linux_usbfs: Fix parsing of descriptors for multi-configuration devices
Commit e2be556bd2 ("linux_usbfs: Parse config descriptors during device
initialization") introduced a regression for devices with multiple
configurations. The logic that verifies the reported length of the
configuration descriptors failed to count the length of the
configuration descriptor itself and would truncate the actual length by
9 bytes, leading to a parsing error for subsequent descriptors.
Closes #825
Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index fb2ed53..4d2dc8d 100644
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -641,7 +641,12 @@
uint8_t *buffer, size_t len)
{
struct usbi_descriptor_header *header;
- int offset = 0;
+ int offset;
+
+ /* Start seeking past the config descriptor */
+ offset = LIBUSB_DT_CONFIG_SIZE;
+ buffer += LIBUSB_DT_CONFIG_SIZE;
+ len -= LIBUSB_DT_CONFIG_SIZE;
while (len > 0) {
if (len < 2) {
@@ -718,7 +723,7 @@
}
if (priv->sysfs_dir) {
- /*
+ /*
* In sysfs wTotalLength is ignored, instead the kernel returns a
* config descriptor with verified bLength fields, with descriptors
* with an invalid bLength removed.
@@ -727,8 +732,7 @@
int offset;
if (num_configs > 1 && idx < num_configs - 1) {
- offset = seek_to_next_config(ctx, buffer + LIBUSB_DT_CONFIG_SIZE,
- remaining - LIBUSB_DT_CONFIG_SIZE);
+ offset = seek_to_next_config(ctx, buffer, remaining);
if (offset < 0)
return offset;
sysfs_config_len = (uint16_t)offset;
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 61a0a70..578b097 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11585
+#define LIBUSB_NANO 11586
