63 lines
2.2 KiB
Diff
63 lines
2.2 KiB
Diff
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From 623e2a995d156e115c91f56a3ec691bdc333df8b Mon Sep 17 00:00:00 2001
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From: Chris Dickens <christopher.a.dickens@gmail.com>
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Date: Sun, 13 Dec 2020 15:49:19 -0800
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Subject: [PATCH 1/1] linux_usbfs: Fix parsing of descriptors for
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multi-configuration devices
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Commit e2be556bd2 ("linux_usbfs: Parse config descriptors during device
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initialization") introduced a regression for devices with multiple
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configurations. The logic that verifies the reported length of the
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configuration descriptors failed to count the length of the
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configuration descriptor itself and would truncate the actual length by
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9 bytes, leading to a parsing error for subsequent descriptors.
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Closes #825
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Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
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(cherry picked from commit f6d2cb561402c3b6d3627c0eb89e009b503d9067)
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Signed-off-by: John Keeping <john@metanate.com>
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---
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libusb/os/linux_usbfs.c | 12 ++++++++----
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1 file changed, 8 insertions(+), 4 deletions(-)
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diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
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index fb2ed53..4d2dc8d 100644
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--- a/libusb/os/linux_usbfs.c
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+++ b/libusb/os/linux_usbfs.c
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@@ -641,7 +641,12 @@ static int seek_to_next_config(struct libusb_context *ctx,
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uint8_t *buffer, size_t len)
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{
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struct usbi_descriptor_header *header;
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- int offset = 0;
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+ int offset;
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+
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+ /* Start seeking past the config descriptor */
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+ offset = LIBUSB_DT_CONFIG_SIZE;
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+ buffer += LIBUSB_DT_CONFIG_SIZE;
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+ len -= LIBUSB_DT_CONFIG_SIZE;
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while (len > 0) {
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if (len < 2) {
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@@ -718,7 +723,7 @@ static int parse_config_descriptors(struct libusb_device *dev)
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}
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if (priv->sysfs_dir) {
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- /*
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+ /*
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* In sysfs wTotalLength is ignored, instead the kernel returns a
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* config descriptor with verified bLength fields, with descriptors
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* with an invalid bLength removed.
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@@ -727,8 +732,7 @@ static int parse_config_descriptors(struct libusb_device *dev)
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int offset;
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if (num_configs > 1 && idx < num_configs - 1) {
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- offset = seek_to_next_config(ctx, buffer + LIBUSB_DT_CONFIG_SIZE,
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- remaining - LIBUSB_DT_CONFIG_SIZE);
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+ offset = seek_to_next_config(ctx, buffer, remaining);
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if (offset < 0)
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return offset;
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sysfs_config_len = (uint16_t)offset;
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--
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2.30.1
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