[Qemu-devel] [PATCH 2/2] linux-user: Correct type for BLKSSZGET

[Peter Maydell]

The BLKSSZGET ioctl takes an argument which is a pointer to an int.
We were incorrectly declaring it to take a pointer to a long, which
meant that we would incorrectly write to memory which we should not
if the guest is a 64-bit architecture.

In particular, kpartx uses this ioctl to write to an int on the
stack, which tends to result in it crashing immediately.

Reported-by: Chanho Park <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>
---
 linux-user/ioctls.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
index 72cd32a..8978eb3 100644
--- a/linux-user/ioctls.h
+++ b/linux-user/ioctls.h
@@ -76,7 +76,7 @@
      IOCTL(BLKFLSBUF, 0, TYPE_NULL)
      IOCTL(BLKRASET, 0, TYPE_INT)
      IOCTL(BLKRAGET, IOC_R, MK_PTR(TYPE_LONG))
-     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_LONG))
+     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_INT))
      IOCTL(BLKBSZGET, IOC_R, MK_PTR(TYPE_INT))
      IOCTL_SPECIAL(BLKPG, IOC_W, do_ioctl_blkpg,
                    MK_PTR(MK_STRUCT(STRUCT_blkpg_ioctl_arg)))
-- 
1.9.1