From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/net/mctpdevice.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/net/mctpdevice.h (limited to 'include/net/mctpdevice.h') diff --git a/include/net/mctpdevice.h b/include/net/mctpdevice.h new file mode 100644 index 000000000..957d9ef92 --- /dev/null +++ b/include/net/mctpdevice.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Management Component Transport Protocol (MCTP) - device + * definitions. + * + * Copyright (c) 2021 Code Construct + * Copyright (c) 2021 Google + */ + +#ifndef __NET_MCTPDEVICE_H +#define __NET_MCTPDEVICE_H + +#include +#include +#include + +struct mctp_sk_key; + +struct mctp_dev { + struct net_device *dev; + + refcount_t refs; + + unsigned int net; + enum mctp_phys_binding binding; + + const struct mctp_netdev_ops *ops; + + /* Only modified under RTNL. Reads have addrs_lock held */ + u8 *addrs; + size_t num_addrs; + spinlock_t addrs_lock; + + struct rcu_head rcu; +}; + +struct mctp_netdev_ops { + void (*release_flow)(struct mctp_dev *dev, + struct mctp_sk_key *key); +}; + +#define MCTP_INITIAL_DEFAULT_NET 1 + +struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev); +struct mctp_dev *__mctp_dev_get(const struct net_device *dev); + +int mctp_register_netdev(struct net_device *dev, + const struct mctp_netdev_ops *ops, + enum mctp_phys_binding binding); +void mctp_unregister_netdev(struct net_device *dev); + +void mctp_dev_hold(struct mctp_dev *mdev); +void mctp_dev_put(struct mctp_dev *mdev); + +void mctp_dev_set_key(struct mctp_dev *dev, struct mctp_sk_key *key); +void mctp_dev_release_key(struct mctp_dev *dev, struct mctp_sk_key *key); + +#endif /* __NET_MCTPDEVICE_H */ -- cgit v1.3.1