diff options
Diffstat (limited to 'vendor/object/src/read/macho/dyld_cache.rs')
| -rw-r--r-- | vendor/object/src/read/macho/dyld_cache.rs | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/vendor/object/src/read/macho/dyld_cache.rs b/vendor/object/src/read/macho/dyld_cache.rs new file mode 100644 index 0000000..0f5dfc5 --- /dev/null +++ b/vendor/object/src/read/macho/dyld_cache.rs @@ -0,0 +1,344 @@ +use alloc::vec::Vec; +use core::slice; + +use crate::read::{Error, File, ReadError, ReadRef, Result}; +use crate::{macho, Architecture, Endian, Endianness}; + +/// A parsed representation of the dyld shared cache. +#[derive(Debug)] +pub struct DyldCache<'data, E = Endianness, R = &'data [u8]> +where + E: Endian, + R: ReadRef<'data>, +{ + endian: E, + data: R, + subcaches: Vec<DyldSubCache<'data, E, R>>, + mappings: &'data [macho::DyldCacheMappingInfo<E>], + images: &'data [macho::DyldCacheImageInfo<E>], + arch: Architecture, +} + +/// Information about a subcache. +#[derive(Debug)] +pub struct DyldSubCache<'data, E = Endianness, R = &'data [u8]> +where + E: Endian, + R: ReadRef<'data>, +{ + data: R, + mappings: &'data [macho::DyldCacheMappingInfo<E>], +} + +// This is the offset of the images_across_all_subcaches_count field. +const MIN_HEADER_SIZE_SUBCACHES: u32 = 0x1c4; + +impl<'data, E, R> DyldCache<'data, E, R> +where + E: Endian, + R: ReadRef<'data>, +{ + /// Parse the raw dyld shared cache data. + /// + /// For shared caches from macOS 12 / iOS 15 and above, the subcache files need to be + /// supplied as well, in the correct order, with the `.symbols` subcache last (if present). + /// For example, `data` would be the data for `dyld_shared_cache_x86_64`, + /// and `subcache_data` would be the data for `[dyld_shared_cache_x86_64.1, dyld_shared_cache_x86_64.2, ...]`. + pub fn parse(data: R, subcache_data: &[R]) -> Result<Self> { + let header = macho::DyldCacheHeader::parse(data)?; + let (arch, endian) = header.parse_magic()?; + let mappings = header.mappings(endian, data)?; + + let symbols_subcache_uuid = header.symbols_subcache_uuid(endian); + let subcaches_info = header.subcaches(endian, data)?.unwrap_or(&[]); + + if subcache_data.len() != subcaches_info.len() + symbols_subcache_uuid.is_some() as usize { + return Err(Error("Incorrect number of SubCaches")); + } + + // Split out the .symbols subcache data from the other subcaches. + let (symbols_subcache_data_and_uuid, subcache_data) = + if let Some(symbols_uuid) = symbols_subcache_uuid { + let (sym_data, rest_data) = subcache_data.split_last().unwrap(); + (Some((*sym_data, symbols_uuid)), rest_data) + } else { + (None, subcache_data) + }; + + // Read the regular SubCaches (.1, .2, ...), if present. + let mut subcaches = Vec::new(); + for (&data, info) in subcache_data.iter().zip(subcaches_info.iter()) { + let sc_header = macho::DyldCacheHeader::<E>::parse(data)?; + if sc_header.uuid != info.uuid { + return Err(Error("Unexpected SubCache UUID")); + } + let mappings = sc_header.mappings(endian, data)?; + subcaches.push(DyldSubCache { data, mappings }); + } + + // Read the .symbols SubCache, if present. + // Other than the UUID verification, the symbols SubCache is currently unused. + let _symbols_subcache = match symbols_subcache_data_and_uuid { + Some((data, uuid)) => { + let sc_header = macho::DyldCacheHeader::<E>::parse(data)?; + if sc_header.uuid != uuid { + return Err(Error("Unexpected .symbols SubCache UUID")); + } + let mappings = sc_header.mappings(endian, data)?; + Some(DyldSubCache { data, mappings }) + } + None => None, + }; + + let images = header.images(endian, data)?; + Ok(DyldCache { + endian, + data, + subcaches, + mappings, + images, + arch, + }) + } + + /// Get the architecture type of the file. + pub fn architecture(&self) -> Architecture { + self.arch + } + + /// Get the endianness of the file. + #[inline] + pub fn endianness(&self) -> Endianness { + if self.is_little_endian() { + Endianness::Little + } else { + Endianness::Big + } + } + + /// Return true if the file is little endian, false if it is big endian. + pub fn is_little_endian(&self) -> bool { + self.endian.is_little_endian() + } + + /// Iterate over the images in this cache. + pub fn images<'cache>(&'cache self) -> DyldCacheImageIterator<'data, 'cache, E, R> { + DyldCacheImageIterator { + cache: self, + iter: self.images.iter(), + } + } + + /// Find the address in a mapping and return the cache or subcache data it was found in, + /// together with the translated file offset. + pub fn data_and_offset_for_address(&self, address: u64) -> Option<(R, u64)> { + if let Some(file_offset) = address_to_file_offset(address, self.endian, self.mappings) { + return Some((self.data, file_offset)); + } + for subcache in &self.subcaches { + if let Some(file_offset) = + address_to_file_offset(address, self.endian, subcache.mappings) + { + return Some((subcache.data, file_offset)); + } + } + None + } +} + +/// An iterator over all the images (dylibs) in the dyld shared cache. +#[derive(Debug)] +pub struct DyldCacheImageIterator<'data, 'cache, E = Endianness, R = &'data [u8]> +where + E: Endian, + R: ReadRef<'data>, +{ + cache: &'cache DyldCache<'data, E, R>, + iter: slice::Iter<'data, macho::DyldCacheImageInfo<E>>, +} + +impl<'data, 'cache, E, R> Iterator for DyldCacheImageIterator<'data, 'cache, E, R> +where + E: Endian, + R: ReadRef<'data>, +{ + type Item = DyldCacheImage<'data, 'cache, E, R>; + + fn next(&mut self) -> Option<DyldCacheImage<'data, 'cache, E, R>> { + let image_info = self.iter.next()?; + Some(DyldCacheImage { + cache: self.cache, + image_info, + }) + } +} + +/// One image (dylib) from inside the dyld shared cache. +#[derive(Debug)] +pub struct DyldCacheImage<'data, 'cache, E = Endianness, R = &'data [u8]> +where + E: Endian, + R: ReadRef<'data>, +{ + pub(crate) cache: &'cache DyldCache<'data, E, R>, + image_info: &'data macho::DyldCacheImageInfo<E>, +} + +impl<'data, 'cache, E, R> DyldCacheImage<'data, 'cache, E, R> +where + E: Endian, + R: ReadRef<'data>, +{ + /// The file system path of this image. + pub fn path(&self) -> Result<&'data str> { + let path = self.image_info.path(self.cache.endian, self.cache.data)?; + // The path should always be ascii, so from_utf8 should always succeed. + let path = core::str::from_utf8(path).map_err(|_| Error("Path string not valid utf-8"))?; + Ok(path) + } + + /// The subcache data which contains the Mach-O header for this image, + /// together with the file offset at which this image starts. + pub fn image_data_and_offset(&self) -> Result<(R, u64)> { + let address = self.image_info.address.get(self.cache.endian); + self.cache + .data_and_offset_for_address(address) + .ok_or(Error("Address not found in any mapping")) + } + + /// Parse this image into an Object. + pub fn parse_object(&self) -> Result<File<'data, R>> { + File::parse_dyld_cache_image(self) + } +} + +impl<E: Endian> macho::DyldCacheHeader<E> { + /// Read the dyld cache header. + pub fn parse<'data, R: ReadRef<'data>>(data: R) -> Result<&'data Self> { + data.read_at::<macho::DyldCacheHeader<E>>(0) + .read_error("Invalid dyld cache header size or alignment") + } + + /// Returns (arch, endian) based on the magic string. + pub fn parse_magic(&self) -> Result<(Architecture, E)> { + let (arch, is_big_endian) = match &self.magic { + b"dyld_v1 i386\0" => (Architecture::I386, false), + b"dyld_v1 x86_64\0" => (Architecture::X86_64, false), + b"dyld_v1 x86_64h\0" => (Architecture::X86_64, false), + b"dyld_v1 ppc\0" => (Architecture::PowerPc, true), + b"dyld_v1 armv6\0" => (Architecture::Arm, false), + b"dyld_v1 armv7\0" => (Architecture::Arm, false), + b"dyld_v1 armv7f\0" => (Architecture::Arm, false), + b"dyld_v1 armv7s\0" => (Architecture::Arm, false), + b"dyld_v1 armv7k\0" => (Architecture::Arm, false), + b"dyld_v1 arm64\0" => (Architecture::Aarch64, false), + b"dyld_v1 arm64e\0" => (Architecture::Aarch64, false), + _ => return Err(Error("Unrecognized dyld cache magic")), + }; + let endian = + E::from_big_endian(is_big_endian).read_error("Unsupported dyld cache endian")?; + Ok((arch, endian)) + } + + /// Return the mapping information table. + pub fn mappings<'data, R: ReadRef<'data>>( + &self, + endian: E, + data: R, + ) -> Result<&'data [macho::DyldCacheMappingInfo<E>]> { + data.read_slice_at::<macho::DyldCacheMappingInfo<E>>( + self.mapping_offset.get(endian).into(), + self.mapping_count.get(endian) as usize, + ) + .read_error("Invalid dyld cache mapping size or alignment") + } + + /// Return the information about subcaches, if present. + pub fn subcaches<'data, R: ReadRef<'data>>( + &self, + endian: E, + data: R, + ) -> Result<Option<&'data [macho::DyldSubCacheInfo<E>]>> { + if self.mapping_offset.get(endian) >= MIN_HEADER_SIZE_SUBCACHES { + let subcaches = data + .read_slice_at::<macho::DyldSubCacheInfo<E>>( + self.subcaches_offset.get(endian).into(), + self.subcaches_count.get(endian) as usize, + ) + .read_error("Invalid dyld subcaches size or alignment")?; + Ok(Some(subcaches)) + } else { + Ok(None) + } + } + + /// Return the UUID for the .symbols subcache, if present. + pub fn symbols_subcache_uuid(&self, endian: E) -> Option<[u8; 16]> { + if self.mapping_offset.get(endian) >= MIN_HEADER_SIZE_SUBCACHES { + let uuid = self.symbols_subcache_uuid; + if uuid != [0; 16] { + return Some(uuid); + } + } + None + } + + /// Return the image information table. + pub fn images<'data, R: ReadRef<'data>>( + &self, + endian: E, + data: R, + ) -> Result<&'data [macho::DyldCacheImageInfo<E>]> { + if self.mapping_offset.get(endian) >= MIN_HEADER_SIZE_SUBCACHES { + data.read_slice_at::<macho::DyldCacheImageInfo<E>>( + self.images_across_all_subcaches_offset.get(endian).into(), + self.images_across_all_subcaches_count.get(endian) as usize, + ) + .read_error("Invalid dyld cache image size or alignment") + } else { + data.read_slice_at::<macho::DyldCacheImageInfo<E>>( + self.images_offset.get(endian).into(), + self.images_count.get(endian) as usize, + ) + .read_error("Invalid dyld cache image size or alignment") + } + } +} + +impl<E: Endian> macho::DyldCacheImageInfo<E> { + /// The file system path of this image. + pub fn path<'data, R: ReadRef<'data>>(&self, endian: E, data: R) -> Result<&'data [u8]> { + let r_start = self.path_file_offset.get(endian).into(); + let r_end = data.len().read_error("Couldn't get data len()")?; + data.read_bytes_at_until(r_start..r_end, 0) + .read_error("Couldn't read dyld cache image path") + } + + /// Find the file offset of the image by looking up its address in the mappings. + pub fn file_offset( + &self, + endian: E, + mappings: &[macho::DyldCacheMappingInfo<E>], + ) -> Result<u64> { + let address = self.address.get(endian); + address_to_file_offset(address, endian, mappings) + .read_error("Invalid dyld cache image address") + } +} + +/// Find the file offset of the image by looking up its address in the mappings. +pub fn address_to_file_offset<E: Endian>( + address: u64, + endian: E, + mappings: &[macho::DyldCacheMappingInfo<E>], +) -> Option<u64> { + for mapping in mappings { + let mapping_address = mapping.address.get(endian); + if address >= mapping_address + && address < mapping_address.wrapping_add(mapping.size.get(endian)) + { + return Some(address - mapping_address + mapping.file_offset.get(endian)); + } + } + None +} |