| Message ID | 20180109184729.GF5602@magnolia (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Tue, Jan 09, 2018 at 10:47:29AM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > If a malicious filesystem image contains a block+ format directory > wherein the directory inode's core.mode is set such that > S_ISDIR(core.mode) == 0, and if there are subdirectories of the > corrupted directory, an attempt to traverse up the directory tree will > crash the kernel in __xfs_dir3_data_check. Running the online scrub's > parent checks will tend to do this. > > The crash occurs because the directory inode's d_ops get set to > xfs_dir[23]_nondir_ops (it's not a directory) but the parent pointer > scrubber's indiscriminate call to xfs_readdir proceeds past the ASSERT > if we have non fatal asserts configured. > > Fix the null pointer dereference crash in __xfs_dir3_data_check by > looking for S_ISDIR or wrong d_ops; and teach the parent scrubber > to bail out if it is fed a non-directory "parent". > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > v2: check for wrong d_ops, not individual function pointers > --- Reviewed-by: Brian Foster <bfoster@redhat.com> > fs/xfs/libxfs/xfs_dir2_data.c | 8 ++++++++ > fs/xfs/scrub/parent.c | 2 +- > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/libxfs/xfs_dir2_data.c b/fs/xfs/libxfs/xfs_dir2_data.c > index 3237812..853d9ab 100644 > --- a/fs/xfs/libxfs/xfs_dir2_data.c > +++ b/fs/xfs/libxfs/xfs_dir2_data.c > @@ -73,6 +73,14 @@ __xfs_dir3_data_check( > */ > ops = xfs_dir_get_ops(mp, dp); > > + /* > + * If this isn't a directory, or we don't get handed the dir ops, > + * something is seriously wrong. Bail out. > + */ > + if ((dp && !S_ISDIR(VFS_I(dp)->i_mode)) || > + ops != xfs_dir_get_ops(mp, NULL)) > + return __this_address; > + > hdr = bp->b_addr; > p = (char *)ops->data_entry_p(hdr); > > diff --git a/fs/xfs/scrub/parent.c b/fs/xfs/scrub/parent.c > index dd704fd..0d38514 100644 > --- a/fs/xfs/scrub/parent.c > +++ b/fs/xfs/scrub/parent.c > @@ -171,7 +171,7 @@ xfs_scrub_parent_validate( > error = xfs_iget(mp, sc->tp, dnum, 0, 0, &dp); > if (!xfs_scrub_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error)) > goto out; > - if (dp == sc->ip) { > + if (dp == sc->ip || !S_ISDIR(VFS_I(dp)->i_mode)) { > xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0); > goto out_rele; > } > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/xfs/libxfs/xfs_dir2_data.c b/fs/xfs/libxfs/xfs_dir2_data.c index 3237812..853d9ab 100644 --- a/fs/xfs/libxfs/xfs_dir2_data.c +++ b/fs/xfs/libxfs/xfs_dir2_data.c @@ -73,6 +73,14 @@ __xfs_dir3_data_check( */ ops = xfs_dir_get_ops(mp, dp); + /* + * If this isn't a directory, or we don't get handed the dir ops, + * something is seriously wrong. Bail out. + */ + if ((dp && !S_ISDIR(VFS_I(dp)->i_mode)) || + ops != xfs_dir_get_ops(mp, NULL)) + return __this_address; + hdr = bp->b_addr; p = (char *)ops->data_entry_p(hdr); diff --git a/fs/xfs/scrub/parent.c b/fs/xfs/scrub/parent.c index dd704fd..0d38514 100644 --- a/fs/xfs/scrub/parent.c +++ b/fs/xfs/scrub/parent.c @@ -171,7 +171,7 @@ xfs_scrub_parent_validate( error = xfs_iget(mp, sc->tp, dnum, 0, 0, &dp); if (!xfs_scrub_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error)) goto out; - if (dp == sc->ip) { + if (dp == sc->ip || !S_ISDIR(VFS_I(dp)->i_mode)) { xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0); goto out_rele; }