FAILED: patch "[PATCH] ALSA: usb-audio: Fix a DMA to stack memory bug" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x f7d306b47a24367302bd4fe846854e07752ffcd9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024121040-distant-throng-b534@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f7d306b47a24367302bd4fe846854e07752ffcd9 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <[email protected]>
Date: Mon, 2 Dec 2024 15:57:54 +0300
Subject: [PATCH] ALSA: usb-audio: Fix a DMA to stack memory bug

The usb_get_descriptor() function does DMA so we're not allowed to use a stack buffer for that. Doing DMA to the stack is not portable all architectures. Move the "new_device_descriptor" from being stored on the stack and allocate it with kmalloc() instead.

index 8bc959b60be3..7c9d352864da 100644
@@ -555,7 +555,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
 {
 	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;
 
 	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||

@@ -566,15 +566,19 @@ static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interfac
 				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
 		if (err < 0)
 			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+
+		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, "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, "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)
 			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);

@@ -906,7 +910,7 @@ static void mbox2_setup_48_24_magic(struct usb_device *dev)
 static int snd_usb_mbox2_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;
 	u8 bootresponse[0x12];
 	int fwsize;

@@ -941,15 +945,19 @@ static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
 
 	dev_dbg(&dev->dev, "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, "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, "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)

@@ -1259,7 +1267,7 @@ 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;
 

@@ -1272,15 +1280,19 @@ 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)

From: Dan Carpenter <[email protected]>

The usb_get_descriptor() function does DMA so we're not allowed to use a stack buffer for that. Doing DMA to the stack is not portable all architectures. Move the "new_device_descriptor" from being stored on the stack and allocate it with kmalloc() instead.

---
 sound/usb/quirks.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

index 9d98a0e6a9f4..4c28a27aafdf 100644
@@ -591,7 +591,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
 {
 	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;
 
 	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||

@@ -602,15 +602,19 @@ static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interfac
 				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
 		if (err < 0)
 			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+
+		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, "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, "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)
 			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);

@@ -942,7 +946,7 @@ static void mbox2_setup_48_24_magic(struct usb_device *dev)
 static int snd_usb_mbox2_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;
 	u8 bootresponse[0x12];
 	int fwsize;

@@ -977,15 +981,19 @@ static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
 
 	dev_dbg(&dev->dev, "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, "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, "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)

2.47.1.613.gc27f4b7a9f-goog

Please disregard, this does not build. I will submit a working patch.

[ 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?=" <[email protected]> Commit author: Dan Carpenter <[email protected]>

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

+ (cherry picked from commit f7d306b47a24367302bd4fe846854e07752ffcd9)
+ [Benoît: there is no mbox3 suppport and no __free macro in 5.15]
+ Signed-off-by: Benoît Sevens <[email protected]>

## 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.

From: Dan Carpenter <[email protected]>

The usb_get_descriptor() function does DMA so we're not allowed to use a stack buffer for that. Doing DMA to the stack is not portable all architectures. Move the "new_device_descriptor" from being stored on the stack and allocate it with kmalloc() instead.

---
 sound/usb/quirks.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

index 9d98a0e6a9f4..9f182c448d04 100644
@@ -591,7 +591,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
 {
 	struct usb_host_config *config = dev->actconfig;
-	struct usb_device_descriptor new_device_descriptor;
+	struct usb_device_descriptor *new_device_descriptor = NULL;
 	int err;
 
 	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||

@@ -602,15 +602,20 @@ static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interfac
 				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
 		if (err < 0)
 			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+
+		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, "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, "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)
 			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);

@@ -942,7 +947,7 @@ static void mbox2_setup_48_24_magic(struct usb_device *dev)
 static int snd_usb_mbox2_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 = NULL;
 	int err;
 	u8 bootresponse[0x12];
 	int fwsize;

@@ -977,15 +982,21 @@ static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
 
 	dev_dbg(&dev->dev, "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, "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, "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)

2.47.1.613.gc27f4b7a9f-goog

I see 2 versions of this, which one is correct?

When sending new versions, always properly version them. I'll delete this and wait for a proper v2.

thanks,

greg k-h

[ 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?=" <[email protected]> Commit author: Dan Carpenter <[email protected]>

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: ad2d0ea6f907 ALSA: usb-audio: Fix a DMA to stack memory bug

    @@ Commit message
         Signed-off-by: Dan Carpenter <[email protected]>
         Link: https://patch.msgid.link/[email protected]
         Signed-off-by: Takashi Iwai <[email protected]>
    +    (cherry picked from commit f7d306b47a24367302bd4fe846854e07752ffcd9)
    +    [Benoît: there is no mbox3 suppport and no __free macro in 5.15]
    +    Signed-off-by: Benoît Sevens <[email protected]>
     
      ## 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-5.15.y       |  Success    |  Success   |

From: Dan Carpenter <[email protected]>

The usb_get_descriptor() function does DMA so we're not allowed to use a stack buffer for that. Doing DMA to the stack is not portable all architectures. Move the "new_device_descriptor" from being stored on the stack and allocate it with kmalloc() instead.

---
Changes:
- v2: Remove usage of __free macro which is not yet available in 5.15

 sound/usb/quirks.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

index 9d98a0e6a9f4..9f182c448d04 100644
@@ -591,7 +591,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
 {
 	struct usb_host_config *config = dev->actconfig;
-	struct usb_device_descriptor new_device_descriptor;
+	struct usb_device_descriptor *new_device_descriptor = NULL;
 	int err;
 
 	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||

@@ -602,15 +602,20 @@ static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interfac
 				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
 		if (err < 0)
 			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
+
+		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, "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, "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)
 			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);

@@ -942,7 +947,7 @@ static void mbox2_setup_48_24_magic(struct usb_device *dev)
 static int snd_usb_mbox2_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 = NULL;
 	int err;
 	u8 bootresponse[0x12];
 	int fwsize;

@@ -977,15 +982,21 @@ static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
 
 	dev_dbg(&dev->dev, "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, "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, "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)

2.47.1.613.gc27f4b7a9f-goog

[ 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?=" <[email protected]> Commit author: Dan Carpenter <[email protected]>

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: 483c2942243f ALSA: usb-audio: Fix a DMA to stack memory bug

    @@ Commit message
         Signed-off-by: Dan Carpenter <[email protected]>
         Link: https://patch.msgid.link/[email protected]
         Signed-off-by: Takashi Iwai <[email protected]>
    +    (cherry picked from commit f7d306b47a24367302bd4fe846854e07752ffcd9)
    +    [Benoît: there is no mbox3 suppport and no __free macro in 5.15]
    +    Signed-off-by: Benoît Sevens <[email protected]>
     
      ## 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-5.15.y       |  Success    |  Success   |