On 1/7/19 11:52 AM, Darrick J. Wong wrote: > On Mon, Jan 07, 2019 at 04:53:10AM -0500, Su Yanjun wrote: >> For statx syscall, xfs return the wrong result_mask. >> >> Signed-off-by: Su Yanjun <suyj.fnst@xxxxxxxxxxxxxx> >> --- >> fs/xfs/xfs_iops.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c >> index f48ffd7..3811457 100644 >> --- a/fs/xfs/xfs_iops.c >> +++ b/fs/xfs/xfs_iops.c >> @@ -521,6 +521,9 @@ xfs_vn_getattr( >> stat->btime.tv_nsec = ip->i_d.di_crtime.t_nsec; >> } >> } >> + >> + /* Only return mask that we care */ >> + stat->result_mask &= request_mask; > > Why not just: > > stat->result_mask = STATX_BASIC_STATS; > > at the top of the function? > > I don't see the need to mask off result_mask at all, since we could some > day elect to return more than what's in request_mask... > > ...waitaminute, are you seeing garbage in the result_mask that's > returned to userspace? I also noticed the vfs stat functions declare > "struct kstat stat;" without explicitly zeroing the structure fields, > which means (I think) that we can leak stack information if the kernel > isn't built with the stackleak plugin? A clear problem statement and reproducer steps would be hugely useful here. -Eric
