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SubjectRe: IA64 non-contiguous memory space bugs
On Wed, Feb 22, 2006 at 08:19:51AM -0800, Chen, Kenneth W wrote:
> David Gibson wrote on Tuesday, February 21, 2006 4:14 PM
> > --- working-2.6.orig/include/linux/mm.h 2004-09-07 10:38:00.000000000 +1000
> > +++ working-2.6/include/linux/mm.h 2004-09-24 15:02:18.172776168 +1000
> > @@ -41,6 +41,13 @@
> > #define MM_VM_SIZE(mm) TASK_SIZE
> > #endif
> >
> > +#ifndef REGION_MAX
> > +#define REGION_MAX(addr) TASK_SIZE
> > +#endif
> > +
> > +#define GOOD_TASK_VM_RANGE(addr, len) \
> > + ( ((addr)+(len) >= (addr)) || ((addr)+(len) <= TASK_SIZE) \
> > + || ((addr)+(len) <= REGION_MAX(addr)) )
>
> Looks like the logic is reversed, should be && instead of ||.

Ah, yes indeed. Looks like I screwed up my de Morgan's when I changed
it from BAD_TASK_VM_RANGE(). This and another reject fixed in the
version below. Mind you it's been a long time since I wrote this, so
it should probably be checked for any new places where the tests need
to be changed. I'm probably not the best person to do that, since I
don't have an ia64 machine to test on.

Index: working-2.6/mm/mremap.c
===================================================================
--- working-2.6.orig/mm/mremap.c 2006-01-16 13:02:29.000000000 +1100
+++ working-2.6/mm/mremap.c 2006-02-23 09:54:52.000000000 +1100
@@ -278,7 +278,7 @@ unsigned long do_mremap(unsigned long ad
if (!(flags & MREMAP_MAYMOVE))
goto out;

- if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
+ if (! GOOD_TASK_VM_RANGE(new_addr, new_len))
goto out;

/* Check if the location we're moving into overlaps the
@@ -355,6 +355,8 @@ unsigned long do_mremap(unsigned long ad
!((flags & MREMAP_FIXED) && (addr != new_addr)) &&
(old_len != new_len || !(flags & MREMAP_MAYMOVE))) {
unsigned long max_addr = TASK_SIZE;
+ if (max_addr > REGION_MAX(vma->vm_start))
+ max_addr = REGION_MAX(vma->vm_start);
if (vma->vm_next)
max_addr = vma->vm_next->vm_start;
/* can we just expand the current mapping? */
Index: working-2.6/mm/mmap.c
===================================================================
--- working-2.6.orig/mm/mmap.c 2006-02-23 09:54:43.000000000 +1100
+++ working-2.6/mm/mmap.c 2006-02-23 10:00:08.000000000 +1100
@@ -1345,7 +1345,7 @@ get_unmapped_area(struct file *file, uns
return addr;
}

- if (addr > TASK_SIZE - len)
+ if (! GOOD_TASK_VM_RANGE(addr, len))
return -ENOMEM;
if (addr & ~PAGE_MASK)
return -EINVAL;
@@ -1757,7 +1757,7 @@ int do_munmap(struct mm_struct *mm, unsi
unsigned long end;
struct vm_area_struct *vma, *prev, *last;

- if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
+ if ((start & ~PAGE_MASK) || !GOOD_TASK_VM_RANGE(start, len))
return -EINVAL;

if ((len = PAGE_ALIGN(len)) == 0)
@@ -1851,7 +1851,7 @@ unsigned long do_brk(unsigned long addr,
if (!len)
return addr;

- if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+ if (! GOOD_TASK_VM_RANGE(addr, len))
return -EINVAL;

/*
Index: working-2.6/include/asm-ia64/page.h
===================================================================
--- working-2.6.orig/include/asm-ia64/page.h 2006-01-16 13:02:29.000000000 +1100
+++ working-2.6/include/asm-ia64/page.h 2006-02-23 09:54:52.000000000 +1100
@@ -142,6 +142,8 @@ typedef union ia64_va {
#define REGION_NUMBER(x) ({ia64_va _v; _v.l = (long) (x); _v.f.reg;})
#define REGION_OFFSET(x) ({ia64_va _v; _v.l = (long) (x); _v.f.off;})

+#define REGION_MAX(x) ((REGION_NUMBER(x)<<61) + RGN_MAP_LIMIT)
+
#ifdef CONFIG_HUGETLB_PAGE
# define htlbpage_to_page(x) (((unsigned long) REGION_NUMBER(x) << 61) \
| (REGION_OFFSET(x) >> (HPAGE_SHIFT-PAGE_SHIFT)))
Index: working-2.6/include/linux/mm.h
===================================================================
--- working-2.6.orig/include/linux/mm.h 2006-02-20 10:55:12.000000000 +1100
+++ working-2.6/include/linux/mm.h 2006-02-23 10:01:51.000000000 +1100
@@ -41,6 +41,13 @@ extern int sysctl_legacy_va_layout;

#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))

+#ifndef REGION_MAX
+#define REGION_MAX(addr) TASK_SIZE
+#endif
+
+#define GOOD_TASK_VM_RANGE(addr, len) \
+ ( ((addr)+(len) >= (addr)) && ((addr)+(len) <= TASK_SIZE) \
+ && ((addr)+(len) <= REGION_MAX(addr)) )
/*
* Linux kernel virtual memory manager primitives.
* The idea being to have a "virtual" mm in the same way
Index: working-2.6/fs/binfmt_elf.c
===================================================================
--- working-2.6.orig/fs/binfmt_elf.c 2006-01-16 13:08:42.000000000 +1100
+++ working-2.6/fs/binfmt_elf.c 2006-02-23 09:54:52.000000000 +1100
@@ -86,7 +86,8 @@ static struct linux_binfmt elf_format =
.min_coredump = ELF_EXEC_PAGESIZE
};

-#define BAD_ADDR(x) ((unsigned long)(x) > TASK_SIZE)
+#define BAD_ADDR(x) (((unsigned long)(x) > TASK_SIZE) \
+ || ((unsigned long)(x) >= REGION_MAX((unsigned long)x)) )

static int set_brk(unsigned long start, unsigned long end)
{
@@ -389,8 +390,8 @@ static unsigned long load_elf_interp(str
* <= p_memsize so it is only necessary to check p_memsz.
*/
k = load_addr + eppnt->p_vaddr;
- if (k > TASK_SIZE || eppnt->p_filesz > eppnt->p_memsz ||
- eppnt->p_memsz > TASK_SIZE || TASK_SIZE - eppnt->p_memsz < k) {
+ if ((eppnt->p_filesz > eppnt->p_memsz) ||
+ ! GOOD_TASK_VM_RANGE(k, eppnt->p_memsz)) {
error = -ENOMEM;
goto out_close;
}
@@ -871,9 +872,8 @@ static int load_elf_binary(struct linux_
* allowed task size. Note that p_filesz must always be
* <= p_memsz so it is only necessary to check p_memsz.
*/
- if (k > TASK_SIZE || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
- elf_ppnt->p_memsz > TASK_SIZE ||
- TASK_SIZE - elf_ppnt->p_memsz < k) {
+ if (elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
+ ! GOOD_TASK_VM_RANGE(k, elf_ppnt->p_memsz)) {
/* set_brk can never work. Avoid overflows. */
send_sig(SIGKILL, current, 0);
goto out_free_dentry;
Index: working-2.6/arch/ia64/kernel/sys_ia64.c
===================================================================
--- working-2.6.orig/arch/ia64/kernel/sys_ia64.c 2006-01-16 13:02:16.000000000 +1100
+++ working-2.6/arch/ia64/kernel/sys_ia64.c 2006-02-23 09:54:52.000000000 +1100
@@ -189,17 +189,6 @@ do_mmap2 (unsigned long addr, unsigned l
goto out;
}

- /*
- * Don't permit mappings into unmapped space, the virtual page table of a region,
- * or across a region boundary. Note: RGN_MAP_LIMIT is equal to 2^n-PAGE_SIZE
- * (for some integer n <= 61) and len > 0.
- */
- roff = REGION_OFFSET(addr);
- if ((len > RGN_MAP_LIMIT) || (roff > (RGN_MAP_LIMIT - len))) {
- addr = -EINVAL;
- goto out;
- }
-
down_write(&current->mm->mmap_sem);
addr = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
up_write(&current->mm->mmap_sem);

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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