Re: [PATCH 5.4.y] ALSA: usb-audio: Fix a DMA to stack memory bug

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Found matching upstream commit: f7d306b47a24367302bd4fe846854e07752ffcd9

WARNING: Author mismatch between patch and found commit:
Backport author: "=?UTF-8?q?Beno=C3=AEt=20Sevens?=" <bsevens@google.com>
Commit author: Dan Carpenter <dan.carpenter@linaro.org>


Status in newer kernel trees:
6.12.y | Present (different SHA1: 7f1292f8d4d6)
6.6.y | Not found
6.1.y | Not found
5.15.y | Not found
5.10.y | Not found
5.4.y | Not found

Note: The patch differs from the upstream commit:
---
1:  f7d306b47a24 ! 1:  e539a25e17f7 ALSA: usb-audio: Fix a DMA to stack memory bug
    @@ Commit message
         Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
         Link: https://patch.msgid.link/60e3aa09-039d-46d2-934c-6f123026c2eb@stanley.mountain
         Signed-off-by: Takashi Iwai <tiwai@suse.de>
    +    (cherry picked from commit f7d306b47a24367302bd4fe846854e07752ffcd9)
    +    [Benoît: there is no mbox3 suppport and no __free macro in 5.4]
    +    Signed-off-by: Benoît Sevens <bsevens@google.com>
     
      ## sound/usb/quirks.c ##
     @@ sound/usb/quirks.c: int snd_usb_create_quirk(struct snd_usb_audio *chip,
    @@ sound/usb/quirks.c: int snd_usb_create_quirk(struct snd_usb_audio *chip,
      {
      	struct usb_host_config *config = dev->actconfig;
     -	struct usb_device_descriptor new_device_descriptor;
    -+	struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
    ++	struct usb_device_descriptor *new_device_descriptor = NULL;
      	int err;
      
      	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||
    @@ sound/usb/quirks.c: static int snd_usb_extigy_boot_quirk(struct usb_device *dev,
      		else
     -			memcpy(&dev->descriptor, &new_device_descriptor, sizeof(dev->descriptor));
     +			memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
    ++		kfree(new_device_descriptor);
      		err = usb_reset_configuration(dev);
      		if (err < 0)
      			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
    @@ sound/usb/quirks.c: static void mbox2_setup_48_24_magic(struct usb_device *dev)
      {
      	struct usb_host_config *config = dev->actconfig;
     -	struct usb_device_descriptor new_device_descriptor;
    -+	struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
    ++	struct usb_device_descriptor *new_device_descriptor = NULL;
      	int err;
      	u8 bootresponse[0x12];
      	int fwsize;
    @@ sound/usb/quirks.c: static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
      	else
     -		memcpy(&dev->descriptor, &new_device_descriptor, sizeof(dev->descriptor));
     +		memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
    - 
    - 	err = usb_reset_configuration(dev);
    - 	if (err < 0)
    -@@ sound/usb/quirks.c: static void mbox3_setup_defaults(struct usb_device *dev)
    - static int snd_usb_mbox3_boot_quirk(struct usb_device *dev)
    - {
    - 	struct usb_host_config *config = dev->actconfig;
    --	struct usb_device_descriptor new_device_descriptor;
    -+	struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
    - 	int err;
    - 	int descriptor_size;
    - 
    -@@ sound/usb/quirks.c: static int snd_usb_mbox3_boot_quirk(struct usb_device *dev)
    - 
    - 	dev_dbg(&dev->dev, "MBOX3: device initialised!\n");
    - 
    -+	new_device_descriptor = kmalloc(sizeof(*new_device_descriptor), GFP_KERNEL);
    -+	if (!new_device_descriptor)
    -+		return -ENOMEM;
    -+
    - 	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
    --		&new_device_descriptor, sizeof(new_device_descriptor));
    -+		new_device_descriptor, sizeof(*new_device_descriptor));
    - 	if (err < 0)
    - 		dev_dbg(&dev->dev, "MBOX3: error usb_get_descriptor: %d\n", err);
    --	if (new_device_descriptor.bNumConfigurations > dev->descriptor.bNumConfigurations)
    -+	if (new_device_descriptor->bNumConfigurations > dev->descriptor.bNumConfigurations)
    - 		dev_dbg(&dev->dev, "MBOX3: error too large bNumConfigurations: %d\n",
    --			new_device_descriptor.bNumConfigurations);
    -+			new_device_descriptor->bNumConfigurations);
    - 	else
    --		memcpy(&dev->descriptor, &new_device_descriptor, sizeof(dev->descriptor));
    -+		memcpy(&dev->descriptor, new_device_descriptor, sizeof(dev->descriptor));
    ++	kfree(new_device_descriptor);
      
      	err = usb_reset_configuration(dev);
      	if (err < 0)
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.4.y        |  Success    |  Success   |