return err;
+static struct page *
+syscall32_nopage(struct vm_area_struct *vma, unsigned long adr, int *type)
+{
+	struct page *p = virt_to_page(adr - vma->vm_start + syscall32_page);
+	get_page(p);
+	return p;
 }
 
-int map_syscall32(struct mm_struct *mm, unsigned long address)
+/* Prevent VMA merging */
+static void syscall32_vma_close(struct vm_area_struct *vma)
 {
-	int err;
-	down_read(&mm->mmap_sem);
-	err = __map_syscall32(mm, address);
-	up_read(&mm->mmap_sem);
-	return err;
+}
+
+static struct vm_operations_struct syscall32_vm_ops = {
+	.close = syscall32_vma_close,
+	.nopage = syscall32_nopage,
+};
+
+struct linux_binprm;
+
+/* Setup a VMA at program startup for the vsyscall page */
+int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
+{
+	int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+
+	vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+	if (!vma)
+		return -ENOMEM;
+	if (security_vm_enough_memory(npages)) {
+		kmem_cache_free(vm_area_cachep, vma);
+		return -ENOMEM;
+	}
+
+	memset(vma, 0, sizeof(struct vm_area_struct));
+	/* Could randomize here */
+	vma->vm_start = VSYSCALL32_BASE;
+	vma->vm_end = VSYSCALL32_END;
+	/* MAYWRITE to allow gdb to COW and set breakpoints */
+	vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYEXEC|VM_MAYWRITE;
+	vma->vm_flags |= mm->def_flags;
+	vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+	vma->vm_ops = &syscall32_vm_ops;
+	vma->vm_mm = mm;
+
+	down_write(&mm->mmap_sem);
+	insert_vm_struct(mm, vma);
+	mm->total_vm += npages;
+	up_write(&mm->mmap_sem);
+	return 0;
 }
 
 static int __init init_syscall32(void)
@@ -82,7 +89,6 @@ static int __init init_syscall32(void)
 	syscall32_page = (void *)get_zeroed_page(GFP_KERNEL); 
 	if (!syscall32_page) 
 		panic("Cannot allocate syscall32 page"); 
-	SetPageReserved(virt_to_page(syscall32_page));
  	if (use_sysenter > 0) {
  		memcpy(syscall32_page, syscall32_sysenter,
  		       syscall32_sysenter_end - syscall32_sysenter);