xfs: filter out obviously bad btree pointers

commit d5a91baeb6033c3392121e4d5c011cdc08dfa9f7 upstream.

Don't let anybody load an obviously bad btree pointer.  Since the values
come from disk, we must return an error, not just ASSERT.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index f52fd63..02c4660 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1278,7 +1278,6 @@ xfs_bmap_read_extents(
        /* REFERENCED */
        xfs_extnum_t            room;   /* number of entries there's room for */
 
-       bno = NULLFSBLOCK;
        mp = ip->i_mount;
        ifp = XFS_IFORK_PTR(ip, whichfork);
        exntf = (whichfork != XFS_DATA_FORK) ? XFS_EXTFMT_NOSTATE :
@@ -1291,9 +1290,7 @@ xfs_bmap_read_extents(
        ASSERT(level > 0);
        pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
        bno = be64_to_cpu(*pp);
-       ASSERT(bno != NULLFSBLOCK);
-       ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
-       ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);
+
        /*
         * Go down the tree until leaf level is reached, following the first
         * pointer (leftmost) at each level.

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 21e6a6a..2849d3f 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -810,7 +810,8 @@ xfs_btree_read_bufl(
        xfs_daddr_t             d;              /* real disk block address */
        int                     error;
 
-       ASSERT(fsbno != NULLFSBLOCK);
+       if (!XFS_FSB_SANITY_CHECK(mp, fsbno))
+               return -EFSCORRUPTED;
        d = XFS_FSB_TO_DADDR(mp, fsbno);
        error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
                                   mp->m_bsize, lock, &bp, ops);

diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index c2b01d1..3b0fc1a 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -491,7 +491,7 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 #define        XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 
 #define        XFS_FSB_SANITY_CHECK(mp,fsb)    \
-       (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
+       (fsb && XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
                XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 
 /*