Commit ef388e20 authored Dec 05, 2016 by Darrick J. Wong Committed by Dave Chinner Dec 05, 2016

xfs: don't allow di_size with high bit set



The on-disk field di_size is used to set i_size, which is a signed
integer of loff_t.  If the high bit of di_size is set, we'll end up with
a negative i_size, which will cause all sorts of problems.  Since the
VFS won't let us create a file with such length, we should catch them
here in the verifier too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

parent 0f352f8e

fs/xfs/libxfs/xfs_inode_buf.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -392,6 +392,14 @@ xfs_dinode_verify(
		if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
		return false;

		/* don't allow invalid i_size */
		if (be64_to_cpu(dip->di_size) & (1ULL << 63))
		return false;

		/* No zero-length symlinks. */
		if (S_ISLNK(be16_to_cpu(dip->di_mode)) && dip->di_size == 0)
		return false;

		/* only version 3 or greater inodes are extensively verified here */
		if (dip->di_version < 3)
		return true;

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