[PATCH] ALSA: pcm: Add more disconnection checks at file ops

[Takashi Iwai]

In the case of hot-disconnection of a PCM device, all file operations
except for close should be rejected.  This patch adds more sanity
checks in the file operation code paths.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/pcm_native.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index ee6d17caf2ce..0c0a825af773 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3234,6 +3234,9 @@ static int snd_pcm_common_ioctl(struct file *file,
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 
+	if (substream->runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
+
 	res = snd_power_wait(substream->pcm->card);
 	if (res < 0)
 		return res;
@@ -3360,6 +3363,9 @@ int snd_pcm_kernel_ioctl(struct snd_pcm_substream *substream,
 	snd_pcm_uframes_t *frames = arg;
 	snd_pcm_sframes_t result;
 	
+	if (substream->runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
+
 	switch (cmd) {
 	case SNDRV_PCM_IOCTL_FORWARD:
 	{
@@ -3402,7 +3408,8 @@ static ssize_t snd_pcm_read(struct file *file, char __user *buf, size_t count,
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 	runtime = substream->runtime;
-	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
 		return -EBADFD;
 	if (!frame_aligned(runtime, count))
 		return -EINVAL;
@@ -3426,7 +3433,8 @@ static ssize_t snd_pcm_write(struct file *file, const char __user *buf,
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 	runtime = substream->runtime;
-	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
 		return -EBADFD;
 	if (!frame_aligned(runtime, count))
 		return -EINVAL;
@@ -3452,7 +3460,8 @@ static ssize_t snd_pcm_readv(struct kiocb *iocb, struct iov_iter *to)
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 	runtime = substream->runtime;
-	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
 		return -EBADFD;
 	if (!iter_is_iovec(to))
 		return -EINVAL;
@@ -3488,7 +3497,8 @@ static ssize_t snd_pcm_writev(struct kiocb *iocb, struct iov_iter *from)
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 	runtime = substream->runtime;
-	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
 		return -EBADFD;
 	if (!iter_is_iovec(from))
 		return -EINVAL;
@@ -3527,6 +3537,9 @@ static __poll_t snd_pcm_poll(struct file *file, poll_table *wait)
 		return ok | EPOLLERR;
 
 	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return ok | EPOLLERR;
+
 	poll_wait(file, &runtime->sleep, wait);
 
 	mask = 0;
@@ -3836,6 +3849,8 @@ static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area)
 	substream = pcm_file->substream;
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
+	if (substream->runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
 
 	offset = area->vm_pgoff << PAGE_SHIFT;
 	switch (offset) {
@@ -3872,6 +3887,8 @@ static int snd_pcm_fasync(int fd, struct file * file, int on)
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
 	return fasync_helper(fd, file, on, &runtime->fasync);
 }
 
-- 
2.31.1