Commit 1bea2c3e authored by Edward Adam Davis's avatar Edward Adam Davis Committed by Jakub Kicinski
Browse files

ptp: fix corrupted list in ptp_open 



There is no lock protection when writing ptp->tsevqs in ptp_open() and
ptp_release(), which can cause data corruption, use spin lock to avoid this
issue.

Moreover, ptp_release() should not be used to release the queue in ptp_read(),
and it should be deleted altogether.

Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Reported-and-tested-by: default avatar <syzbot+df3f3ef31f60781fa911@syzkaller.appspotmail.com>
Fixes: 8f5de6fb ("ptp: support multiple timestamp event readers")
Signed-off-by: default avatarEdward Adam Davis <eadavis@qq.com>
Link: https://lore.kernel.org/r/tencent_CD19564FFE8DA8A5918DFE92325D92DD8107@qq.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b714ca2c

drivers/ptp/ptp_chardev.c

+12 −9
Original line number Diff line number Diff line
@@ -108,6 +108,7 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) 
		container_of(pccontext->clk, struct ptp_clock, clock);

	struct timestamp_event_queue *queue;

	char debugfsname[32];

	unsigned long flags;



	queue = kzalloc(sizeof(*queue), GFP_KERNEL);

	if (!queue)
@@ -119,7 +120,9 @@ int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode) 
	}

	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);

	spin_lock_init(&queue->lock);

	spin_lock_irqsave(&ptp->tsevqs_lock, flags);

	list_add_tail(&queue->qlist, &ptp->tsevqs);

	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);

	pccontext->private_clkdata = queue;



	/* Debugfs contents */
@@ -139,16 +142,16 @@ int ptp_release(struct posix_clock_context *pccontext) 
{

	struct timestamp_event_queue *queue = pccontext->private_clkdata;

	unsigned long flags;

	struct ptp_clock *ptp =

		container_of(pccontext->clk, struct ptp_clock, clock);



	if (queue) {

	debugfs_remove(queue->debugfs_instance);

	pccontext->private_clkdata = NULL;

		spin_lock_irqsave(&queue->lock, flags);

	spin_lock_irqsave(&ptp->tsevqs_lock, flags);

	list_del(&queue->qlist);

		spin_unlock_irqrestore(&queue->lock, flags);

	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);

	bitmap_free(queue->mask);

	kfree(queue);

	}

	return 0;

}

drivers/ptp/ptp_clock.c

+6 −2
Original line number Diff line number Diff line
@@ -179,11 +179,11 @@ static void ptp_clock_release(struct device *dev) 
	mutex_destroy(&ptp->pincfg_mux);

	mutex_destroy(&ptp->n_vclocks_mux);

	/* Delete first entry */

	spin_lock_irqsave(&ptp->tsevqs_lock, flags);

	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,

				 qlist);

	spin_lock_irqsave(&tsevq->lock, flags);

	list_del(&tsevq->qlist);

	spin_unlock_irqrestore(&tsevq->lock, flags);

	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);

	bitmap_free(tsevq->mask);

	kfree(tsevq);

	debugfs_remove(ptp->debugfs_root);
@@ -247,6 +247,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 
	if (!queue)

		goto no_memory_queue;

	list_add_tail(&queue->qlist, &ptp->tsevqs);

	spin_lock_init(&ptp->tsevqs_lock);

	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);

	if (!queue->mask)

		goto no_memory_bitmap;
@@ -407,6 +408,7 @@ void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 
{

	struct timestamp_event_queue *tsevq;

	struct pps_event_time evt;

	unsigned long flags;



	switch (event->type) {
@@ -415,10 +417,12 @@ void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 


	case PTP_CLOCK_EXTTS:

		/* Enqueue timestamp on selected queues */

		spin_lock_irqsave(&ptp->tsevqs_lock, flags);

		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {

			if (test_bit((unsigned int)event->index, tsevq->mask))

				enqueue_external_timestamp(tsevq, event);

		}

		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);

		wake_up_interruptible(&ptp->tsev_wq);

		break;

drivers/ptp/ptp_private.h

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ struct ptp_clock { 
	struct pps_device *pps_source;

	long dialed_frequency; /* remembers the frequency adjustment */

	struct list_head tsevqs; /* timestamp fifo list */

	spinlock_t tsevqs_lock; /* protects tsevqs from concurrent access */

	struct mutex pincfg_mux; /* protect concurrent info->pin_config access */

	wait_queue_head_t tsev_wq;

	int defunct; /* tells readers to go away when clock is being removed */