[patch 03/45] vm audit: add VM_DONTEXPAND to mmap for drivers thatneed it (CVE-2008-0007)

[Greg KH]

2.6.24-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Nick Piggin <npiggin@xxxxxxx>

Drivers that register a ->fault handler, but do not range-check the
offset argument, must set VM_DONTEXPAND in the vm_flags in order to
prevent an expanding mremap from overflowing the resource.

I've audited the tree and attempted to fix these problems (usually by
adding VM_DONTEXPAND where it is not obvious).

Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/char/drm/drm_vm.c       |    2 ++
 drivers/char/mspec.c            |    2 +-
 fs/ncpfs/mmap.c                 |    4 ----
 kernel/relay.c                  |    1 +
 mm/mmap.c                       |    2 +-
 sound/oss/via82cxxx_audio.c     |   14 ++++++--------
 sound/usb/usx2y/usX2Yhwdep.c    |    2 +-
 sound/usb/usx2y/usx2yhwdeppcm.c |    2 +-
 8 files changed, 13 insertions(+), 16 deletions(-)

--- a/drivers/char/drm/drm_vm.c
+++ b/drivers/char/drm/drm_vm.c
@@ -506,6 +506,7 @@ static int drm_mmap_dma(struct file *fil
 	vma->vm_ops = &drm_vm_dma_ops;
 
 	vma->vm_flags |= VM_RESERVED;	/* Don't swap */
+	vma->vm_flags |= VM_DONTEXPAND;
 
 	vma->vm_file = filp;	/* Needed for drm_vm_open() */
 	drm_vm_open_locked(vma);
@@ -655,6 +656,7 @@ static int drm_mmap_locked(struct file *
 		return -EINVAL;	/* This should never happen. */
 	}
 	vma->vm_flags |= VM_RESERVED;	/* Don't swap */
+	vma->vm_flags |= VM_DONTEXPAND;
 
 	vma->vm_file = filp;	/* Needed for drm_vm_open() */
 	drm_vm_open_locked(vma);
--- a/drivers/char/mspec.c
+++ b/drivers/char/mspec.c
@@ -283,7 +283,7 @@ mspec_mmap(struct file *file, struct vm_
 	vdata->refcnt = ATOMIC_INIT(1);
 	vma->vm_private_data = vdata;
 
-	vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP);
+	vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP | VM_DONTEXPAND);
 	if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
 		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	vma->vm_ops = &mspec_vm_ops;
--- a/fs/ncpfs/mmap.c
+++ b/fs/ncpfs/mmap.c
@@ -50,10 +50,6 @@ static int ncp_file_mmap_fault(struct vm
 	pos = vmf->pgoff << PAGE_SHIFT;
 
 	count = PAGE_SIZE;
-	if ((unsigned long)vmf->virtual_address + PAGE_SIZE > area->vm_end) {
-		WARN_ON(1); /* shouldn't happen? */
-		count = area->vm_end - (unsigned long)vmf->virtual_address;
-	}
 	/* what we can read in one go */
 	bufsize = NCP_SERVER(inode)->buffer_size;
 
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -92,6 +92,7 @@ static int relay_mmap_buf(struct rchan_b
 		return -EINVAL;
 
 	vma->vm_ops = &relay_file_mmap_ops;
+	vma->vm_flags |= VM_DONTEXPAND;
 	vma->vm_private_data = buf;
 	buf->chan->cb->buf_mapped(buf, filp);
 
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2215,7 +2215,7 @@ int install_special_mapping(struct mm_st
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 
-	vma->vm_flags = vm_flags | mm->def_flags;
+	vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 
 	vma->vm_ops = &special_mapping_vmops;
--- a/sound/oss/via82cxxx_audio.c
+++ b/sound/oss/via82cxxx_audio.c
@@ -2104,6 +2104,7 @@ static struct page * via_mm_nopage (stru
 {
 	struct via_info *card = vma->vm_private_data;
 	struct via_channel *chan = &card->ch_out;
+	unsigned long max_bufs;
 	struct page *dmapage;
 	unsigned long pgoff;
 	int rd, wr;
@@ -2127,14 +2128,11 @@ static struct page * via_mm_nopage (stru
 	rd = card->ch_in.is_mapped;
 	wr = card->ch_out.is_mapped;
 
-#ifndef VIA_NDEBUG
-	{
-	unsigned long max_bufs = chan->frag_number;
-	if (rd && wr) max_bufs *= 2;
-	/* via_dsp_mmap() should ensure this */
-	assert (pgoff < max_bufs);
-	}
-#endif
+	max_bufs = chan->frag_number;
+	if (rd && wr)
+		max_bufs *= 2;
+	if (pgoff >= max_bufs)
+		return NOPAGE_SIGBUS;
 
 	/* if full-duplex (read+write) and we have two sets of bufs,
 	 * then the playback buffers come first, sez soundcard.c */
--- a/sound/usb/usx2y/usX2Yhwdep.c
+++ b/sound/usb/usx2y/usX2Yhwdep.c
@@ -88,7 +88,7 @@ static int snd_us428ctls_mmap(struct snd
 		us428->us428ctls_sharedmem->CtlSnapShotLast = -2;
 	}
 	area->vm_ops = &us428ctls_vm_ops;
-	area->vm_flags |= VM_RESERVED;
+	area->vm_flags |= VM_RESERVED | VM_DONTEXPAND;
 	area->vm_private_data = hw->private_data;
 	return 0;
 }
--- a/sound/usb/usx2y/usx2yhwdeppcm.c
+++ b/sound/usb/usx2y/usx2yhwdeppcm.c
@@ -728,7 +728,7 @@ static int snd_usX2Y_hwdep_pcm_mmap(stru
 		return -ENODEV;
 	}
 	area->vm_ops = &snd_usX2Y_hwdep_pcm_vm_ops;
-	area->vm_flags |= VM_RESERVED;
+	area->vm_flags |= VM_RESERVED | VM_DONTEXPAND;
 	area->vm_private_data = hw->private_data;
 	return 0;
 }

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/