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-rw-r--r--vendor/object/src/read/pe/rich.rs91
1 files changed, 91 insertions, 0 deletions
diff --git a/vendor/object/src/read/pe/rich.rs b/vendor/object/src/read/pe/rich.rs
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+//! PE rich header handling
+
+use core::mem;
+
+use crate::pod::bytes_of_slice;
+use crate::read::Bytes;
+use crate::{pe, LittleEndian as LE, ReadRef, U32};
+
+/// Parsed information about a Rich Header.
+#[derive(Debug, Clone, Copy)]
+pub struct RichHeaderInfo<'data> {
+ /// The offset at which the rich header starts.
+ pub offset: usize,
+ /// The length (in bytes) of the rich header.
+ ///
+ /// This includes the payload, but also the 16-byte start sequence and the
+ /// 8-byte final "Rich" and XOR key.
+ pub length: usize,
+ /// The XOR key used to mask the rich header.
+ ///
+ /// Unless the file has been tampered with, it should be equal to a checksum
+ /// of the file header.
+ pub xor_key: u32,
+ masked_entries: &'data [pe::MaskedRichHeaderEntry],
+}
+
+/// A PE rich header entry after it has been unmasked.
+///
+/// See [`pe::MaskedRichHeaderEntry`].
+#[derive(Debug, Clone, Copy)]
+#[repr(C)]
+pub struct RichHeaderEntry {
+ /// ID of the component.
+ pub comp_id: u32,
+ /// Number of times this component has been used when building this PE.
+ pub count: u32,
+}
+
+impl<'data> RichHeaderInfo<'data> {
+ /// Try to locate a rich header and its entries in the current PE file.
+ pub fn parse<R: ReadRef<'data>>(data: R, nt_header_offset: u64) -> Option<Self> {
+ // Locate the rich header, if any.
+ // It ends with the "Rich" string and an XOR key, before the NT header.
+ let data = data.read_bytes_at(0, nt_header_offset).map(Bytes).ok()?;
+ let end_marker_offset = memmem(data.0, b"Rich", 4)?;
+ let xor_key = *data.read_at::<U32<LE>>(end_marker_offset + 4).ok()?;
+
+ // It starts at the masked "DanS" string and 3 masked zeroes.
+ let masked_start_marker = U32::new(LE, 0x536e_6144 ^ xor_key.get(LE));
+ let start_header = [masked_start_marker, xor_key, xor_key, xor_key];
+ let start_sequence = bytes_of_slice(&start_header);
+ let start_marker_offset = memmem(&data.0[..end_marker_offset], start_sequence, 4)?;
+
+ // Extract the items between the markers.
+ let items_offset = start_marker_offset + start_sequence.len();
+ let items_len = end_marker_offset - items_offset;
+ let item_count = items_len / mem::size_of::<pe::MaskedRichHeaderEntry>();
+ let items = data.read_slice_at(items_offset, item_count).ok()?;
+ Some(RichHeaderInfo {
+ offset: start_marker_offset,
+ // Includes "Rich" marker and the XOR key.
+ length: end_marker_offset - start_marker_offset + 8,
+ xor_key: xor_key.get(LE),
+ masked_entries: items,
+ })
+ }
+
+ /// Returns an iterator over the unmasked entries.
+ pub fn unmasked_entries(&self) -> impl Iterator<Item = RichHeaderEntry> + 'data {
+ let xor_key = self.xor_key;
+ self.masked_entries
+ .iter()
+ .map(move |entry| RichHeaderEntry {
+ comp_id: entry.masked_comp_id.get(LE) ^ xor_key,
+ count: entry.masked_count.get(LE) ^ xor_key,
+ })
+ }
+}
+
+/// Find the offset of the first occurrence of needle in the data.
+///
+/// The offset must have the given alignment.
+fn memmem(data: &[u8], needle: &[u8], align: usize) -> Option<usize> {
+ let mut offset = 0;
+ loop {
+ if data.get(offset..)?.get(..needle.len())? == needle {
+ return Some(offset);
+ }
+ offset += align;
+ }
+}