main/libusb: fix handling buggy USB devices

See: https://github.com/libusb/libusb/commit/f38f09da98acc63966b65b72029b1f7f81166bef

Fixes #12426

main/libusb/APKBUILD

@@ -2,7 +2,7 @@
 pkgname=libusb
 pkgver=1.0.24
 _ver=${pkgver/_/-}
-pkgrel=0
+pkgrel=1
 pkgdesc="Library that enables userspace access to USB devices"
 url="https://libusb.info/"
 arch="all"
@@ -11,6 +11,7 @@ subpackages="$pkgname-dev"
 replaces="libusbx"
 makedepends="linux-headers"
 source="https://github.com/libusb/libusb/releases/download/v$pkgver/libusb-$pkgver.tar.bz2
+	f38f09da98acc63966b65b72029b1f7f81166bef.patch
 	"
 
 build() {
@@ -31,4 +32,5 @@ package() {
 	make DESTDIR="$pkgdir" install
 }
 
-sha512sums="5aea36a530aaa15c6dd656d0ed3ce204522c9946d8d39ffbb290dab4a98cda388a2598da4995123d1032324056090bd429e702459626d3e8d7daeebc4e7ff3dc  libusb-1.0.24.tar.bz2"
+sha512sums="5aea36a530aaa15c6dd656d0ed3ce204522c9946d8d39ffbb290dab4a98cda388a2598da4995123d1032324056090bd429e702459626d3e8d7daeebc4e7ff3dc  libusb-1.0.24.tar.bz2
+fdfc2b02eb996661c75ce01652b623afa4339612c2fc84331187ad55ac93d94abe20f48bf3ec891138ebdb8703a29e8b45643518e896f298562f93a5749e014c  f38f09da98acc63966b65b72029b1f7f81166bef.patch"

main/libusb/f38f09da98acc63966b65b72029b1f7f81166bef.patch

+From f38f09da98acc63966b65b72029b1f7f81166bef Mon Sep 17 00:00:00 2001
+From: Chris Dickens <christopher.a.dickens@gmail.com>
+Date: Mon, 8 Feb 2021 11:56:13 -0800
+Subject: [PATCH] linux_usbfs: Gracefully handle buggy devices with a
+ configuration 0
+
+The USB spec states that a configuration value of 0 is reserved and is
+used to indicate the device in not configured (e.g. is in the address
+state). Unfortunately some devices do exist that violate this and use 0
+as the bConfigurationValue of the configuration descriptor.
+
+Improve how the Linux backend handles such non-conformant devices by
+adding special handling around the configuration value 0. Most devices
+will not require this special handling, but for those that do there is
+no way to distinguish between the device being unconfigured and using
+configuration 0.
+
+Closes #850
+
+Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
+---
+ libusb/os/linux_usbfs.c | 94 ++++++++++++++++++++++++++---------------
+ libusb/version_nano.h   |  2 +-
+ 2 files changed, 60 insertions(+), 36 deletions(-)
+
+diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
+index ebf8cfed..3a1894cf 100644
+--- a/libusb/os/linux_usbfs.c
++++ b/libusb/os/linux_usbfs.c
+@@ -128,7 +128,7 @@ struct linux_device_priv {
+ 	void *descriptors;
+ 	size_t descriptors_len;
+ 	struct config_descriptor *config_descriptors;
+-	uint8_t active_config; /* cache val for !sysfs_available  */
++	int active_config; /* cache val for !sysfs_available  */
+ };
+ 
+ struct linux_device_handle_priv {
+@@ -169,6 +169,21 @@ struct linux_transfer_priv {
+ 	int iso_packet_offset;
+ };
+ 
++static int dev_has_config0(struct libusb_device *dev)
++{
++	struct linux_device_priv *priv = usbi_get_device_priv(dev);
++	struct config_descriptor *config;
++	uint8_t idx;
++
++	for (idx = 0; idx < dev->device_descriptor.bNumConfigurations; idx++) {
++		config = &priv->config_descriptors[idx];
++		if (config->desc->bConfigurationValue == 0)
++			return 1;
++	}
++
++	return 0;
++}
++
+ static int get_usbfs_fd(struct libusb_device *dev, mode_t mode, int silent)
+ {
+ 	struct libusb_context *ctx = DEVICE_CTX(dev);
+@@ -574,22 +589,12 @@ static int sysfs_scan_device(struct libusb_context *ctx, const char *devname)
+ }
+ 
+ /* read the bConfigurationValue for a device */
+-static int sysfs_get_active_config(struct libusb_device *dev, uint8_t *config)
++static int sysfs_get_active_config(struct libusb_device *dev, int *config)
+ {
+ 	struct linux_device_priv *priv = usbi_get_device_priv(dev);
+-	int ret, tmp;
+-
+-	ret = read_sysfs_attr(DEVICE_CTX(dev), priv->sysfs_dir, "bConfigurationValue",
+-			      UINT8_MAX, &tmp);
+-	if (ret < 0)
+-		return ret;
+ 
+-	if (tmp == -1)
+-		tmp = 0;	/* unconfigured */
+-
+-	*config = (uint8_t)tmp;
+-
+-	return 0;
++	return read_sysfs_attr(DEVICE_CTX(dev), priv->sysfs_dir, "bConfigurationValue",
++			UINT8_MAX, config);
+ }
+ 
+ int linux_get_device_address(struct libusb_context *ctx, int detached,
+@@ -765,6 +770,9 @@ static int parse_config_descriptors(struct libusb_device *dev)
+ 			}
+ 		}
+ 
++		if (config_desc->bConfigurationValue == 0)
++			usbi_warn(ctx, "device has configuration 0");
++
+ 		priv->config_descriptors[idx].desc = config_desc;
+ 		priv->config_descriptors[idx].actual_len = config_len;
+ 
+@@ -798,7 +806,7 @@ static int op_get_active_config_descriptor(struct libusb_device *dev,
+ {
+ 	struct linux_device_priv *priv = usbi_get_device_priv(dev);
+ 	void *config_desc;
+-	uint8_t active_config;
++	int active_config;
+ 	int r;
+ 
+ 	if (priv->sysfs_dir) {
+@@ -810,12 +818,12 @@ static int op_get_active_config_descriptor(struct libusb_device *dev,
+ 		active_config = priv->active_config;
+ 	}
+ 
+-	if (active_config == 0) {
++	if (active_config == -1) {
+ 		usbi_err(DEVICE_CTX(dev), "device unconfigured");
+ 		return LIBUSB_ERROR_NOT_FOUND;
+ 	}
+ 
+-	r = op_get_config_descriptor_by_value(dev, active_config, &config_desc);
++	r = op_get_config_descriptor_by_value(dev, (uint8_t)active_config, &config_desc);
+ 	if (r < 0)
+ 		return r;
+ 
+@@ -863,17 +871,26 @@ static int usbfs_get_active_config(struct libusb_device *dev, int fd)
+ 
+ 		/* we hit this error path frequently with buggy devices :( */
+ 		usbi_warn(DEVICE_CTX(dev), "get configuration failed, errno=%d", errno);
++
++		/* assume the current configuration is the first one if we have
++		 * the configuration descriptors, otherwise treat the device
++		 * as unconfigured. */
++		if (priv->config_descriptors)
++			priv->active_config = (int)priv->config_descriptors[0].desc->bConfigurationValue;
++		else
++			priv->active_config = -1;
+ 	} else if (active_config == 0) {
+-		/* some buggy devices have a configuration 0, but we're
+-		 * reaching into the corner of a corner case here, so let's
+-		 * not support buggy devices in these circumstances.
+-		 * stick to the specs: a configuration value of 0 means
+-		 * unconfigured. */
+-		usbi_warn(DEVICE_CTX(dev), "active cfg 0? assuming unconfigured device");
++		if (dev_has_config0(dev)) {
++			/* some buggy devices have a configuration 0, but we're
++			 * reaching into the corner of a corner case here. */
++			priv->active_config = 0;
++		} else {
++			priv->active_config = -1;
++		}
++	} else {
++		priv->active_config = (int)active_config;
+ 	}
+ 
+-	priv->active_config = active_config;
+-
+ 	return LIBUSB_SUCCESS;
+ }
+ 
+@@ -1004,9 +1021,9 @@ static int initialize_device(struct libusb_device *dev, uint8_t busnum,
+ 		usbi_warn(ctx, "Missing rw usbfs access; cannot determine "
+ 			       "active configuration descriptor");
+ 		if (priv->config_descriptors)
+-			priv->active_config = priv->config_descriptors[0].desc->bConfigurationValue;
++			priv->active_config = (int)priv->config_descriptors[0].desc->bConfigurationValue;
+ 		else
+-			priv->active_config = 0; /* No config dt */
++			priv->active_config = -1; /* No config dt */
+ 
+ 		return LIBUSB_SUCCESS;
+ 	}
+@@ -1428,22 +1445,27 @@ static int op_get_configuration(struct libusb_device_handle *handle,
+ 	uint8_t *config)
+ {
+ 	struct linux_device_priv *priv = usbi_get_device_priv(handle->dev);
++	int active_config;
+ 	int r;
+ 
+ 	if (priv->sysfs_dir) {
+-		r = sysfs_get_active_config(handle->dev, config);
++		r = sysfs_get_active_config(handle->dev, &active_config);
+ 	} else {
+ 		struct linux_device_handle_priv *hpriv = usbi_get_device_handle_priv(handle);
+ 
+ 		r = usbfs_get_active_config(handle->dev, hpriv->fd);
+ 		if (r == LIBUSB_SUCCESS)
+-			*config = priv->active_config;
++			active_config = priv->active_config;
+ 	}
+ 	if (r < 0)
+ 		return r;
+ 
+-	if (*config == 0)
+-		usbi_err(HANDLE_CTX(handle), "device unconfigured");
++	if (active_config == -1) {
++		usbi_warn(HANDLE_CTX(handle), "device unconfigured");
++		active_config = 0;
++	}
++
++	*config = (uint8_t)active_config;
+ 
+ 	return 0;
+ }
+@@ -1467,11 +1489,13 @@ static int op_set_configuration(struct libusb_device_handle *handle, int config)
+ 		return LIBUSB_ERROR_OTHER;
+ 	}
+ 
+-	if (config == -1)
+-		config = 0;
++	/* if necessary, update our cached active config descriptor */
++	if (!priv->sysfs_dir) {
++		if (config == 0 && !dev_has_config0(handle->dev))
++			config = -1;
+ 
+-	/* update our cached active config descriptor */
+-	priv->active_config = (uint8_t)config;
++		priv->active_config = config;
++	}
+ 
+ 	return LIBUSB_SUCCESS;
+ }