[PATCH 4.20 023/171] IB/ipoib: Fix for use-after-free in ipoib_cm_tx_start

Greg Kroah-Hartman
2019-03-12T17:12:21Z

[ Upstream commit 6ab4aba00f811a5265acc4d3eb1863bb3ca60562 ]

The following BUG was reported by kasan:

BUG: KASAN: use-after-free in ipoib_cm_tx_start+0x430/0x1390 [ib_ipoib]
Read of size 80 at addr ffff88034c30bcd0 by task kworker/u16:1/24020

Workqueue: ipoib_wq ipoib_cm_tx_start [ib_ipoib]
Call Trace:
dump_stack+0x9a/0xeb
print_address_description+0xe3/0x2e0
kasan_report+0x18a/0x2e0
? ipoib_cm_tx_start+0x430/0x1390 [ib_ipoib]
memcpy+0x1f/0x50
ipoib_cm_tx_start+0x430/0x1390 [ib_ipoib]
? kvm_clock_read+0x1f/0x30
? ipoib_cm_skb_reap+0x610/0x610 [ib_ipoib]
? __lock_is_held+0xc2/0x170
? process_one_work+0x880/0x1960
? process_one_work+0x912/0x1960
process_one_work+0x912/0x1960
? wq_pool_ids_show+0x310/0x310
? lock_acquire+0x145/0x440
worker_thread+0x87/0xbb0
? process_one_work+0x1960/0x1960
kthread+0x314/0x3d0
? kthread_create_worker_on_cpu+0xc0/0xc0
ret_from_fork+0x3a/0x50

Allocated by task 0:
kasan_kmalloc+0xa0/0xd0
kmem_cache_alloc_trace+0x168/0x3e0
path_rec_create+0xa2/0x1f0 [ib_ipoib]
ipoib_start_xmit+0xa98/0x19e0 [ib_ipoib]
dev_hard_start_xmit+0x159/0x8d0
sch_direct_xmit+0x226/0xb40
__dev_queue_xmit+0x1d63/0x2950
neigh_update+0x889/0x1770
arp_process+0xc47/0x21f0
arp_rcv+0x462/0x760
__netif_receive_skb_core+0x1546/0x2da0
netif_receive_skb_internal+0xf2/0x590
napi_gro_receive+0x28e/0x390
ipoib_ib_handle_rx_wc_rss+0x873/0x1b60 [ib_ipoib]
ipoib_rx_poll_rss+0x17d/0x320 [ib_ipoib]
net_rx_action+0x427/0xe30
__do_softirq+0x28e/0xc42

Freed by task 26680:
__kasan_slab_free+0x11d/0x160
kfree+0xf5/0x360
ipoib_flush_paths+0x532/0x9d0 [ib_ipoib]
ipoib_set_mode_rss+0x1ad/0x560 [ib_ipoib]
set_mode+0xc8/0x150 [ib_ipoib]
kernfs_fop_write+0x279/0x440
__vfs_write+0xd8/0x5c0
vfs_write+0x15e/0x470
ksys_write+0xb8/0x180
do_syscall_64+0x9b/0x420
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88034c30bcc8
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
512-byte region [ffff88034c30bcc8, ffff88034c30bec8)
The buggy address belongs to the page:

The following race between change mode and xmit flow is the reason for
this use-after-free:

Change mode Send packet 1 to GID XX Send packet 2 to GID XX
| | |
start | |
| | |
| | |
| Create new path for GID XX |
| and update neigh path |
| | |
| | |
| | |
flush_paths | |
| |
queue_work(cm.start_task) |
| Path for GID XX not found
| create new path
|
|
start_task runs with old
released path

There is no locking to protect the lifetime of the path through the
ipoib_cm_tx struct, so delete it entirely and always use the newly looked
up path under the priv->lock.

Fixes: 546481c2816e ("IB/ipoib: Fix memory corruption in ipoib cm mode connect flow")
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Reviewed-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/ulp/ipoib/ipoib.h | 1 -
drivers/infiniband/ulp/ipoib/ipoib_cm.c | 3 +--
2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index 1da119d901a9..73e808c1e6ad 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -248,7 +248,6 @@ struct ipoib_cm_tx {
struct list_head list;
struct net_device *dev;
struct ipoib_neigh *neigh;
- struct ipoib_path *path;
struct ipoib_tx_buf *tx_ring;
unsigned int tx_head;
unsigned int tx_tail;
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 0428e01e8f69..aa9dcfc36cd3 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -1312,7 +1312,6 @@ struct ipoib_cm_tx *ipoib_cm_create_tx(struct net_device *dev, struct ipoib_path

neigh->cm = tx;
tx->neigh = neigh;
- tx->path = path;
tx->dev = dev;
list_add(&tx->list, &priv->cm.start_list);
set_bit(IPOIB_FLAG_INITIALIZED, &tx->flags);
@@ -1371,7 +1370,7 @@ static void ipoib_cm_tx_start(struct work_struct *work)
neigh->daddr + QPN_AND_OPTIONS_OFFSET);
goto free_neigh;
}
- memcpy(&pathrec, &p->path->pathrec, sizeof(pathrec));
+ memcpy(&pathrec, &path->pathrec, sizeof(pathrec));

spin_unlock_irqrestore(&priv->lock, flags);
netif_tx_unlock_bh(dev);
--
2.19.1