Re: [PATCH 5.15.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

Note: The patch differs from the upstream commit:
---
1:  f7d306b47a24 ! 1:  c80406b311f1 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 5.15]
    +    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: static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
      
      	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));
    - 
    - 	err = usb_reset_configuration(dev);
    - 	if (err < 0)
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y       |  Success    |  Failed    |

Build Errors:
Build error for stable/linux-5.15.y:
    sound/usb/quirks.c: In function 'snd_usb_extigy_boot_quirk':
    sound/usb/quirks.c:594:61: error: expected '=', ',', ';', 'asm' or '__attribute__' before '__free'
      594 |         struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
          |                                                             ^~~~~~
    sound/usb/quirks.c:594:61: error: implicit declaration of function '__free'; did you mean 'kvfree'? [-Werror=implicit-function-declaration]
      594 |         struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
          |                                                             ^~~~~~
          |                                                             kvfree
    sound/usb/quirks.c:594:75: error: lvalue required as left operand of assignment
      594 |         struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
          |                                                                           ^
    sound/usb/quirks.c:595:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
      595 |         int err;
          |         ^~~
    sound/usb/quirks.c:606:17: error: 'new_device_descriptor' undeclared (first use in this function); did you mean 'usb_device_descriptor'?
      606 |                 new_device_descriptor = kmalloc(sizeof(*new_device_descriptor), GFP_KERNEL);
          |                 ^~~~~~~~~~~~~~~~~~~~~
          |                 usb_device_descriptor
    sound/usb/quirks.c:606:17: note: each undeclared identifier is reported only once for each function it appears in
    sound/usb/quirks.c: In function 'snd_usb_mbox2_boot_quirk':
    sound/usb/quirks.c:949:61: error: expected '=', ',', ';', 'asm' or '__attribute__' before '__free'
      949 |         struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
          |                                                             ^~~~~~
    sound/usb/quirks.c:949:75: error: lvalue required as left operand of assignment
      949 |         struct usb_device_descriptor *new_device_descriptor __free(kfree) = NULL;
          |                                                                           ^
    sound/usb/quirks.c:950:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
      950 |         int err;
          |         ^~~
    sound/usb/quirks.c:984:9: error: 'new_device_descriptor' undeclared (first use in this function); did you mean 'usb_device_descriptor'?
      984 |         new_device_descriptor = kmalloc(sizeof(*new_device_descriptor), GFP_KERNEL);
          |         ^~~~~~~~~~~~~~~~~~~~~
          |         usb_device_descriptor
    cc1: some warnings being treated as errors
    make[2]: *** [scripts/Makefile.build:289: sound/usb/quirks.o] Error 1
    make[2]: Target '__build' not remade because of errors.
    make[1]: *** [scripts/Makefile.build:552: sound/usb] Error 2
    make[1]: Target '__build' not remade because of errors.
    make: *** [Makefile:1906: sound] Error 2
    make: Target '__all' not remade because of errors.