[PATCH AUTOSEL 6.4 48/54] rbd: harden get_lock_owner_info() a bit

From: Sasha Levin
Date: Sun Aug 13 2023 - 12:00:45 EST


From: Ilya Dryomov <idryomov@xxxxxxxxx>

[ Upstream commit 8ff2c64c9765446c3cef804fb99da04916603e27 ]

- we want the exclusive lock type, so test for it directly
- use sscanf() to actually parse the lock cookie and avoid admitting
invalid handles
- bail if locker has a blank address

Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/block/rbd.c | 21 +++++++++++++++------
net/ceph/messenger.c | 1 +
2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 7c37c047dbea2..a6210dfae0012 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3862,10 +3862,9 @@ static struct ceph_locker *get_lock_owner_info(struct rbd_device *rbd_dev)
u32 num_lockers;
u8 lock_type;
char *lock_tag;
+ u64 handle;
int ret;

- dout("%s rbd_dev %p\n", __func__, rbd_dev);
-
ret = ceph_cls_lock_info(osdc, &rbd_dev->header_oid,
&rbd_dev->header_oloc, RBD_LOCK_NAME,
&lock_type, &lock_tag, &lockers, &num_lockers);
@@ -3886,18 +3885,28 @@ static struct ceph_locker *get_lock_owner_info(struct rbd_device *rbd_dev)
goto err_busy;
}

- if (lock_type == CEPH_CLS_LOCK_SHARED) {
- rbd_warn(rbd_dev, "shared lock type detected");
+ if (lock_type != CEPH_CLS_LOCK_EXCLUSIVE) {
+ rbd_warn(rbd_dev, "incompatible lock type detected");
goto err_busy;
}

WARN_ON(num_lockers != 1);
- if (strncmp(lockers[0].id.cookie, RBD_LOCK_COOKIE_PREFIX,
- strlen(RBD_LOCK_COOKIE_PREFIX))) {
+ ret = sscanf(lockers[0].id.cookie, RBD_LOCK_COOKIE_PREFIX " %llu",
+ &handle);
+ if (ret != 1) {
rbd_warn(rbd_dev, "locked by external mechanism, cookie %s",
lockers[0].id.cookie);
goto err_busy;
}
+ if (ceph_addr_is_blank(&lockers[0].info.addr)) {
+ rbd_warn(rbd_dev, "locker has a blank address");
+ goto err_busy;
+ }
+
+ dout("%s rbd_dev %p got locker %s%llu@%pISpc/%u handle %llu\n",
+ __func__, rbd_dev, ENTITY_NAME(lockers[0].id.name),
+ &lockers[0].info.addr.in_addr,
+ le32_to_cpu(lockers[0].info.addr.nonce), handle);

out:
kfree(lock_tag);
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index cd7b0bf5369ec..5eb4898cccd4c 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1123,6 +1123,7 @@ bool ceph_addr_is_blank(const struct ceph_entity_addr *addr)
return true;
}
}
+EXPORT_SYMBOL(ceph_addr_is_blank);

int ceph_addr_port(const struct ceph_entity_addr *addr)
{
--
2.40.1