[NET] compat ifconf: fix limits
A recent change to compat. dev_ifconf() in fs/compat_ioctl.c
causes ifconf data to be truncated 1 entry too early when copying it
to userspace. The correct amount of data (length) is returned,
but the final entry is empty (zero, not filled in).
The for-loop 'i' check should use <= to allow the final struct
ifreq32 to be copied. I also used the ifconf-corruption program
in kernel bugzilla #4746 to make sure that this change does not
re-introduce the corruption.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 537ac70..c666769 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -446,7 +446,7 @@
ifr = ifc.ifc_req;
ifr32 = compat_ptr(ifc32.ifcbuf);
for (i = 0, j = 0;
- i + sizeof (struct ifreq32) < ifc32.ifc_len && j < ifc.ifc_len;
+ i + sizeof (struct ifreq32) <= ifc32.ifc_len && j < ifc.ifc_len;
i += sizeof (struct ifreq32), j += sizeof (struct ifreq)) {
if (copy_in_user(ifr32, ifr, sizeof (struct ifreq32)))
return -EFAULT;