The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to xfs_fs_geometry() with a version number of 3. This code path does not fill in the logsunit member of the passed xfs_fsop_geom_t, leading to the leaking of four bytes of uninitialized stack data to potentially unprivileged callers. Since all other members are filled in all code paths and there are no padding bytes in this structure, it's safe to avoid an expensive memset() in favor of just clearing this one field. Signed-off-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx> --- fs/xfs/xfs_fsops.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index cec89dd..17c4785 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -102,6 +102,7 @@ xfs_fs_geometry( mp->m_sb.sb_logsectsize : BBSIZE; geo->rtsectsize = mp->m_sb.sb_blocksize; geo->dirblocksize = mp->m_dirblksize; + geo->logsunit = 0; } if (new_version >= 4) { geo->flags |= _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs