diff options
Diffstat (limited to 'vendor/object-0.29.0/src/read/coff/section.rs')
| -rw-r--r-- | vendor/object-0.29.0/src/read/coff/section.rs | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/vendor/object-0.29.0/src/read/coff/section.rs b/vendor/object-0.29.0/src/read/coff/section.rs new file mode 100644 index 000000000..731e37ca8 --- /dev/null +++ b/vendor/object-0.29.0/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()); + } +} |