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 --- drivers/net/wireguard/queueing.c | 109 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 drivers/net/wireguard/queueing.c (limited to 'drivers/net/wireguard/queueing.c') diff --git a/drivers/net/wireguard/queueing.c b/drivers/net/wireguard/queueing.c new file mode 100644 index 000000000..26d235d15 --- /dev/null +++ b/drivers/net/wireguard/queueing.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld . All Rights Reserved. + */ + +#include "queueing.h" +#include + +struct multicore_worker __percpu * +wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr) +{ + int cpu; + struct multicore_worker __percpu *worker = alloc_percpu(struct multicore_worker); + + if (!worker) + return NULL; + + for_each_possible_cpu(cpu) { + per_cpu_ptr(worker, cpu)->ptr = ptr; + INIT_WORK(&per_cpu_ptr(worker, cpu)->work, function); + } + return worker; +} + +int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function, + unsigned int len) +{ + int ret; + + memset(queue, 0, sizeof(*queue)); + queue->last_cpu = -1; + ret = ptr_ring_init(&queue->ring, len, GFP_KERNEL); + if (ret) + return ret; + queue->worker = wg_packet_percpu_multicore_worker_alloc(function, queue); + if (!queue->worker) { + ptr_ring_cleanup(&queue->ring, NULL); + return -ENOMEM; + } + return 0; +} + +void wg_packet_queue_free(struct crypt_queue *queue, bool purge) +{ + free_percpu(queue->worker); + WARN_ON(!purge && !__ptr_ring_empty(&queue->ring)); + ptr_ring_cleanup(&queue->ring, purge ? __skb_array_destroy_skb : NULL); +} + +#define NEXT(skb) ((skb)->prev) +#define STUB(queue) ((struct sk_buff *)&queue->empty) + +void wg_prev_queue_init(struct prev_queue *queue) +{ + NEXT(STUB(queue)) = NULL; + queue->head = queue->tail = STUB(queue); + queue->peeked = NULL; + atomic_set(&queue->count, 0); + BUILD_BUG_ON( + offsetof(struct sk_buff, next) != offsetof(struct prev_queue, empty.next) - + offsetof(struct prev_queue, empty) || + offsetof(struct sk_buff, prev) != offsetof(struct prev_queue, empty.prev) - + offsetof(struct prev_queue, empty)); +} + +static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb) +{ + WRITE_ONCE(NEXT(skb), NULL); + WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb); +} + +bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb) +{ + if (!atomic_add_unless(&queue->count, 1, MAX_QUEUED_PACKETS)) + return false; + __wg_prev_queue_enqueue(queue, skb); + return true; +} + +struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue) +{ + struct sk_buff *tail = queue->tail, *next = smp_load_acquire(&NEXT(tail)); + + if (tail == STUB(queue)) { + if (!next) + return NULL; + queue->tail = next; + tail = next; + next = smp_load_acquire(&NEXT(next)); + } + if (next) { + queue->tail = next; + atomic_dec(&queue->count); + return tail; + } + if (tail != READ_ONCE(queue->head)) + return NULL; + __wg_prev_queue_enqueue(queue, STUB(queue)); + next = smp_load_acquire(&NEXT(tail)); + if (next) { + queue->tail = next; + atomic_dec(&queue->count); + return tail; + } + return NULL; +} + +#undef NEXT +#undef STUB -- cgit v1.3.1