xfs: fix a null pointer dereference in xfs_bmap_extents_to_btree

Fuzzing tool reports a write to null pointer error in the
xfs_bmap_extents_to_btree, fix it by bailing out on encountering
a null pointer.

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Shan Hai 2018-08-10 17:55:55 -07:00 committed by Darrick J. Wong
parent fa6c668d80
commit 01239d77b9

View File

@ -712,19 +712,14 @@ xfs_bmap_extents_to_btree(
args.wasdel = wasdel;
*logflagsp = 0;
if ((error = xfs_alloc_vextent(&args))) {
xfs_iroot_realloc(ip, -1, whichfork);
ASSERT(ifp->if_broot == NULL);
XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
return error;
goto err1;
}
if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
xfs_iroot_realloc(ip, -1, whichfork);
ASSERT(ifp->if_broot == NULL);
XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
return -ENOSPC;
error = -ENOSPC;
goto err1;
}
/*
* Allocation can't fail, the space was reserved.
@ -736,6 +731,10 @@ xfs_bmap_extents_to_btree(
ip->i_d.di_nblocks++;
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
abp = xfs_btree_get_bufl(mp, tp, args.fsbno, 0);
if (!abp) {
error = -ENOSPC;
goto err2;
}
/*
* Fill in the child block.
*/
@ -775,6 +774,15 @@ xfs_bmap_extents_to_btree(
*curp = cur;
*logflagsp = XFS_ILOG_CORE | xfs_ilog_fbroot(whichfork);
return 0;
err2:
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
err1:
xfs_iroot_realloc(ip, -1, whichfork);
XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
return error;
}
/*