From: Jeff Layton <jlayton@xxxxxxxxxx>
Al pointed out that a malicious or broken MDS could change the type or
device number of a given inode number. It may also be possible for the
MDS to reuse an old inode number.
Ensure that we never allow fill_inode to change the type part of the
i_mode or the i_rdev unless I_NEW is set. Throw warnings if the MDS ever
changes these on us mid-stream, and return an error.
Don't set i_rdev directly, and rely on init_special_inode to do it.
Also, fix up error handling in the callers of ceph_get_inode.
In handle_cap_grant, check for and warn if the inode type changes, and
only overwrite the mode if it didn't.
Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/ceph/caps.c | 8 +++++++-
fs/ceph/inode.c | 27 +++++++++++++++++++++++----
2 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 570731c4d019..3c03fa37cac4 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3358,7 +3358,13 @@ static void handle_cap_grant(struct inode *inode,
if ((newcaps & CEPH_CAP_AUTH_SHARED) &&
(extra_info->issued & CEPH_CAP_AUTH_EXCL) == 0) {
- inode->i_mode = le32_to_cpu(grant->mode);
+ umode_t mode = le32_to_cpu(grant->mode);
+
+ if (inode_wrong_type(inode, mode))
+ pr_warn_once("inode type changed! (ino %llx.%llx is 0%o, mds says 0%o)\n",
+ ceph_vinop(inode), inode->i_mode, mode);
+ else
+ inode->i_mode = mode;
inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(grant->uid));
inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(grant->gid));
ci->i_btime = extra_info->btime;
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 5db7bf4c6a26..689e3ffd29d7 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -769,11 +769,32 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
bool queue_trunc = false;
bool new_version = false;
bool fill_inline = false;
+ umode_t mode = le32_to_cpu(info->mode);
+ dev_t rdev = le32_to_cpu(info->rdev);
dout("%s %p ino %llx.%llx v %llu had %llu\n", __func__,
inode, ceph_vinop(inode), le64_to_cpu(info->version),
ci->i_version);
+ /* Once I_NEW is cleared, we can't change type or dev numbers */
+ if (inode->i_state & I_NEW) {
+ inode->i_mode = mode;
+ } else {
+ if (inode_wrong_type(inode, mode)) {
+ pr_warn_once("inode type changed! (ino %llx.%llx is 0%o, mds says 0%o)\n",
+ ceph_vinop(inode), inode->i_mode, mode);
+ return -ESTALE;
+ }
+
+ if ((S_ISCHR(mode) || S_ISBLK(mode)) && inode->i_rdev != rdev) {
+ pr_warn_once("dev inode rdev changed! (ino %llx.%llx is %u:%u, mds says %u:%u)\n",
+ ceph_vinop(inode), MAJOR(inode->i_rdev),
+ MINOR(inode->i_rdev), MAJOR(rdev),
+ MINOR(rdev));
+ return -ESTALE;
+ }
+ }
+
info_caps = le32_to_cpu(info->cap.caps);
/* prealloc new cap struct */
@@ -827,8 +848,6 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
issued |= __ceph_caps_dirty(ci);
new_issued = ~issued & info_caps;
- /* update inode */
- inode->i_rdev = le32_to_cpu(info->rdev);
/* directories have fl_stripe_unit set to zero */
if (le32_to_cpu(info->layout.fl_stripe_unit))
inode->i_blkbits =
@@ -840,7 +859,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
if ((new_version || (new_issued & CEPH_CAP_AUTH_SHARED)) &&
(issued & CEPH_CAP_AUTH_EXCL) == 0) {
- inode->i_mode = le32_to_cpu(info->mode);
+ inode->i_mode = mode;
inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(info->uid));
inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(info->gid));
dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
@@ -938,7 +957,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
case S_IFCHR:
case S_IFSOCK:
inode->i_blkbits = PAGE_SHIFT;
- init_special_inode(inode, inode->i_mode, inode->i_rdev);
+ init_special_inode(inode, inode->i_mode, rdev);
inode->i_op = &ceph_file_iops;
break;
case S_IFREG:
--
2.11.0
