summaryrefslogtreecommitdiffstats
path: root/third_party/rust/object/src/read/coff/section.rs
diff options
context:
space:
mode:
Diffstat (limited to 'third_party/rust/object/src/read/coff/section.rs')
-rw-r--r--third_party/rust/object/src/read/coff/section.rs524
1 files changed, 524 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/coff/section.rs b/third_party/rust/object/src/read/coff/section.rs
new file mode 100644
index 0000000000..731e37ca8b
--- /dev/null
+++ b/third_party/rust/object/src/read/coff/section.rs
@@ -0,0 +1,524 @@
+use core::convert::TryFrom;
+use core::{iter, result, slice, str};
+
+use crate::endian::LittleEndian as LE;
+use crate::pe;
+use crate::read::util::StringTable;
+use crate::read::{
+ self, CompressedData, CompressedFileRange, Error, ObjectSection, ObjectSegment, ReadError,
+ ReadRef, Result, SectionFlags, SectionIndex, SectionKind, SegmentFlags,
+};
+
+use super::{CoffFile, CoffRelocationIterator};
+
+/// The table of section headers in a COFF or PE file.
+#[derive(Debug, Default, Clone, Copy)]
+pub struct SectionTable<'data> {
+ sections: &'data [pe::ImageSectionHeader],
+}
+
+impl<'data> SectionTable<'data> {
+ /// Parse the section table.
+ ///
+ /// `data` must be the entire file data.
+ /// `offset` must be after the optional file header.
+ pub fn parse<R: ReadRef<'data>>(
+ header: &pe::ImageFileHeader,
+ data: R,
+ offset: u64,
+ ) -> Result<Self> {
+ let sections = data
+ .read_slice_at(offset, header.number_of_sections.get(LE).into())
+ .read_error("Invalid COFF/PE section headers")?;
+ Ok(SectionTable { sections })
+ }
+
+ /// Iterate over the section headers.
+ ///
+ /// Warning: sections indices start at 1.
+ #[inline]
+ pub fn iter(&self) -> slice::Iter<'data, pe::ImageSectionHeader> {
+ self.sections.iter()
+ }
+
+ /// Return true if the section table is empty.
+ #[inline]
+ pub fn is_empty(&self) -> bool {
+ self.sections.is_empty()
+ }
+
+ /// The number of section headers.
+ #[inline]
+ pub fn len(&self) -> usize {
+ self.sections.len()
+ }
+
+ /// Return the section header at the given index.
+ ///
+ /// The index is 1-based.
+ pub fn section(&self, index: usize) -> read::Result<&'data pe::ImageSectionHeader> {
+ self.sections
+ .get(index.wrapping_sub(1))
+ .read_error("Invalid COFF/PE section index")
+ }
+
+ /// Return the section header with the given name.
+ ///
+ /// The returned index is 1-based.
+ ///
+ /// Ignores sections with invalid names.
+ pub fn section_by_name<R: ReadRef<'data>>(
+ &self,
+ strings: StringTable<'data, R>,
+ name: &[u8],
+ ) -> Option<(usize, &'data pe::ImageSectionHeader)> {
+ self.sections
+ .iter()
+ .enumerate()
+ .find(|(_, section)| section.name(strings) == Ok(name))
+ .map(|(index, section)| (index + 1, section))
+ }
+
+ /// Compute the maximum file offset used by sections.
+ ///
+ /// This will usually match the end of file, unless the PE file has a
+ /// [data overlay](https://security.stackexchange.com/questions/77336/how-is-the-file-overlay-read-by-an-exe-virus)
+ pub fn max_section_file_offset(&self) -> u64 {
+ let mut max = 0;
+ for section in self.iter() {
+ match (section.pointer_to_raw_data.get(LE) as u64)
+ .checked_add(section.size_of_raw_data.get(LE) as u64)
+ {
+ None => {
+ // This cannot happen, we're suming two u32 into a u64
+ continue;
+ }
+ Some(end_of_section) => {
+ if end_of_section > max {
+ max = end_of_section;
+ }
+ }
+ }
+ }
+ max
+ }
+}
+
+/// An iterator over the loadable sections of a `CoffFile`.
+#[derive(Debug)]
+pub struct CoffSegmentIterator<'data, 'file, R: ReadRef<'data> = &'data [u8]> {
+ pub(super) file: &'file CoffFile<'data, R>,
+ pub(super) iter: slice::Iter<'data, pe::ImageSectionHeader>,
+}
+
+impl<'data, 'file, R: ReadRef<'data>> Iterator for CoffSegmentIterator<'data, 'file, R> {
+ type Item = CoffSegment<'data, 'file, R>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter.next().map(|section| CoffSegment {
+ file: self.file,
+ section,
+ })
+ }
+}
+
+/// A loadable section of a `CoffFile`.
+#[derive(Debug)]
+pub struct CoffSegment<'data, 'file, R: ReadRef<'data> = &'data [u8]> {
+ pub(super) file: &'file CoffFile<'data, R>,
+ pub(super) section: &'data pe::ImageSectionHeader,
+}
+
+impl<'data, 'file, R: ReadRef<'data>> CoffSegment<'data, 'file, R> {
+ fn bytes(&self) -> Result<&'data [u8]> {
+ self.section
+ .coff_data(self.file.data)
+ .read_error("Invalid COFF section offset or size")
+ }
+}
+
+impl<'data, 'file, R: ReadRef<'data>> read::private::Sealed for CoffSegment<'data, 'file, R> {}
+
+impl<'data, 'file, R: ReadRef<'data>> ObjectSegment<'data> for CoffSegment<'data, 'file, R> {
+ #[inline]
+ fn address(&self) -> u64 {
+ u64::from(self.section.virtual_address.get(LE))
+ }
+
+ #[inline]
+ fn size(&self) -> u64 {
+ u64::from(self.section.virtual_size.get(LE))
+ }
+
+ #[inline]
+ fn align(&self) -> u64 {
+ self.section.coff_alignment()
+ }
+
+ #[inline]
+ fn file_range(&self) -> (u64, u64) {
+ let (offset, size) = self.section.coff_file_range().unwrap_or((0, 0));
+ (u64::from(offset), u64::from(size))
+ }
+
+ fn data(&self) -> Result<&'data [u8]> {
+ self.bytes()
+ }
+
+ fn data_range(&self, address: u64, size: u64) -> Result<Option<&'data [u8]>> {
+ Ok(read::util::data_range(
+ self.bytes()?,
+ self.address(),
+ address,
+ size,
+ ))
+ }
+
+ #[inline]
+ fn name_bytes(&self) -> Result<Option<&[u8]>> {
+ self.section
+ .name(self.file.common.symbols.strings())
+ .map(Some)
+ }
+
+ #[inline]
+ fn name(&self) -> Result<Option<&str>> {
+ let name = self.section.name(self.file.common.symbols.strings())?;
+ str::from_utf8(name)
+ .ok()
+ .read_error("Non UTF-8 COFF section name")
+ .map(Some)
+ }
+
+ #[inline]
+ fn flags(&self) -> SegmentFlags {
+ let characteristics = self.section.characteristics.get(LE);
+ SegmentFlags::Coff { characteristics }
+ }
+}
+
+/// An iterator over the sections of a `CoffFile`.
+#[derive(Debug)]
+pub struct CoffSectionIterator<'data, 'file, R: ReadRef<'data> = &'data [u8]> {
+ pub(super) file: &'file CoffFile<'data, R>,
+ pub(super) iter: iter::Enumerate<slice::Iter<'data, pe::ImageSectionHeader>>,
+}
+
+impl<'data, 'file, R: ReadRef<'data>> Iterator for CoffSectionIterator<'data, 'file, R> {
+ type Item = CoffSection<'data, 'file, R>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter.next().map(|(index, section)| CoffSection {
+ file: self.file,
+ index: SectionIndex(index + 1),
+ section,
+ })
+ }
+}
+
+/// A section of a `CoffFile`.
+#[derive(Debug)]
+pub struct CoffSection<'data, 'file, R: ReadRef<'data> = &'data [u8]> {
+ pub(super) file: &'file CoffFile<'data, R>,
+ pub(super) index: SectionIndex,
+ pub(super) section: &'data pe::ImageSectionHeader,
+}
+
+impl<'data, 'file, R: ReadRef<'data>> CoffSection<'data, 'file, R> {
+ fn bytes(&self) -> Result<&'data [u8]> {
+ self.section
+ .coff_data(self.file.data)
+ .read_error("Invalid COFF section offset or size")
+ }
+}
+
+impl<'data, 'file, R: ReadRef<'data>> read::private::Sealed for CoffSection<'data, 'file, R> {}
+
+impl<'data, 'file, R: ReadRef<'data>> ObjectSection<'data> for CoffSection<'data, 'file, R> {
+ type RelocationIterator = CoffRelocationIterator<'data, 'file, R>;
+
+ #[inline]
+ fn index(&self) -> SectionIndex {
+ self.index
+ }
+
+ #[inline]
+ fn address(&self) -> u64 {
+ u64::from(self.section.virtual_address.get(LE))
+ }
+
+ #[inline]
+ fn size(&self) -> u64 {
+ // TODO: This may need to be the length from the auxiliary symbol for this section.
+ u64::from(self.section.size_of_raw_data.get(LE))
+ }
+
+ #[inline]
+ fn align(&self) -> u64 {
+ self.section.coff_alignment()
+ }
+
+ #[inline]
+ fn file_range(&self) -> Option<(u64, u64)> {
+ let (offset, size) = self.section.coff_file_range()?;
+ Some((u64::from(offset), u64::from(size)))
+ }
+
+ fn data(&self) -> Result<&'data [u8]> {
+ self.bytes()
+ }
+
+ fn data_range(&self, address: u64, size: u64) -> Result<Option<&'data [u8]>> {
+ Ok(read::util::data_range(
+ self.bytes()?,
+ self.address(),
+ address,
+ size,
+ ))
+ }
+
+ #[inline]
+ fn compressed_file_range(&self) -> Result<CompressedFileRange> {
+ Ok(CompressedFileRange::none(self.file_range()))
+ }
+
+ #[inline]
+ fn compressed_data(&self) -> Result<CompressedData<'data>> {
+ self.data().map(CompressedData::none)
+ }
+
+ #[inline]
+ fn name_bytes(&self) -> Result<&[u8]> {
+ self.section.name(self.file.common.symbols.strings())
+ }
+
+ #[inline]
+ fn name(&self) -> Result<&str> {
+ let name = self.name_bytes()?;
+ str::from_utf8(name)
+ .ok()
+ .read_error("Non UTF-8 COFF section name")
+ }
+
+ #[inline]
+ fn segment_name_bytes(&self) -> Result<Option<&[u8]>> {
+ Ok(None)
+ }
+
+ #[inline]
+ fn segment_name(&self) -> Result<Option<&str>> {
+ Ok(None)
+ }
+
+ #[inline]
+ fn kind(&self) -> SectionKind {
+ self.section.kind()
+ }
+
+ fn relocations(&self) -> CoffRelocationIterator<'data, 'file, R> {
+ let relocations = self.section.coff_relocations(self.file.data).unwrap_or(&[]);
+ CoffRelocationIterator {
+ file: self.file,
+ iter: relocations.iter(),
+ }
+ }
+
+ fn flags(&self) -> SectionFlags {
+ SectionFlags::Coff {
+ characteristics: self.section.characteristics.get(LE),
+ }
+ }
+}
+
+impl pe::ImageSectionHeader {
+ pub(crate) fn kind(&self) -> SectionKind {
+ let characteristics = self.characteristics.get(LE);
+ if characteristics & (pe::IMAGE_SCN_CNT_CODE | pe::IMAGE_SCN_MEM_EXECUTE) != 0 {
+ SectionKind::Text
+ } else if characteristics & pe::IMAGE_SCN_CNT_INITIALIZED_DATA != 0 {
+ if characteristics & pe::IMAGE_SCN_MEM_DISCARDABLE != 0 {
+ SectionKind::Other
+ } else if characteristics & pe::IMAGE_SCN_MEM_WRITE != 0 {
+ SectionKind::Data
+ } else {
+ SectionKind::ReadOnlyData
+ }
+ } else if characteristics & pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA != 0 {
+ SectionKind::UninitializedData
+ } else if characteristics & pe::IMAGE_SCN_LNK_INFO != 0 {
+ SectionKind::Linker
+ } else {
+ SectionKind::Unknown
+ }
+ }
+}
+
+impl pe::ImageSectionHeader {
+ /// Return the string table offset of the section name.
+ ///
+ /// Returns `Ok(None)` if the name doesn't use the string table
+ /// and can be obtained with `raw_name` instead.
+ pub fn name_offset(&self) -> Result<Option<u32>> {
+ let bytes = &self.name;
+ if bytes[0] != b'/' {
+ return Ok(None);
+ }
+
+ if bytes[1] == b'/' {
+ let mut offset = 0;
+ for byte in bytes[2..].iter() {
+ let digit = match byte {
+ b'A'..=b'Z' => byte - b'A',
+ b'a'..=b'z' => byte - b'a' + 26,
+ b'0'..=b'9' => byte - b'0' + 52,
+ b'+' => 62,
+ b'/' => 63,
+ _ => return Err(Error("Invalid COFF section name base-64 offset")),
+ };
+ offset = offset * 64 + digit as u64;
+ }
+ u32::try_from(offset)
+ .ok()
+ .read_error("Invalid COFF section name base-64 offset")
+ .map(Some)
+ } else {
+ let mut offset = 0;
+ for byte in bytes[1..].iter() {
+ let digit = match byte {
+ b'0'..=b'9' => byte - b'0',
+ 0 => break,
+ _ => return Err(Error("Invalid COFF section name base-10 offset")),
+ };
+ offset = offset * 10 + digit as u32;
+ }
+ Ok(Some(offset))
+ }
+ }
+
+ /// Return the section name.
+ ///
+ /// This handles decoding names that are offsets into the symbol string table.
+ pub fn name<'data, R: ReadRef<'data>>(
+ &'data self,
+ strings: StringTable<'data, R>,
+ ) -> Result<&'data [u8]> {
+ if let Some(offset) = self.name_offset()? {
+ strings
+ .get(offset)
+ .read_error("Invalid COFF section name offset")
+ } else {
+ Ok(self.raw_name())
+ }
+ }
+
+ /// Return the raw section name.
+ pub fn raw_name(&self) -> &[u8] {
+ let bytes = &self.name;
+ match memchr::memchr(b'\0', bytes) {
+ Some(end) => &bytes[..end],
+ None => &bytes[..],
+ }
+ }
+
+ /// Return the offset and size of the section in a COFF file.
+ ///
+ /// Returns `None` for sections that have no data in the file.
+ pub fn coff_file_range(&self) -> Option<(u32, u32)> {
+ if self.characteristics.get(LE) & pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA != 0 {
+ None
+ } else {
+ let offset = self.pointer_to_raw_data.get(LE);
+ // Note: virtual size is not used for COFF.
+ let size = self.size_of_raw_data.get(LE);
+ Some((offset, size))
+ }
+ }
+
+ /// Return the section data in a COFF file.
+ ///
+ /// Returns `Ok(&[])` if the section has no data.
+ /// Returns `Err` for invalid values.
+ pub fn coff_data<'data, R: ReadRef<'data>>(&self, data: R) -> result::Result<&'data [u8], ()> {
+ if let Some((offset, size)) = self.coff_file_range() {
+ data.read_bytes_at(offset.into(), size.into())
+ } else {
+ Ok(&[])
+ }
+ }
+
+ /// Return the section alignment in bytes.
+ ///
+ /// This is only valid for sections in a COFF file.
+ pub fn coff_alignment(&self) -> u64 {
+ match self.characteristics.get(LE) & pe::IMAGE_SCN_ALIGN_MASK {
+ pe::IMAGE_SCN_ALIGN_1BYTES => 1,
+ pe::IMAGE_SCN_ALIGN_2BYTES => 2,
+ pe::IMAGE_SCN_ALIGN_4BYTES => 4,
+ pe::IMAGE_SCN_ALIGN_8BYTES => 8,
+ pe::IMAGE_SCN_ALIGN_16BYTES => 16,
+ pe::IMAGE_SCN_ALIGN_32BYTES => 32,
+ pe::IMAGE_SCN_ALIGN_64BYTES => 64,
+ pe::IMAGE_SCN_ALIGN_128BYTES => 128,
+ pe::IMAGE_SCN_ALIGN_256BYTES => 256,
+ pe::IMAGE_SCN_ALIGN_512BYTES => 512,
+ pe::IMAGE_SCN_ALIGN_1024BYTES => 1024,
+ pe::IMAGE_SCN_ALIGN_2048BYTES => 2048,
+ pe::IMAGE_SCN_ALIGN_4096BYTES => 4096,
+ pe::IMAGE_SCN_ALIGN_8192BYTES => 8192,
+ _ => 16,
+ }
+ }
+
+ /// Read the relocations in a COFF file.
+ ///
+ /// `data` must be the entire file data.
+ pub fn coff_relocations<'data, R: ReadRef<'data>>(
+ &self,
+ data: R,
+ ) -> read::Result<&'data [pe::ImageRelocation]> {
+ let mut pointer = self.pointer_to_relocations.get(LE).into();
+ let mut number: usize = self.number_of_relocations.get(LE).into();
+ if number == core::u16::MAX.into()
+ && self.characteristics.get(LE) & pe::IMAGE_SCN_LNK_NRELOC_OVFL != 0
+ {
+ // Extended relocations. Read first relocation (which contains extended count) & adjust
+ // relocations pointer.
+ let extended_relocation_info = data
+ .read_at::<pe::ImageRelocation>(pointer)
+ .read_error("Invalid COFF relocation offset or number")?;
+ number = extended_relocation_info.virtual_address.get(LE) as usize;
+ if number == 0 {
+ return Err(Error("Invalid COFF relocation number"));
+ }
+ pointer += core::mem::size_of::<pe::ImageRelocation>() as u64;
+ // Extended relocation info does not contribute to the count of sections.
+ number -= 1;
+ }
+ data.read_slice_at(pointer, number)
+ .read_error("Invalid COFF relocation offset or number")
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn name_offset() {
+ let mut section = pe::ImageSectionHeader::default();
+ section.name = *b"xxxxxxxx";
+ assert_eq!(section.name_offset(), Ok(None));
+ section.name = *b"/0\0\0\0\0\0\0";
+ assert_eq!(section.name_offset(), Ok(Some(0)));
+ section.name = *b"/9999999";
+ assert_eq!(section.name_offset(), Ok(Some(999_9999)));
+ section.name = *b"//AAAAAA";
+ assert_eq!(section.name_offset(), Ok(Some(0)));
+ section.name = *b"//D/////";
+ assert_eq!(section.name_offset(), Ok(Some(0xffff_ffff)));
+ section.name = *b"//EAAAAA";
+ assert!(section.name_offset().is_err());
+ section.name = *b"////////";
+ assert!(section.name_offset().is_err());
+ }
+}