Jeff Layton <jlayton@xxxxxxxxxx> writes: > The MDS reserves a set of inodes for its own usage, and these should > never be accessible to clients. Add a new helper to vet a proposed > inode number against that range, and complain loudly and refuse to > create or look it up if it's in it. > > Also, ensure that the MDS doesn't try to delegate inodes that are in > that range or lower. Print a warning if it does, and don't save the > range in the xarray. > > URL: https://tracker.ceph.com/issues/49922 > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > Signed-off-by: Xiubo Li<xiubli@xxxxxxxxxx> > Reviewed-by: Patrick Donnelly <pdonnell@xxxxxxxxxx> > --- > fs/ceph/export.c | 8 ++++++++ > fs/ceph/inode.c | 3 +++ > fs/ceph/mds_client.c | 7 +++++++ > fs/ceph/super.h | 24 ++++++++++++++++++++++++ > 4 files changed, 42 insertions(+) > > This one carves out inode numbers 1..0xff as allowed. There are probably > some in that range that shouldn't be, but most of them qualify. This > should cover the main range we're concerned with anyway. OK, v3 does indeed fix the problem I reported yesterday. Thanks! Cheers, -- Luis > > diff --git a/fs/ceph/export.c b/fs/ceph/export.c > index 17d8c8f4ec89..65540a4429b2 100644 > --- a/fs/ceph/export.c > +++ b/fs/ceph/export.c > @@ -129,6 +129,10 @@ static struct inode *__lookup_inode(struct super_block *sb, u64 ino) > > vino.ino = ino; > vino.snap = CEPH_NOSNAP; > + > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-ESTALE); > + > inode = ceph_find_inode(sb, vino); > if (!inode) { > struct ceph_mds_request *req; > @@ -214,6 +218,10 @@ static struct dentry *__snapfh_to_dentry(struct super_block *sb, > vino.ino = sfh->ino; > vino.snap = sfh->snapid; > } > + > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-ESTALE); > + > inode = ceph_find_inode(sb, vino); > if (inode) > return d_obtain_alias(inode); > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c > index 14a1f7963625..e1c63adb196d 100644 > --- a/fs/ceph/inode.c > +++ b/fs/ceph/inode.c > @@ -56,6 +56,9 @@ struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino) > { > struct inode *inode; > > + if (ceph_vino_is_reserved(vino)) > + return ERR_PTR(-EREMOTEIO); > + > inode = iget5_locked(sb, (unsigned long)vino.ino, ceph_ino_compare, > ceph_set_ino_cb, &vino); > if (!inode) > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c > index 63b53098360c..e5af591d3bd4 100644 > --- a/fs/ceph/mds_client.c > +++ b/fs/ceph/mds_client.c > @@ -440,6 +440,13 @@ static int ceph_parse_deleg_inos(void **p, void *end, > > ceph_decode_64_safe(p, end, start, bad); > ceph_decode_64_safe(p, end, len, bad); > + > + /* Don't accept a delegation of system inodes */ > + if (start < CEPH_INO_SYSTEM_BASE) { > + pr_warn_ratelimited("ceph: ignoring reserved inode range delegation (start=0x%llx len=0x%llx)\n", > + start, len); > + continue; > + } > while (len--) { > int err = xa_insert(&s->s_delegated_inos, ino = start++, > DELEGATED_INO_AVAILABLE, > diff --git a/fs/ceph/super.h b/fs/ceph/super.h > index df0851b9240e..db80d89556b1 100644 > --- a/fs/ceph/super.h > +++ b/fs/ceph/super.h > @@ -529,10 +529,34 @@ static inline int ceph_ino_compare(struct inode *inode, void *data) > ci->i_vino.snap == pvino->snap; > } > > +/* > + * The MDS reserves a set of inodes for its own usage. These should never > + * be accessible by clients, and so the MDS has no reason to ever hand these > + * out. The range is CEPH_MDS_INO_MDSDIR_OFFSET..CEPH_INO_SYSTEM_BASE. > + * > + * These come from src/mds/mdstypes.h in the ceph sources. > + */ > +#define CEPH_MAX_MDS 0x100 > +#define CEPH_NUM_STRAY 10 > +#define CEPH_MDS_INO_MDSDIR_OFFSET (1 * CEPH_MAX_MDS) > +#define CEPH_INO_SYSTEM_BASE ((6*CEPH_MAX_MDS) + (CEPH_MAX_MDS * CEPH_NUM_STRAY)) > + > +static inline bool ceph_vino_is_reserved(const struct ceph_vino vino) > +{ > + if (vino.ino < CEPH_INO_SYSTEM_BASE && > + vino.ino >= CEPH_MDS_INO_MDSDIR_OFFSET) { > + WARN_RATELIMIT(1, "Attempt to access reserved inode number 0x%llx", vino.ino); > + return true; > + } > + return false; > +} > > static inline struct inode *ceph_find_inode(struct super_block *sb, > struct ceph_vino vino) > { > + if (ceph_vino_is_reserved(vino)) > + return NULL; > + > /* > * NB: The hashval will be run through the fs/inode.c hash function > * anyway, so there is no need to squash the inode number down to > -- > > 2.31.1 >
