Commit 75067034 authored Jul 23, 2019 by Luis Henriques Committed by Ilya Dryomov Sep 16, 2019

ceph: fix directories inode i_blkbits initialization



When filling an inode with info from the MDS, i_blkbits is being
initialized using fl_stripe_unit, which contains the stripe unit in
bytes.  Unfortunately, this doesn't make sense for directories as they
have fl_stripe_unit set to '0'.  This means that i_blkbits will be set
to 0xff, causing an UBSAN undefined behaviour in i_blocksize():

  UBSAN: Undefined behaviour in ./include/linux/fs.h:731:12
  shift exponent 255 is too large for 32-bit type 'int'

Fix this by initializing i_blkbits to CEPH_BLOCK_SHIFT if fl_stripe_unit
is zero.

Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

parent 4d856f72

fs/ceph/inode.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -801,7 +801,12 @@ static int fill_inode(struct inode inode, struct page locked_page,

		/* update inode */
		inode->i_rdev = le32_to_cpu(info->rdev);
		inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
		/* directories have fl_stripe_unit set to zero */
		if (le32_to_cpu(info->layout.fl_stripe_unit))
		inode->i_blkbits =
		fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
		else
		inode->i_blkbits = CEPH_BLOCK_SHIFT;

		__ceph_update_quota(ci, iinfo->max_bytes, iinfo->max_files);

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