vm audit: add VM_DONTEXPAND to mmap for drivers that need it
Nick Piggin [Sat, 2 Feb 2008 02:08:53 +0000 (03:08 +0100)]
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>

drivers/char/drm/drm_vm.c
drivers/char/mspec.c
fs/ncpfs/mmap.c
kernel/relay.c
mm/mmap.c
sound/oss/via82cxxx_audio.c
sound/usb/usx2y/usX2Yhwdep.c
sound/usb/usx2y/usx2yhwdeppcm.c

index e8d50af..ef5e6b1 100644 (file)
@@ -506,6 +506,7 @@ static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma)
        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 *filp, struct vm_area_struct *vma)
                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);
index 82f2e27..ff146c2 100644 (file)
@@ -283,7 +283,7 @@ mspec_mmap(struct file *file, struct vm_area_struct *vma,
        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;
index a94473d..5d8dcb9 100644 (file)
@@ -50,10 +50,6 @@ static int ncp_file_mmap_fault(struct vm_area_struct *area,
        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;
 
index 61134eb..7c03733 100644 (file)
@@ -92,6 +92,7 @@ static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
                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);
 
index d2b6d44..8295577 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2216,7 +2216,7 @@ int install_special_mapping(struct mm_struct *mm,
        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;
index 5d3c037..f95aa09 100644 (file)
@@ -2104,6 +2104,7 @@ static struct page * via_mm_nopage (struct vm_area_struct * vma,
 {
        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 (struct vm_area_struct * vma,
        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 */
index 6495534..1558a5c 100644 (file)
@@ -84,7 +84,7 @@ static int snd_us428ctls_mmap(struct snd_hwdep * hw, struct file *filp, struct v
                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;
 }
index 800b5ce..117946f 100644 (file)
@@ -722,7 +722,7 @@ static int snd_usX2Y_hwdep_pcm_mmap(struct snd_hwdep * hw, struct file *filp, st
                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;
 }