From 853bc26a7ea39e354b9f8889ae7ad1492ffa28d2 Mon Sep 17 00:00:00 2001 From: alex chen Date: Wed, 15 Nov 2017 17:31:48 -0800 Subject: [PATCH] ocfs2: subsystem.su_mutex is required while accessing the item->ci_parent The subsystem.su_mutex is required while accessing the item->ci_parent, otherwise, NULL pointer dereference to the item->ci_parent will be triggered in the following situation: add node delete node sys_write vfs_write configfs_write_file o2nm_node_store o2nm_node_local_write do_rmdir vfs_rmdir configfs_rmdir mutex_lock(&subsys->su_mutex); unlink_obj item->ci_group = NULL; item->ci_parent = NULL; to_o2nm_cluster_from_node node->nd_item.ci_parent->ci_parent BUG since of NULL pointer dereference to nd_item.ci_parent Moreover, the o2nm_cluster also should be protected by the subsystem.su_mutex. [alex.chen@huawei.com: v2] Link: http://lkml.kernel.org/r/59EEAA69.9080703@huawei.com Link: http://lkml.kernel.org/r/59E9B36A.10700@huawei.com Signed-off-by: Alex Chen Reviewed-by: Jun Piao Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/cluster/nodemanager.c | 63 +++++++++++++++++++++++++++++----- 1 file changed, 55 insertions(+), 8 deletions(-) diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c index a51200ece93d..da64c3a20eeb 100644 --- a/fs/ocfs2/cluster/nodemanager.c +++ b/fs/ocfs2/cluster/nodemanager.c @@ -40,6 +40,9 @@ char *o2nm_fence_method_desc[O2NM_FENCE_METHODS] = { "panic", /* O2NM_FENCE_PANIC */ }; +static inline void o2nm_lock_subsystem(void); +static inline void o2nm_unlock_subsystem(void); + struct o2nm_node *o2nm_get_node_by_num(u8 node_num) { struct o2nm_node *node = NULL; @@ -181,7 +184,10 @@ static struct o2nm_cluster *to_o2nm_cluster_from_node(struct o2nm_node *node) { /* through the first node_set .parent * mycluster/nodes/mynode == o2nm_cluster->o2nm_node_group->o2nm_node */ - return to_o2nm_cluster(node->nd_item.ci_parent->ci_parent); + if (node->nd_item.ci_parent) + return to_o2nm_cluster(node->nd_item.ci_parent->ci_parent); + else + return NULL; } enum { @@ -194,7 +200,7 @@ static ssize_t o2nm_node_num_store(struct config_item *item, const char *page, size_t count) { struct o2nm_node *node = to_o2nm_node(item); - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; unsigned long tmp; char *p = (char *)page; int ret = 0; @@ -214,6 +220,13 @@ static ssize_t o2nm_node_num_store(struct config_item *item, const char *page, !test_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes)) return -EINVAL; /* XXX */ + o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + o2nm_unlock_subsystem(); + return -EINVAL; + } + write_lock(&cluster->cl_nodes_lock); if (cluster->cl_nodes[tmp]) ret = -EEXIST; @@ -226,6 +239,8 @@ static ssize_t o2nm_node_num_store(struct config_item *item, const char *page, set_bit(tmp, cluster->cl_nodes_bitmap); } write_unlock(&cluster->cl_nodes_lock); + o2nm_unlock_subsystem(); + if (ret) return ret; @@ -269,7 +284,7 @@ static ssize_t o2nm_node_ipv4_address_store(struct config_item *item, size_t count) { struct o2nm_node *node = to_o2nm_node(item); - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; int ret, i; struct rb_node **p, *parent; unsigned int octets[4]; @@ -286,6 +301,13 @@ static ssize_t o2nm_node_ipv4_address_store(struct config_item *item, be32_add_cpu(&ipv4_addr, octets[i] << (i * 8)); } + o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + o2nm_unlock_subsystem(); + return -EINVAL; + } + ret = 0; write_lock(&cluster->cl_nodes_lock); if (o2nm_node_ip_tree_lookup(cluster, ipv4_addr, &p, &parent)) @@ -298,6 +320,8 @@ static ssize_t o2nm_node_ipv4_address_store(struct config_item *item, rb_insert_color(&node->nd_ip_node, &cluster->cl_node_ip_tree); } write_unlock(&cluster->cl_nodes_lock); + o2nm_unlock_subsystem(); + if (ret) return ret; @@ -315,7 +339,7 @@ static ssize_t o2nm_node_local_store(struct config_item *item, const char *page, size_t count) { struct o2nm_node *node = to_o2nm_node(item); - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; unsigned long tmp; char *p = (char *)page; ssize_t ret; @@ -333,17 +357,26 @@ static ssize_t o2nm_node_local_store(struct config_item *item, const char *page, !test_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes)) return -EINVAL; /* XXX */ + o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + ret = -EINVAL; + goto out; + } + /* the only failure case is trying to set a new local node * when a different one is already set */ if (tmp && tmp == cluster->cl_has_local && - cluster->cl_local_node != node->nd_num) - return -EBUSY; + cluster->cl_local_node != node->nd_num) { + ret = -EBUSY; + goto out; + } /* bring up the rx thread if we're setting the new local node. */ if (tmp && !cluster->cl_has_local) { ret = o2net_start_listening(node); if (ret) - return ret; + goto out; } if (!tmp && cluster->cl_has_local && @@ -358,7 +391,11 @@ static ssize_t o2nm_node_local_store(struct config_item *item, const char *page, cluster->cl_local_node = node->nd_num; } - return count; + ret = count; + +out: + o2nm_unlock_subsystem(); + return ret; } CONFIGFS_ATTR(o2nm_node_, num); @@ -738,6 +775,16 @@ static struct o2nm_cluster_group o2nm_cluster_group = { }, }; +static inline void o2nm_lock_subsystem(void) +{ + mutex_lock(&o2nm_cluster_group.cs_subsys.su_mutex); +} + +static inline void o2nm_unlock_subsystem(void) +{ + mutex_unlock(&o2nm_cluster_group.cs_subsys.su_mutex); +} + int o2nm_depend_item(struct config_item *item) { return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item);