On Wed, 2023-05-24 at 18:48 +0300, Amir Goldstein wrote: > The exportfs_encode_*() helpers call the filesystem ->encode_fh() > method which returns a signed int. > > All the in-tree implementations of ->encode_fh() return a positive > integer and FILEID_INVALID (255) for error. > > Fortify the callers for possible future ->encode_fh() implementation > that will return a negative error value. > > name_to_handle_at() would propagate the returned error to the users > if filesystem ->encode_fh() method returns an error. > > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Link: https://lore.kernel.org/linux-fsdevel/ca02955f-1877-4fde-b453-3c1d22794740@kili.mountain/ > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > > Jan, > > This patch is on top of the patches you have queued on fsnotify branch. > > I am not sure about the handling of negative value in nfsfh.c. > > Jeff/Chuck, > > Could you please take a look. > > I've test this patch with fanotify LTP tests, xfstest -g exportfs tests > and some sanity xfstest nfs tests, but I did not try to inject errors > in encode_fh(). > > Please let me know what you think. > > Thanks, > Amir. > > > > fs/fhandle.c | 5 +++-- > fs/nfsd/nfsfh.c | 4 +++- > fs/notify/fanotify/fanotify.c | 2 +- > 3 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/fs/fhandle.c b/fs/fhandle.c > index 4a635cf787fc..fd0d6a3b3699 100644 > --- a/fs/fhandle.c > +++ b/fs/fhandle.c > @@ -57,18 +57,19 @@ static long do_sys_name_to_handle(const struct path *path, > handle_bytes = handle_dwords * sizeof(u32); > handle->handle_bytes = handle_bytes; > if ((handle->handle_bytes > f_handle.handle_bytes) || > - (retval == FILEID_INVALID) || (retval == -ENOSPC)) { > + (retval == FILEID_INVALID) || (retval < 0)) { > /* As per old exportfs_encode_fh documentation > * we could return ENOSPC to indicate overflow > * But file system returned 255 always. So handle > * both the values > */ > + if (retval == FILEID_INVALID || retval == -ENOSPC) > + retval = -EOVERFLOW; > /* > * set the handle size to zero so we copy only > * non variable part of the file_handle > */ > handle_bytes = 0; > - retval = -EOVERFLOW; > } else > retval = 0; > /* copy the mount id */ > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c > index 31e4505c0df3..0f5eacae5f43 100644 > --- a/fs/nfsd/nfsfh.c > +++ b/fs/nfsd/nfsfh.c > @@ -416,9 +416,11 @@ static void _fh_update(struct svc_fh *fhp, struct svc_export *exp, > int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4; > int fh_flags = (exp->ex_flags & NFSEXP_NOSUBTREECHECK) ? 0 : > EXPORT_FH_CONNECTABLE; > + int fileid_type = > + exportfs_encode_fh(dentry, fid, &maxsize, fh_flags); > > fhp->fh_handle.fh_fileid_type = > - exportfs_encode_fh(dentry, fid, &maxsize, fh_flags); > + fileid_type > 0 ? fileid_type : FILEID_INVALID; > fhp->fh_handle.fh_size += maxsize * 4; > } else { > fhp->fh_handle.fh_fileid_type = FILEID_ROOT; > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c > index d2bbf1445a9e..9dac7f6e72d2 100644 > --- a/fs/notify/fanotify/fanotify.c > +++ b/fs/notify/fanotify/fanotify.c > @@ -445,7 +445,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, > dwords = fh_len >> 2; > type = exportfs_encode_fid(inode, buf, &dwords); Are you sure this patch is against the HEAD? My tree has this call as exportfs_encode_inode_fh. > err = -EINVAL; > - if (!type || type == FILEID_INVALID || fh_len != dwords << 2) > + if (type <= 0 || type == FILEID_INVALID || fh_len != dwords << 2) > goto out_err; > > fh->type = type; I'm generally in favor of better guardrails for these sorts of operations, so ACK on the general idea around the patch. -- Jeff Layton <jlayton@xxxxxxxxxx>
