From: Avihai Horon avihaih@nvidia.com
[ Upstream commit fe454dc31e84f8c14cb8942fcb61666c9f40745b ]
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/0x;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)
Fixes: b5de0c60cc30 ("RDMA/cma: Fix use after free race in roce multicast join") Link: https://lore.kernel.org/r/20210211090517.1278415-1-leon@kernel.org Reported-by: Amit Matityahu mitm@nvidia.com Signed-off-by: Avihai Horon avihaih@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c51b84b2d2f37..e3638f80e1d52 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; @@ -1823,6 +1829,8 @@ 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); } @@ -2683,6 +2691,28 @@ 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); @@ -4478,10 +4508,7 @@ 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); @@ -4604,7 +4631,6 @@ 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; @@ -4618,10 +4644,6 @@ 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); @@ -4632,10 +4654,9 @@ 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); @@ -4653,24 +4674,15 @@ 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,