From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 1 Apr 2024 08:36:36 +0000 (+0200)
Subject: 5.4-stable patches
X-Git-Tag: v6.7.12~84
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d14c5834bcceed1fd69e4f7cd8184cffb6a63e7b;p=thirdparty%2Fkernel%2Fstable-queue.git

5.4-stable patches

added patches:
	alsa-sh-aica-reorder-cleanup-operations-to-avoid-uaf-bugs.patch
---

diff --git a/queue-5.4/alsa-sh-aica-reorder-cleanup-operations-to-avoid-uaf-bugs.patch b/queue-5.4/alsa-sh-aica-reorder-cleanup-operations-to-avoid-uaf-bugs.patch
new file mode 100644
index 00000000000..7b19df40310
--- /dev/null
+++ b/queue-5.4/alsa-sh-aica-reorder-cleanup-operations-to-avoid-uaf-bugs.patch
@@ -0,0 +1,95 @@
+From 051e0840ffa8ab25554d6b14b62c9ab9e4901457 Mon Sep 17 00:00:00 2001
+From: Duoming Zhou <duoming@zju.edu.cn>
+Date: Tue, 26 Mar 2024 17:42:38 +0800
+Subject: ALSA: sh: aica: reorder cleanup operations to avoid UAF bugs
+
+From: Duoming Zhou <duoming@zju.edu.cn>
+
+commit 051e0840ffa8ab25554d6b14b62c9ab9e4901457 upstream.
+
+The dreamcastcard->timer could schedule the spu_dma_work and the
+spu_dma_work could also arm the dreamcastcard->timer.
+
+When the snd_pcm_substream is closing, the aica_channel will be
+deallocated. But it could still be dereferenced in the worker
+thread. The reason is that del_timer() will return directly
+regardless of whether the timer handler is running or not and
+the worker could be rescheduled in the timer handler. As a result,
+the UAF bug will happen. The racy situation is shown below:
+
+      (Thread 1)                 |      (Thread 2)
+snd_aicapcm_pcm_close()          |
+ ...                             |  run_spu_dma() //worker
+                                 |    mod_timer()
+  flush_work()                   |
+  del_timer()                    |  aica_period_elapsed() //timer
+  kfree(dreamcastcard->channel)  |    schedule_work()
+                                 |  run_spu_dma() //worker
+  ...                            |    dreamcastcard->channel-> //USE
+
+In order to mitigate this bug and other possible corner cases,
+call mod_timer() conditionally in run_spu_dma(), then implement
+PCM sync_stop op to cancel both the timer and worker. The sync_stop
+op will be called from PCM core appropriately when needed.
+
+Fixes: 198de43d758c ("[ALSA] Add ALSA support for the SEGA Dreamcast PCM device")
+Suggested-by: Takashi Iwai <tiwai@suse.de>
+Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
+Message-ID: <20240326094238.95442-1-duoming@zju.edu.cn>
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ sound/sh/aica.c |   17 ++++++++++++++---
+ 1 file changed, 14 insertions(+), 3 deletions(-)
+
+--- a/sound/sh/aica.c
++++ b/sound/sh/aica.c
+@@ -279,7 +279,8 @@ static void run_spu_dma(struct work_stru
+ 		dreamcastcard->clicks++;
+ 		if (unlikely(dreamcastcard->clicks >= AICA_PERIOD_NUMBER))
+ 			dreamcastcard->clicks %= AICA_PERIOD_NUMBER;
+-		mod_timer(&dreamcastcard->timer, jiffies + 1);
++		if (snd_pcm_running(dreamcastcard->substream))
++			mod_timer(&dreamcastcard->timer, jiffies + 1);
+ 	}
+ }
+ 
+@@ -291,6 +292,8 @@ static void aica_period_elapsed(struct t
+ 	/*timer function - so cannot sleep */
+ 	int play_period;
+ 	struct snd_pcm_runtime *runtime;
++	if (!snd_pcm_running(substream))
++		return;
+ 	runtime = substream->runtime;
+ 	dreamcastcard = substream->pcm->private_data;
+ 	/* Have we played out an additional period? */
+@@ -351,12 +354,19 @@ static int snd_aicapcm_pcm_open(struct s
+ 	return 0;
+ }
+ 
++static int snd_aicapcm_pcm_sync_stop(struct snd_pcm_substream *substream)
++{
++	struct snd_card_aica *dreamcastcard = substream->pcm->private_data;
++
++	del_timer_sync(&dreamcastcard->timer);
++	cancel_work_sync(&dreamcastcard->spu_dma_work);
++	return 0;
++}
++
+ static int snd_aicapcm_pcm_close(struct snd_pcm_substream
+ 				 *substream)
+ {
+ 	struct snd_card_aica *dreamcastcard = substream->pcm->private_data;
+-	flush_work(&(dreamcastcard->spu_dma_work));
+-	del_timer(&dreamcastcard->timer);
+ 	dreamcastcard->substream = NULL;
+ 	kfree(dreamcastcard->channel);
+ 	spu_disable();
+@@ -422,6 +432,7 @@ static const struct snd_pcm_ops snd_aica
+ 	.prepare = snd_aicapcm_pcm_prepare,
+ 	.trigger = snd_aicapcm_pcm_trigger,
+ 	.pointer = snd_aicapcm_pcm_pointer,
++	.sync_stop = snd_aicapcm_pcm_sync_stop,
+ };
+ 
+ /* TO DO: set up to handle more than one pcm instance */
diff --git a/queue-5.4/series b/queue-5.4/series
index 4a6a8624c14..a7f2dddfe88 100644
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -115,3 +115,4 @@ exec-fix-nommu-linux_binprm-exec-in-transfer_args_to_stack.patch
 mmc-core-initialize-mmc_blk_ioc_data.patch
 mmc-core-avoid-negative-index-with-array-access.patch
 usb-cdc-wdm-close-race-between-read-and-workqueue.patch
+alsa-sh-aica-reorder-cleanup-operations-to-avoid-uaf-bugs.patch