Commit 1efa3c05 authored Mar 08, 2006 by Randy Dunlap Committed by David S. Miller Mar 08, 2006

[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>

parent 2ec5e3a8

fs/compat_ioctl.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -446,7 +446,7 @@ static int dev_ifconf(unsigned int fd, unsigned int cmd, unsigned long arg)
		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;

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