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

Greg KH
2008-02-07T20:52:16Z

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

------------------
From: Nick Piggin <npiggin@suse.de>

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@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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;
}

--