1 files changed, 253 insertions, 0 deletions
diff --git a/third_party/rust/authenticator/src/hidproto.rs b/third_party/rust/authenticator/src/hidproto.rs
new file mode 100644
index 0000000000..5679e6e5d7
--- /dev/null
+++ b/third_party/rust/authenticator/src/hidproto.rs
@@ -0,0 +1,253 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Shared code for platforms that use raw HID access (Linux, FreeBSD, etc.)
+
+#![cfg_attr(
+    feature = "cargo-clippy",
+    allow(clippy::cast_lossless, clippy::needless_lifetimes)
+)]
+
+use std::io;
+use std::mem;
+
+use crate::consts::{FIDO_USAGE_PAGE, FIDO_USAGE_U2FHID, INIT_HEADER_SIZE, MAX_HID_RPT_SIZE};
+
+// The 4 MSBs (the tag) are set when it's a long item.
+const HID_MASK_LONG_ITEM_TAG: u8 = 0b1111_0000;
+// The 2 LSBs denote the size of a short item.
+const HID_MASK_SHORT_ITEM_SIZE: u8 = 0b0000_0011;
+// The 6 MSBs denote the tag (4) and type (2).
+const HID_MASK_ITEM_TAGTYPE: u8 = 0b1111_1100;
+// tag=0000, type=10 (local)
+const HID_ITEM_TAGTYPE_USAGE: u8 = 0b0000_1000;
+// tag=0000, type=01 (global)
+const HID_ITEM_TAGTYPE_USAGE_PAGE: u8 = 0b0000_0100;
+// tag=1000, type=00 (main)
+const HID_ITEM_TAGTYPE_INPUT: u8 = 0b1000_0000;
+// tag=1001, type=00 (main)
+const HID_ITEM_TAGTYPE_OUTPUT: u8 = 0b1001_0000;
+// tag=1001, type=01 (global)
+const HID_ITEM_TAGTYPE_REPORT_COUNT: u8 = 0b1001_0100;
+
+pub struct ReportDescriptor {
+    pub value: Vec<u8>,
+}
+
+impl ReportDescriptor {
+    fn iter(self) -> ReportDescriptorIterator {
+        ReportDescriptorIterator::new(self)
+    }
+}
+
+#[derive(Debug)]
+pub enum Data {
+    UsagePage { data: u32 },
+    Usage { data: u32 },
+    Input,
+    Output,
+    ReportCount { data: u32 },
+}
+
+pub struct ReportDescriptorIterator {
+    desc: ReportDescriptor,
+    pos: usize,
+}
+
+impl ReportDescriptorIterator {
+    fn new(desc: ReportDescriptor) -> Self {
+        Self { desc, pos: 0 }
+    }
+
+    fn next_item(&mut self) -> Option<Data> {
+        let item = get_hid_item(&self.desc.value[self.pos..]);
+        if item.is_none() {
+            self.pos = self.desc.value.len(); // Close, invalid data.
+            return None;
+        }
+
+        let (tag_type, key_len, data) = item.unwrap();
+
+        // Advance if we have a valid item.
+        self.pos += key_len + data.len();
+
+        // We only check short items.
+        if key_len > 1 {
+            return None; // Check next item.
+        }
+
+        // Short items have max. length of 4 bytes.
+        assert!(data.len() <= mem::size_of::<u32>());
+
+        // Convert data bytes to a uint.
+        let data = read_uint_le(data);
+        match tag_type {
+            HID_ITEM_TAGTYPE_USAGE_PAGE => Some(Data::UsagePage { data }),
+            HID_ITEM_TAGTYPE_USAGE => Some(Data::Usage { data }),
+            HID_ITEM_TAGTYPE_INPUT => Some(Data::Input),
+            HID_ITEM_TAGTYPE_OUTPUT => Some(Data::Output),
+            HID_ITEM_TAGTYPE_REPORT_COUNT => Some(Data::ReportCount { data }),
+            _ => None,
+        }
+    }
+}
+
+impl Iterator for ReportDescriptorIterator {
+    type Item = Data;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.pos >= self.desc.value.len() {
+            return None;
+        }
+
+        self.next_item().or_else(|| self.next())
+    }
+}
+
+fn get_hid_item<'a>(buf: &'a [u8]) -> Option<(u8, usize, &'a [u8])> {
+    if (buf[0] & HID_MASK_LONG_ITEM_TAG) == HID_MASK_LONG_ITEM_TAG {
+        get_hid_long_item(buf)
+    } else {
+        get_hid_short_item(buf)
+    }
+}
+
+fn get_hid_long_item<'a>(buf: &'a [u8]) -> Option<(u8, usize, &'a [u8])> {
+    // A valid long item has at least three bytes.
+    if buf.len() < 3 {
+        return None;
+    }
+
+    let len = buf[1] as usize;
+
+    // Ensure that there are enough bytes left in the buffer.
+    if len > buf.len() - 3 {
+        return None;
+    }
+
+    Some((buf[2], 3 /* key length */, &buf[3..]))
+}
+
+fn get_hid_short_item<'a>(buf: &'a [u8]) -> Option<(u8, usize, &'a [u8])> {
+    // This is a short item. The bottom two bits of the key
+    // contain the length of the data section (value) for this key.
+    let len = match buf[0] & HID_MASK_SHORT_ITEM_SIZE {
+        s @ 0..=2 => s as usize,
+        _ => 4, /* _ == 3 */
+    };
+
+    // Ensure that there are enough bytes left in the buffer.
+    if len > buf.len() - 1 {
+        return None;
+    }
+
+    Some((
+        buf[0] & HID_MASK_ITEM_TAGTYPE,
+        1, /* key length */
+        &buf[1..=len],
+    ))
+}
+
+fn read_uint_le(buf: &[u8]) -> u32 {
+    assert!(buf.len() <= 4);
+    // Parse the number in little endian byte order.
+    buf.iter()
+        .rev()
+        .fold(0, |num, b| (num << 8) | (u32::from(*b)))
+}
+
+pub fn has_fido_usage(desc: ReportDescriptor) -> bool {
+    let mut usage_page = None;
+    let mut usage = None;
+
+    for data in desc.iter() {
+        match data {
+            Data::UsagePage { data } => usage_page = Some(data),
+            Data::Usage { data } => usage = Some(data),
+            _ => {}
+        }
+
+        // Check the values we found.
+        if let (Some(usage_page), Some(usage)) = (usage_page, usage) {
+            return usage_page == u32::from(FIDO_USAGE_PAGE)
+                && usage == u32::from(FIDO_USAGE_U2FHID);
+        }
+    }
+
+    false
+}
+
+pub fn read_hid_rpt_sizes(desc: ReportDescriptor) -> io::Result<(usize, usize)> {
+    let mut in_rpt_count = None;
+    let mut out_rpt_count = None;
+    let mut last_rpt_count = None;
+
+    for data in desc.iter() {
+        match data {
+            Data::ReportCount { data } => {
+                if last_rpt_count != None {
+                    return Err(io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        "Duplicate HID_ReportCount",
+                    ));
+                }
+                last_rpt_count = Some(data as usize);
+            }
+            Data::Input => {
+                if last_rpt_count.is_none() {
+                    return Err(io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        "HID_Input should be preceded by HID_ReportCount",
+                    ));
+                }
+                if in_rpt_count.is_some() {
+                    return Err(io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        "Duplicate HID_ReportCount",
+                    ));
+                }
+                in_rpt_count = last_rpt_count;
+                last_rpt_count = None
+            }
+            Data::Output => {
+                if last_rpt_count.is_none() {
+                    return Err(io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        "HID_Output should be preceded by HID_ReportCount",
+                    ));
+                }
+                if out_rpt_count.is_some() {
+                    return Err(io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        "Duplicate HID_ReportCount",
+                    ));
+                }
+                out_rpt_count = last_rpt_count;
+                last_rpt_count = None;
+            }
+            _ => {}
+        }
+    }
+
+    match (in_rpt_count, out_rpt_count) {
+        (Some(in_count), Some(out_count)) => {
+            if in_count > INIT_HEADER_SIZE
+                && in_count <= MAX_HID_RPT_SIZE
+                && out_count > INIT_HEADER_SIZE
+                && out_count <= MAX_HID_RPT_SIZE
+            {
+                Ok((in_count, out_count))
+            } else {
+                Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "Report size is too small or too large",
+                ))
+            }
+        }
+        _ => Err(io::Error::new(
+            io::ErrorKind::InvalidData,
+            "Failed to extract report sizes from report descriptor",
+        )),
+    }
+}