On 27/07/2022 05:21, Bart Van Assche wrote:
> Change the LIO port members inside struct srpt_port from regular members
> into pointers. Allocate the LIO port data structures from inside
> srpt_make_tport() and free these from inside srpt_make_tport(). Keep struct
> srpt_device as long as either an RDMA port or a LIO target port is
> associated with it. This patch decouples the lifetime of struct srpt_port
> (controlled by the RDMA core) and struct srpt_port_id (controlled by LIO).
> This patch fixes the following KASAN complaint:
>
> BUG: KASAN: use-after-free in srpt_enable_tpg+0x31/0x70 [ib_srpt]
> Read of size 8 at addr ffff888141cc34b8 by task check/5093
>
> Call Trace:
> <TASK>
> show_stack+0x4e/0x53
> dump_stack_lvl+0x51/0x66
> print_address_description.constprop.0.cold+0xea/0x41e
> print_report.cold+0x90/0x205
> kasan_report+0xb9/0xf0
> __asan_load8+0x69/0x90
> srpt_enable_tpg+0x31/0x70 [ib_srpt]
> target_fabric_tpg_base_enable_store+0xe2/0x140 [target_core_mod]
> configfs_write_iter+0x18b/0x210
> new_sync_write+0x1f2/0x2f0
> vfs_write+0x3e3/0x540
> ksys_write+0xbb/0x140
> __x64_sys_write+0x42/0x50
> do_syscall_64+0x34/0x80
> entry_SYSCALL_64_after_hwframe+0x46/0xb0
> </TASK>
I tested patches with blktests/srp, it works well and the UAF is gone.
> Reported-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
> Cc: Li Zhijian <lizhijian@xxxxxxxxxxx>
> Cc: Hillf Danton <hdanton@xxxxxxxx>
> Cc: Mike Christie <michael.christie@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> drivers/infiniband/ulp/srpt/ib_srpt.c | 133 ++++++++++++++++++--------
> drivers/infiniband/ulp/srpt/ib_srpt.h | 10 +-
> 2 files changed, 96 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
> index 1fbce9225424..8d9eb1210d3b 100644
> --- a/drivers/infiniband/ulp/srpt/ib_srpt.c
> +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
> @@ -565,18 +565,12 @@ static int srpt_refresh_port(struct srpt_port *sport)
> if (ret)
> return ret;
>
> - sport->port_guid_id.wwn.priv = sport;
> srpt_format_guid(sport->guid_name, ARRAY_SIZE(sport->guid_name),
> &sport->gid.global.interface_id);
> - memcpy(sport->port_guid_id.name, sport->guid_name,
> - ARRAY_SIZE(sport->guid_name));
> - sport->port_gid_id.wwn.priv = sport;
> snprintf(sport->gid_name, ARRAY_SIZE(sport->gid_name),
> "0x%016llx%016llx",
> be64_to_cpu(sport->gid.global.subnet_prefix),
> be64_to_cpu(sport->gid.global.interface_id));
> - memcpy(sport->port_gid_id.name, sport->gid_name,
> - ARRAY_SIZE(sport->gid_name));
>
> if (rdma_protocol_iwarp(sport->sdev->device, sport->port))
> return 0;
> @@ -2317,31 +2311,35 @@ static int srpt_cm_req_recv(struct srpt_device *const sdev,
> tag_num = ch->rq_size;
> tag_size = 1; /* ib_srpt does not use se_sess->sess_cmd_map */
>
> - mutex_lock(&sport->port_guid_id.mutex);
> - list_for_each_entry(stpg, &sport->port_guid_id.tpg_list, entry) {
> - if (!IS_ERR_OR_NULL(ch->sess))
> - break;
> - ch->sess = target_setup_session(&stpg->tpg, tag_num,
> + if (sport->guid_id) {
> + mutex_lock(&sport->guid_id->mutex);
> + list_for_each_entry(stpg, &sport->guid_id->tpg_list, entry) {
> + if (!IS_ERR_OR_NULL(ch->sess))
> + break;
> + ch->sess = target_setup_session(&stpg->tpg, tag_num,
> tag_size, TARGET_PROT_NORMAL,
> ch->sess_name, ch, NULL);
> + }
> + mutex_unlock(&sport->guid_id->mutex);
> }
> - mutex_unlock(&sport->port_guid_id.mutex);
>
> - mutex_lock(&sport->port_gid_id.mutex);
> - list_for_each_entry(stpg, &sport->port_gid_id.tpg_list, entry) {
> - if (!IS_ERR_OR_NULL(ch->sess))
> - break;
> - ch->sess = target_setup_session(&stpg->tpg, tag_num,
> + if (sport->gid_id) {
> + mutex_lock(&sport->gid_id->mutex);
> + list_for_each_entry(stpg, &sport->gid_id->tpg_list, entry) {
> + if (!IS_ERR_OR_NULL(ch->sess))
> + break;
> + ch->sess = target_setup_session(&stpg->tpg, tag_num,
> tag_size, TARGET_PROT_NORMAL, i_port_id,
> ch, NULL);
> - if (!IS_ERR_OR_NULL(ch->sess))
> - break;
> - /* Retry without leading "0x" */
> - ch->sess = target_setup_session(&stpg->tpg, tag_num,
> + if (!IS_ERR_OR_NULL(ch->sess))
> + break;
> + /* Retry without leading "0x" */
> + ch->sess = target_setup_session(&stpg->tpg, tag_num,
> tag_size, TARGET_PROT_NORMAL,
> i_port_id + 2, ch, NULL);
> + }
> + mutex_unlock(&sport->gid_id->mutex);
> }
> - mutex_unlock(&sport->port_gid_id.mutex);
>
> if (IS_ERR_OR_NULL(ch->sess)) {
> WARN_ON_ONCE(ch->sess == NULL);
> @@ -2986,7 +2984,12 @@ static int srpt_release_sport(struct srpt_port *sport)
> return 0;
> }
>
> -static struct se_wwn *__srpt_lookup_wwn(const char *name)
> +struct port_and_port_id {
> + struct srpt_port *sport;
> + struct srpt_port_id **port_id;
> +};
> +
> +static struct port_and_port_id __srpt_lookup_port(const char *name)
> {
> struct ib_device *dev;
> struct srpt_device *sdev;
> @@ -3001,25 +3004,38 @@ static struct se_wwn *__srpt_lookup_wwn(const char *name)
> for (i = 0; i < dev->phys_port_cnt; i++) {
> sport = &sdev->port[i];
>
> - if (strcmp(sport->port_guid_id.name, name) == 0)
> - return &sport->port_guid_id.wwn;
> - if (strcmp(sport->port_gid_id.name, name) == 0)
> - return &sport->port_gid_id.wwn;
> + if (strcmp(sport->guid_name, name) == 0) {
> + kref_get(&sdev->refcnt);
> + return (struct port_and_port_id){
> + sport, &sport->guid_id};
> + }
> + if (strcmp(sport->gid_name, name) == 0) {
> + kref_get(&sdev->refcnt);
> + return (struct port_and_port_id){
> + sport, &sport->gid_id};
> + }
> }
> }
>
> - return NULL;
> + return (struct port_and_port_id){};
> }
>
> -static struct se_wwn *srpt_lookup_wwn(const char *name)
> +/**
> + * srpt_lookup_port() - Look up an RDMA port by name
> + * @name: ASCII port name
> + *
> + * Increments the RDMA port reference count if an RDMA port pointer is returned.
> + * The caller must drop that reference count by calling srpt_port_put_ref().
> + */
> +static struct port_and_port_id srpt_lookup_port(const char *name)
> {
> - struct se_wwn *wwn;
> + struct port_and_port_id papi;
>
> spin_lock(&srpt_dev_lock);
> - wwn = __srpt_lookup_wwn(name);
> + papi = __srpt_lookup_port(name);
> spin_unlock(&srpt_dev_lock);
>
> - return wwn;
> + return papi;
> }
>
> static void srpt_free_srq(struct srpt_device *sdev)
> @@ -3198,10 +3214,6 @@ static int srpt_add_one(struct ib_device *device)
> sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
> sport->port_attrib.use_srq = false;
> INIT_WORK(&sport->work, srpt_refresh_port_work);
> - mutex_init(&sport->port_guid_id.mutex);
> - INIT_LIST_HEAD(&sport->port_guid_id.tpg_list);
> - mutex_init(&sport->port_gid_id.mutex);
> - INIT_LIST_HEAD(&sport->port_gid_id.tpg_list);
>
> ret = srpt_refresh_port(sport);
> if (ret) {
> @@ -3295,6 +3307,7 @@ static int srpt_check_false(struct se_portal_group *se_tpg)
>
> static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
> {
> + BUG_ON(!tpg->se_tpg_wwn->priv);
> return tpg->se_tpg_wwn->priv;
> }
>
> @@ -3302,11 +3315,11 @@ static struct srpt_port_id *srpt_wwn_to_sport_id(struct se_wwn *wwn)
> {
> struct srpt_port *sport = wwn->priv;
>
> - if (wwn == &sport->port_guid_id.wwn)
> - return &sport->port_guid_id;
> - if (wwn == &sport->port_gid_id.wwn)
> - return &sport->port_gid_id;
> - WARN_ON_ONCE(true);
> + BUG_ON(!sport);
> + if (sport->guid_id && &sport->guid_id->wwn == wwn)
> + return sport->guid_id;
> + if (sport->gid_id && &sport->gid_id->wwn == wwn)
> + return sport->gid_id;
> return NULL;
> }
>
> @@ -3744,6 +3757,10 @@ static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
> struct srpt_tpg *stpg;
> int res = -ENOMEM;
>
> + if (!sport_id) {
> + pr_err("RDMA port does not exist\n");
> + return ERR_PTR(-EINVAL);
> + }
> stpg = kzalloc(sizeof(*stpg), GFP_KERNEL);
> if (!stpg)
> return ERR_PTR(res);
> @@ -3790,7 +3807,28 @@ static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
> struct config_group *group,
> const char *name)
> {
> - return srpt_lookup_wwn(name) ? : ERR_PTR(-EINVAL);
> + struct port_and_port_id papi = srpt_lookup_port(name);
> + struct srpt_port *sport = papi.sport;
> + struct srpt_port_id *port_id;
> +
> + if (!papi.port_id)
> + return ERR_PTR(-EINVAL);
> + if (*papi.port_id)
> + return &(*papi.port_id)->wwn;
> + port_id = kzalloc(sizeof(*port_id), GFP_KERNEL);
> + if (!port_id) {
> + srpt_sdev_put(sport->sdev);
> + return ERR_PTR(-ENOMEM);
> + }
> + mutex_init(&port_id->mutex);
> + INIT_LIST_HEAD(&port_id->tpg_list);
> + port_id->wwn.priv = sport;
> + memcpy(port_id->name, port_id == sport->guid_id ? sport->guid_name :
> + sport->gid_name, ARRAY_SIZE(port_id->name));
> +
> + *papi.port_id = port_id;
> +
> + return &port_id->wwn;
> }
>
> /**
> @@ -3799,6 +3837,17 @@ static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
> */
> static void srpt_drop_tport(struct se_wwn *wwn)
> {
> + struct srpt_port_id *port_id = container_of(wwn, typeof(*port_id), wwn);
> + struct srpt_port *sport = wwn->priv;
> +
> + BUG_ON(!sport);
> + if (sport->guid_id == port_id)
> + sport->guid_id = NULL;
> + else if (sport->gid_id == port_id)
> + sport->gid_id = NULL;
> +
> + srpt_sdev_put(sport->sdev);
> + kfree(port_id);
> }
>
> static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
> diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
> index 0cb867d580f1..4c46b301eea1 100644
> --- a/drivers/infiniband/ulp/srpt/ib_srpt.h
> +++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
> @@ -393,7 +393,7 @@ struct srpt_port_id {
> };
>
> /**
> - * struct srpt_port - information associated by SRPT with a single IB port
> + * struct srpt_port - SRPT RDMA port information
> * @sdev: backpointer to the HCA information.
> * @mad_agent: per-port management datagram processing information.
> * @enabled: Whether or not this target port is enabled.
> @@ -403,9 +403,9 @@ struct srpt_port_id {
> * @gid: cached value of the port's gid.
> * @work: work structure for refreshing the aforementioned cached values.
> * @guid_name: port name in GUID format.
> - * @port_guid_id: LIO target port information for the port name in GUID format.
> + * @guid_id: LIO target port information for the port name in GUID format.
> * @gid_name: port name in GID format.
> - * @port_gid_id: LIO target port information for the port name in GID format.
> + * @gid_id: LIO target port information for the port name in GID format.
> * @port_attrib: Port attributes that can be accessed through configfs.
> * @refcount: Number of objects associated with this port.
> * @freed_channels: Completion that will be signaled once @refcount becomes 0.
> @@ -422,9 +422,9 @@ struct srpt_port {
> union ib_gid gid;
> struct work_struct work;
> char guid_name[64];
> - struct srpt_port_id port_guid_id;
> + struct srpt_port_id *guid_id;
> char gid_name[64];
> - struct srpt_port_id port_gid_id;
> + struct srpt_port_id *gid_id;
> struct srpt_port_attrib port_attrib;
> atomic_t refcount;
> struct completion *freed_channels;
