From: Avihai Horon <avihaih@xxxxxxxxxx>
ucma_process_join() allocates struct ucma_multicast mc and frees it if an
error occurs during its run.
Specifically, if an error occurs in copy_to_user(), a use-after-free
might happen in the following scenario:
1. mc struct is allocated.
2. rdma_join_multicast() is called and succeeds. During its run,
cma_iboe_join_multicast() enqueues a work that will later use the
aforementioned mc struct.
3. copy_to_user() is called and fails.
4. mc struct is deallocated.
5. The work that was enqueued by cma_iboe_join_multicast() is run and
calls ucma_create_uevent() which tries to access mc struct (which is
freed by now).
Fix this bug by cancelling the work enqueued by cma_iboe_join_multicast().
Since cma_work_handler() frees struct cma_work, we don't use it in
cma_iboe_join_multicast() so we can safely cancel the work later.
The following syzkaller report revealed it:
BUG: KASAN: use-after-free in ucma_create_uevent+0x2dd/0×3f0
drivers/infiniband/core/ucma.c:272
Read of size 8 at addr ffff88810b3ad110 by task kworker/u8:1/108
CPU: 1 PID: 108 Comm: kworker/u8:1 Not tainted 5.10.0-rc6+ #257
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: rdma_cm cma_work_handler
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xbe/0xf9 lib/dump_stack.c:118
print_address_description.constprop.0+0x3e/0×60 mm/kasan/report.c:385
__kasan_report mm/kasan/report.c:545 [inline]
kasan_report.cold+0x1f/0×37 mm/kasan/report.c:562
ucma_create_uevent+0x2dd/0×3f0 drivers/infiniband/core/ucma.c:272
ucma_event_handler+0xb7/0×3c0 drivers/infiniband/core/ucma.c:349
cma_cm_event_handler+0x5d/0×1c0 drivers/infiniband/core/cma.c:1977
cma_work_handler+0xfa/0×190 drivers/infiniband/core/cma.c:2718
process_one_work+0x54c/0×930 kernel/workqueue.c:2272
worker_thread+0x82/0×830 kernel/workqueue.c:2418
kthread+0x1ca/0×220 kernel/kthread.c:292
ret_from_fork+0x1f/0×30 arch/x86/entry/entry_64.S:296
Allocated by task 359:
kasan_save_stack+0x1b/0×40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc mm/kasan/common.c:461 [inline]
__kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:434
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:664 [inline]
ucma_process_join+0x16e/0×3f0 drivers/infiniband/core/ucma.c:1453
ucma_join_multicast+0xda/0×140 drivers/infiniband/core/ucma.c:1538
ucma_write+0x1f7/0×280 drivers/infiniband/core/ucma.c:1724
vfs_write fs/read_write.c:603 [inline]
vfs_write+0x191/0×4c0 fs/read_write.c:585
ksys_write+0x1a1/0×1e0 fs/read_write.c:658
do_syscall_64+0x2d/0×40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 359:
kasan_save_stack+0x1b/0×40 mm/kasan/common.c:48
kasan_set_track+0x1c/0×30 mm/kasan/common.c:56
kasan_set_free_info+0x1b/0×30 mm/kasan/generic.c:355
__kasan_slab_free+0x112/0×160 mm/kasan/common.c:422
slab_free_hook mm/slub.c:1544 [inline]
slab_free_freelist_hook mm/slub.c:1577 [inline]
slab_free mm/slub.c:3142 [inline]
kfree+0xb3/0×3e0 mm/slub.c:4124
ucma_process_join+0x22d/0×3f0 drivers/infiniband/core/ucma.c:1497
ucma_join_multicast+0xda/0×140 drivers/infiniband/core/ucma.c:1538
ucma_write+0x1f7/0×280 drivers/infiniband/core/ucma.c:1724
vfs_write fs/read_write.c:603 [inline]
vfs_write+0x191/0×4c0 fs/read_write.c:585
ksys_write+0x1a1/0×1e0 fs/read_write.c:658
do_syscall_64+0x2d/0×40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff88810b3ad100
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 16 bytes inside of
192-byte region [ffff88810b3ad100, ffff88810b3ad1c0)
The buggy address belongs to the page:
page:00000000796da98e refcount:1 mapcount:0 mapping:0000000000000000
index:0×0 pfn:0×10b3ad
flags: 0×8000000000000200(slab)
raw: 8000000000000200 dead000000000100 dead000000000122 ffff888100043540
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88810b3ad000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88810b3ad080: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff88810b3ad100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88810b3ad180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88810b3ad200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Fixes: b5de0c60cc30 ("RDMA/cma: Fix use after free race in roce multicast join")
Reported-by: Amit Matityahu <mitm@xxxxxxxxxx>
Signed-off-by: Avihai Horon <avihaih@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
---
Changelog:
v2:
* Delete cma_id_get() in cma_iboe_join_multicast.
* Added WARN_ON(ret) checks.
v1: https://lore.kernel.org/linux-rdma/20210125121556.838290-1-leon@xxxxxxxxxx
---
drivers/infiniband/core/cma.c | 70 ++++++++++++++++++++---------------
1 file changed, 41 insertions(+), 29 deletions(-)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 44cbf2282687..e3fa2c49ffac 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -352,7 +352,13 @@ struct ib_device *cma_get_ib_dev(struct cma_device *cma_dev)
struct cma_multicast {
struct rdma_id_private *id_priv;
- struct ib_sa_multicast *sa_mc;
+ union {
+ struct ib_sa_multicast *sa_mc;
+ struct {
+ struct work_struct work;
+ struct rdma_cm_event event;
+ } iboe_join;
+ };
struct list_head list;
void *context;
struct sockaddr_storage addr;
@@ -1839,6 +1845,8 @@ static void destroy_mc(struct rdma_id_private *id_priv,
cma_igmp_send(ndev, &mgid, false);
dev_put(ndev);
}
+
+ cancel_work_sync(&mc->iboe_join.work);
}
kfree(mc);
}
@@ -2702,6 +2710,28 @@ static int cma_query_ib_route(struct rdma_id_private *id_priv,
return (id_priv->query_id < 0) ? id_priv->query_id : 0;
}
+static void cma_iboe_join_work_handler(struct work_struct *work)
+{
+ struct cma_multicast *mc =
+ container_of(work, struct cma_multicast, iboe_join.work);
+ struct rdma_cm_event *event = &mc->iboe_join.event;
+ struct rdma_id_private *id_priv = mc->id_priv;
+ int ret;
+
+ mutex_lock(&id_priv->handler_mutex);
+ if (READ_ONCE(id_priv->state) == RDMA_CM_DESTROYING ||
+ READ_ONCE(id_priv->state) == RDMA_CM_DEVICE_REMOVAL)
+ goto out_unlock;
+
+ ret = cma_cm_event_handler(id_priv, event);
+ WARN_ON(ret);
+
+out_unlock:
+ mutex_unlock(&id_priv->handler_mutex);
+ if (event->event == RDMA_CM_EVENT_MULTICAST_JOIN)
+ rdma_destroy_ah_attr(&event->param.ud.ah_attr);
+}
+
static void cma_work_handler(struct work_struct *_work)
{
struct cma_work *work = container_of(_work, struct cma_work, work);
@@ -4499,10 +4529,7 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
cma_make_mc_event(status, id_priv, multicast, &event, mc);
ret = cma_cm_event_handler(id_priv, &event);
rdma_destroy_ah_attr(&event.param.ud.ah_attr);
- if (ret) {
- destroy_id_handler_unlock(id_priv);
- return 0;
- }
+ WARN_ON(ret);
out:
mutex_unlock(&id_priv->handler_mutex);
@@ -4614,7 +4641,6 @@ static void cma_iboe_set_mgid(struct sockaddr *addr, union ib_gid *mgid,
static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
struct cma_multicast *mc)
{
- struct cma_work *work;
struct rdma_dev_addr *dev_addr = &id_priv->id.route.addr.dev_addr;
int err = 0;
struct sockaddr *addr = (struct sockaddr *)&mc->addr;
@@ -4628,10 +4654,6 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
if (cma_zero_addr(addr))
return -EINVAL;
- work = kzalloc(sizeof *work, GFP_KERNEL);
- if (!work)
- return -ENOMEM;
-
gid_type = id_priv->cma_dev->default_gid_type[id_priv->id.port_num -
rdma_start_port(id_priv->cma_dev->device)];
cma_iboe_set_mgid(addr, &ib.rec.mgid, gid_type);
@@ -4642,10 +4664,9 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
if (dev_addr->bound_dev_if)
ndev = dev_get_by_index(dev_addr->net, dev_addr->bound_dev_if);
- if (!ndev) {
- err = -ENODEV;
- goto err_free;
- }
+ if (!ndev)
+ return -ENODEV;
+
ib.rec.rate = iboe_get_rate(ndev);
ib.rec.hop_limit = 1;
ib.rec.mtu = iboe_get_mtu(ndev->mtu);
@@ -4663,24 +4684,15 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
err = -ENOTSUPP;
}
dev_put(ndev);
- if (err || !ib.rec.mtu) {
- if (!err)
- err = -EINVAL;
- goto err_free;
- }
+ if (err || !ib.rec.mtu)
+ return err ?: -EINVAL;
+
rdma_ip2gid((struct sockaddr *)&id_priv->id.route.addr.src_addr,
&ib.rec.port_gid);
- work->id = id_priv;
- INIT_WORK(&work->work, cma_work_handler);
- cma_make_mc_event(0, id_priv, &ib, &work->event, mc);
- /* Balances with cma_id_put() in cma_work_handler */
- cma_id_get(id_priv);
- queue_work(cma_wq, &work->work);
+ INIT_WORK(&mc->iboe_join.work, cma_iboe_join_work_handler);
+ cma_make_mc_event(0, id_priv, &ib, &mc->iboe_join.event, mc);
+ queue_work(cma_wq, &mc->iboe_join.work);
return 0;
-
-err_free:
- kfree(work);
- return err;
}
int rdma_join_multicast(struct rdma_cm_id *id, struct sockaddr *addr,
--
2.29.2
