From: Jeff Layton jlayton@kernel.org
[ Upstream commit d4f6b31d721779d91b5e2f8072478af73b196c34 ]
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@kernel.org Reviewed-by: Xiubo Li xiubli@redhat.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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(+)
diff --git a/fs/ceph/export.c b/fs/ceph/export.c index e088843a7734..80717234410f 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; @@ -212,6 +216,10 @@ 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 2fd1c48ac5d7..179d2ef69a24 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 d87bd852ed96..298cb0b3d28c 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -433,6 +433,13 @@ 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 c48bb30c8d70..1d2fe70439bd 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