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SubjectRe: sparc: Fix mremap VA span checking.
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From: Martin Habets <errandir_news@mph.eclipse.co.uk>
Date: Tue, 13 May 2008 00:12:32 +0100

> On Mon, May 12, 2008 at 04:24:53AM -0700, David Miller wrote:
> > From: Jan Lieskovsky <jlieskov@redhat.com>
> > Date: Mon, 12 May 2008 13:15:12 +0200
> >
> > > I have investigated the code for MREMAP_FIXED in
> > > sparc_mremap in arch/sparc/kernel/sys_sparc.c, for sys64_mremap
> > > in arch/sparc64/kernel/sys_sparc.c and
> > > for sys32_mremap in arch/sparc64/kernel/sys_sparc32.c
> > > and there are similar conditional range checks ->
> > > attaching the patches against 2.6.25.3.
> >
> > Thanks for the report, I'll take a look at this after getting
> > some sleep as it's late hear.
> >
> > My first impression is that it might make sense to put an
> > arch_mmap_check() call at the appropriate spots instead of duplicating
> > this check so many times.
>
> sparc32 already has an sparc_mmap_check() in sys_sparc that does this,
> and sparc64 has sparc64_mmap_check().
> Calling that should do the trick.

Right, I was just about to test the following patch:

diff --git a/arch/sparc/kernel/sys_sparc.c b/arch/sparc/kernel/sys_sparc.c
index e995491..3c6b49a 100644
--- a/arch/sparc/kernel/sys_sparc.c
+++ b/arch/sparc/kernel/sys_sparc.c
@@ -219,7 +219,7 @@ out:
return err;
}

-int sparc_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
+int sparc_mmap_check(unsigned long addr, unsigned long len)
{
if (ARCH_SUN4C_SUN4 &&
(len > 0x20000000 ||
@@ -295,52 +295,14 @@ asmlinkage unsigned long sparc_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
- struct vm_area_struct *vma;
unsigned long ret = -EINVAL;
- if (ARCH_SUN4C_SUN4) {
- if (old_len > 0x20000000 || new_len > 0x20000000)
- goto out;
- if (addr < 0xe0000000 && addr + old_len > 0x20000000)
- goto out;
- }
- if (old_len > TASK_SIZE - PAGE_SIZE ||
- new_len > TASK_SIZE - PAGE_SIZE)
+
+ if (unlikely(sparc_mmap_check(addr, old_len)))
+ goto out;
+ if (unlikely(sparc_mmap_check(new_addr, new_len)))
goto out;
down_write(&current->mm->mmap_sem);
- if (flags & MREMAP_FIXED) {
- if (ARCH_SUN4C_SUN4 &&
- new_addr < 0xe0000000 &&
- new_addr + new_len > 0x20000000)
- goto out_sem;
- if (new_addr + new_len > TASK_SIZE - PAGE_SIZE)
- goto out_sem;
- } else if ((ARCH_SUN4C_SUN4 && addr < 0xe0000000 &&
- addr + new_len > 0x20000000) ||
- addr + new_len > TASK_SIZE - PAGE_SIZE) {
- unsigned long map_flags = 0;
- struct file *file = NULL;
-
- ret = -ENOMEM;
- if (!(flags & MREMAP_MAYMOVE))
- goto out_sem;
-
- vma = find_vma(current->mm, addr);
- if (vma) {
- if (vma->vm_flags & VM_SHARED)
- map_flags |= MAP_SHARED;
- file = vma->vm_file;
- }
-
- new_addr = get_unmapped_area(file, addr, new_len,
- vma ? vma->vm_pgoff : 0,
- map_flags);
- ret = new_addr;
- if (new_addr & ~PAGE_MASK)
- goto out_sem;
- flags |= MREMAP_FIXED;
- }
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
-out_sem:
up_write(&current->mm->mmap_sem);
out:
return ret;
diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c
index 0dbc941..ac1bff5 100644
--- a/arch/sparc64/kernel/sys_sparc.c
+++ b/arch/sparc64/kernel/sys_sparc.c
@@ -542,8 +542,7 @@ asmlinkage long sparc64_personality(unsigned long personality)
return ret;
}

-int sparc64_mmap_check(unsigned long addr, unsigned long len,
- unsigned long flags)
+int sparc64_mmap_check(unsigned long addr, unsigned long len)
{
if (test_thread_flag(TIF_32BIT)) {
if (len >= STACK_TOP32)
@@ -609,46 +608,19 @@ asmlinkage unsigned long sys64_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
- struct vm_area_struct *vma;
unsigned long ret = -EINVAL;

if (test_thread_flag(TIF_32BIT))
goto out;
if (unlikely(new_len >= VA_EXCLUDE_START))
goto out;
- if (unlikely(invalid_64bit_range(addr, old_len)))
+ if (unlikely(sparc64_mmap_check(addr, old_len)))
+ goto out;
+ if (unlikely(sparc64_mmap_check(new_addr, new_len)))
goto out;

down_write(&current->mm->mmap_sem);
- if (flags & MREMAP_FIXED) {
- if (invalid_64bit_range(new_addr, new_len))
- goto out_sem;
- } else if (invalid_64bit_range(addr, new_len)) {
- unsigned long map_flags = 0;
- struct file *file = NULL;
-
- ret = -ENOMEM;
- if (!(flags & MREMAP_MAYMOVE))
- goto out_sem;
-
- vma = find_vma(current->mm, addr);
- if (vma) {
- if (vma->vm_flags & VM_SHARED)
- map_flags |= MAP_SHARED;
- file = vma->vm_file;
- }
-
- /* MREMAP_FIXED checked above. */
- new_addr = get_unmapped_area(file, addr, new_len,
- vma ? vma->vm_pgoff : 0,
- map_flags);
- ret = new_addr;
- if (new_addr & ~PAGE_MASK)
- goto out_sem;
- flags |= MREMAP_FIXED;
- }
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
-out_sem:
up_write(&current->mm->mmap_sem);
out:
return ret;
diff --git a/arch/sparc64/kernel/sys_sparc32.c b/arch/sparc64/kernel/sys_sparc32.c
index 1aa4288..ba5bd62 100644
--- a/arch/sparc64/kernel/sys_sparc32.c
+++ b/arch/sparc64/kernel/sys_sparc32.c
@@ -867,44 +867,15 @@ asmlinkage unsigned long sys32_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, u32 __new_addr)
{
- struct vm_area_struct *vma;
unsigned long ret = -EINVAL;
unsigned long new_addr = __new_addr;

- if (old_len > STACK_TOP32 || new_len > STACK_TOP32)
+ if (unlikely(sparc64_mmap_check(addr, old_len)))
goto out;
- if (addr > STACK_TOP32 - old_len)
+ if (unlikely(sparc64_mmap_check(new_addr, new_len)))
goto out;
down_write(&current->mm->mmap_sem);
- if (flags & MREMAP_FIXED) {
- if (new_addr > STACK_TOP32 - new_len)
- goto out_sem;
- } else if (addr > STACK_TOP32 - new_len) {
- unsigned long map_flags = 0;
- struct file *file = NULL;
-
- ret = -ENOMEM;
- if (!(flags & MREMAP_MAYMOVE))
- goto out_sem;
-
- vma = find_vma(current->mm, addr);
- if (vma) {
- if (vma->vm_flags & VM_SHARED)
- map_flags |= MAP_SHARED;
- file = vma->vm_file;
- }
-
- /* MREMAP_FIXED checked above. */
- new_addr = get_unmapped_area(file, addr, new_len,
- vma ? vma->vm_pgoff : 0,
- map_flags);
- ret = new_addr;
- if (new_addr & ~PAGE_MASK)
- goto out_sem;
- flags |= MREMAP_FIXED;
- }
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
-out_sem:
up_write(&current->mm->mmap_sem);
out:
return ret;
diff --git a/include/asm-sparc/mman.h b/include/asm-sparc/mman.h
index e18be98..3d16b40 100644
--- a/include/asm-sparc/mman.h
+++ b/include/asm-sparc/mman.h
@@ -24,9 +24,8 @@

#ifdef __KERNEL__
#ifndef __ASSEMBLY__
-#define arch_mmap_check sparc_mmap_check
-int sparc_mmap_check(unsigned long addr, unsigned long len,
- unsigned long flags);
+#define arch_mmap_check(addr,len,flags) sparc_mmap_check(addr,len)
+int sparc_mmap_check(unsigned long addr, unsigned long len);
#endif
#endif

diff --git a/include/asm-sparc64/mman.h b/include/asm-sparc64/mman.h
index e584563..625be4d 100644
--- a/include/asm-sparc64/mman.h
+++ b/include/asm-sparc64/mman.h
@@ -24,9 +24,8 @@

#ifdef __KERNEL__
#ifndef __ASSEMBLY__
-#define arch_mmap_check sparc64_mmap_check
-int sparc64_mmap_check(unsigned long addr, unsigned long len,
- unsigned long flags);
+#define arch_mmap_check(addr,len,flags) sparc64_mmap_check(addr,len)
+int sparc64_mmap_check(unsigned long addr, unsigned long len);
#endif
#endif


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