[PATCH 5.10 352/545] RDMA/srpt: Fix a use-after-free

Greg Kroah-Hartman
2022-08-19T16:28:26Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit b5605148e6ce36bb21020d49010b617693933128 ]

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>

Link: https://lore.kernel.org/r/20220727193415.1583860-4-bvanassche@acm.org
Reported-by: Li Zhijian <lizhijian@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Fixes: a42d985bd5b2 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 130 ++++++++++++++++++--------
drivers/infiniband/ulp/srpt/ib_srpt.h | 10 +-
2 files changed, 94 insertions(+), 46 deletions(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 211d4e82e4ba..c0ed08fcab48 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;
@@ -2313,31 +2307,35 @@ 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);
@@ -2983,7 +2981,12 @@ 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;
@@ -2998,25 +3001,38 @@ 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)
@@ -3194,10 +3210,6 @@ 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) {
@@ -3298,10 +3310,10 @@ 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;
+ 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;
WARN_ON_ONCE(true);
return NULL;
}
@@ -3816,7 +3828,31 @@ 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) {
+ /* Attempt to create a directory that already exists. */
+ WARN_ON_ONCE(true);
+ 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;
}

/**
@@ -3825,6 +3861,18 @@ 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;
+
+ if (sport->guid_id == port_id)
+ sport->guid_id = NULL;
+ else if (sport->gid_id == port_id)
+ sport->gid_id = NULL;
+ else
+ WARN_ON_ONCE(true);
+
+ 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 978a338f1f0e..2bf381ecd482 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;
--
2.35.1