vm audit: add VM_DONTEXPAND to mmap for drivers that need it
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>
diff --git a/sound/oss/via82cxxx_audio.c b/sound/oss/via82cxxx_audio.c
index 5d3c037..f95aa09 100644
--- a/sound/oss/via82cxxx_audio.c
+++ b/sound/oss/via82cxxx_audio.c
@@ -2104,6 +2104,7 @@
{
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 @@
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 */
diff --git a/sound/usb/usx2y/usX2Yhwdep.c b/sound/usb/usx2y/usX2Yhwdep.c
index 6495534e..1558a5c 100644
--- a/sound/usb/usx2y/usX2Yhwdep.c
+++ b/sound/usb/usx2y/usX2Yhwdep.c
@@ -84,7 +84,7 @@
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;
}
diff --git a/sound/usb/usx2y/usx2yhwdeppcm.c b/sound/usb/usx2y/usx2yhwdeppcm.c
index 800b5ce..117946f 100644
--- a/sound/usb/usx2y/usx2yhwdeppcm.c
+++ b/sound/usb/usx2y/usx2yhwdeppcm.c
@@ -722,7 +722,7 @@
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;
}