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Diffstat (limited to 'vendor/object/src/read/elf/relocation.rs')
| -rw-r--r-- | vendor/object/src/read/elf/relocation.rs | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/vendor/object/src/read/elf/relocation.rs b/vendor/object/src/read/elf/relocation.rs new file mode 100644 index 000000000..557b80efc --- /dev/null +++ b/vendor/object/src/read/elf/relocation.rs @@ -0,0 +1,539 @@ +use alloc::fmt; +use alloc::vec::Vec; +use core::fmt::Debug; +use core::slice; + +use crate::elf; +use crate::endian::{self, Endianness}; +use crate::pod::Pod; +use crate::read::{ + self, Error, ReadRef, Relocation, RelocationEncoding, RelocationKind, RelocationTarget, + SectionIndex, SymbolIndex, +}; + +use super::{ElfFile, FileHeader, SectionHeader, SectionTable}; + +/// A mapping from section index to associated relocation sections. +#[derive(Debug)] +pub struct RelocationSections { + relocations: Vec<usize>, +} + +impl RelocationSections { + /// Create a new mapping using the section table. + /// + /// Skips relocation sections that do not use the given symbol table section. + pub fn parse<'data, Elf: FileHeader, R: ReadRef<'data>>( + endian: Elf::Endian, + sections: &SectionTable<'data, Elf, R>, + symbol_section: SectionIndex, + ) -> read::Result<Self> { + let mut relocations = vec![0; sections.len()]; + for (index, section) in sections.iter().enumerate().rev() { + let sh_type = section.sh_type(endian); + if sh_type == elf::SHT_REL || sh_type == elf::SHT_RELA { + // The symbol indices used in relocations must be for the symbol table + // we are expecting to use. + let sh_link = SectionIndex(section.sh_link(endian) as usize); + if sh_link != symbol_section { + continue; + } + + let sh_info = section.sh_info(endian) as usize; + if sh_info == 0 { + // Skip dynamic relocations. + continue; + } + if sh_info >= relocations.len() { + return Err(Error("Invalid ELF sh_info for relocation section")); + } + + // Handle multiple relocation sections by chaining them. + let next = relocations[sh_info]; + relocations[sh_info] = index; + relocations[index] = next; + } + } + Ok(Self { relocations }) + } + + /// Given a section index, return the section index of the associated relocation section. + /// + /// This may also be called with a relocation section index, and it will return the + /// next associated relocation section. + pub fn get(&self, index: usize) -> Option<usize> { + self.relocations.get(index).cloned().filter(|x| *x != 0) + } +} + +pub(super) enum ElfRelaIterator<'data, Elf: FileHeader> { + Rel(slice::Iter<'data, Elf::Rel>), + Rela(slice::Iter<'data, Elf::Rela>), +} + +impl<'data, Elf: FileHeader> ElfRelaIterator<'data, Elf> { + fn is_rel(&self) -> bool { + match self { + ElfRelaIterator::Rel(_) => true, + ElfRelaIterator::Rela(_) => false, + } + } +} + +impl<'data, Elf: FileHeader> Iterator for ElfRelaIterator<'data, Elf> { + type Item = Elf::Rela; + + fn next(&mut self) -> Option<Self::Item> { + match self { + ElfRelaIterator::Rel(ref mut i) => i.next().cloned().map(Self::Item::from), + ElfRelaIterator::Rela(ref mut i) => i.next().cloned(), + } + } +} + +/// An iterator over the dynamic relocations for an `ElfFile32`. +pub type ElfDynamicRelocationIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> = + ElfDynamicRelocationIterator<'data, 'file, elf::FileHeader32<Endian>, R>; +/// An iterator over the dynamic relocations for an `ElfFile64`. +pub type ElfDynamicRelocationIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> = + ElfDynamicRelocationIterator<'data, 'file, elf::FileHeader64<Endian>, R>; + +/// An iterator over the dynamic relocations for an `ElfFile`. +pub struct ElfDynamicRelocationIterator<'data, 'file, Elf, R = &'data [u8]> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + /// The current relocation section index. + pub(super) section_index: SectionIndex, + pub(super) file: &'file ElfFile<'data, Elf, R>, + pub(super) relocations: Option<ElfRelaIterator<'data, Elf>>, +} + +impl<'data, 'file, Elf, R> Iterator for ElfDynamicRelocationIterator<'data, 'file, Elf, R> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + type Item = (u64, Relocation); + + fn next(&mut self) -> Option<Self::Item> { + let endian = self.file.endian; + loop { + if let Some(ref mut relocations) = self.relocations { + if let Some(reloc) = relocations.next() { + let relocation = + parse_relocation(self.file.header, endian, reloc, relocations.is_rel()); + return Some((reloc.r_offset(endian).into(), relocation)); + } + self.relocations = None; + } + + let section = self.file.sections.section(self.section_index).ok()?; + self.section_index.0 += 1; + + let sh_link = SectionIndex(section.sh_link(endian) as usize); + if sh_link != self.file.dynamic_symbols.section() { + continue; + } + + match section.sh_type(endian) { + elf::SHT_REL => { + if let Ok(relocations) = section.data_as_array(endian, self.file.data) { + self.relocations = Some(ElfRelaIterator::Rel(relocations.iter())); + } + } + elf::SHT_RELA => { + if let Ok(relocations) = section.data_as_array(endian, self.file.data) { + self.relocations = Some(ElfRelaIterator::Rela(relocations.iter())); + } + } + _ => {} + } + } + } +} + +impl<'data, 'file, Elf, R> fmt::Debug for ElfDynamicRelocationIterator<'data, 'file, Elf, R> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("ElfDynamicRelocationIterator").finish() + } +} + +/// An iterator over the relocations for an `ElfSection32`. +pub type ElfSectionRelocationIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> = + ElfSectionRelocationIterator<'data, 'file, elf::FileHeader32<Endian>, R>; +/// An iterator over the relocations for an `ElfSection64`. +pub type ElfSectionRelocationIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> = + ElfSectionRelocationIterator<'data, 'file, elf::FileHeader64<Endian>, R>; + +/// An iterator over the relocations for an `ElfSection`. +pub struct ElfSectionRelocationIterator<'data, 'file, Elf, R = &'data [u8]> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + /// The current pointer in the chain of relocation sections. + pub(super) section_index: SectionIndex, + pub(super) file: &'file ElfFile<'data, Elf, R>, + pub(super) relocations: Option<ElfRelaIterator<'data, Elf>>, +} + +impl<'data, 'file, Elf, R> Iterator for ElfSectionRelocationIterator<'data, 'file, Elf, R> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + type Item = (u64, Relocation); + + fn next(&mut self) -> Option<Self::Item> { + let endian = self.file.endian; + loop { + if let Some(ref mut relocations) = self.relocations { + if let Some(reloc) = relocations.next() { + let relocation = + parse_relocation(self.file.header, endian, reloc, relocations.is_rel()); + return Some((reloc.r_offset(endian).into(), relocation)); + } + self.relocations = None; + } + self.section_index = SectionIndex(self.file.relocations.get(self.section_index.0)?); + // The construction of RelocationSections ensures section_index is valid. + let section = self.file.sections.section(self.section_index).unwrap(); + match section.sh_type(endian) { + elf::SHT_REL => { + if let Ok(relocations) = section.data_as_array(endian, self.file.data) { + self.relocations = Some(ElfRelaIterator::Rel(relocations.iter())); + } + } + elf::SHT_RELA => { + if let Ok(relocations) = section.data_as_array(endian, self.file.data) { + self.relocations = Some(ElfRelaIterator::Rela(relocations.iter())); + } + } + _ => {} + } + } + } +} + +impl<'data, 'file, Elf, R> fmt::Debug for ElfSectionRelocationIterator<'data, 'file, Elf, R> +where + Elf: FileHeader, + R: ReadRef<'data>, +{ + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("ElfSectionRelocationIterator").finish() + } +} + +fn parse_relocation<Elf: FileHeader>( + header: &Elf, + endian: Elf::Endian, + reloc: Elf::Rela, + implicit_addend: bool, +) -> Relocation { + let mut encoding = RelocationEncoding::Generic; + let is_mips64el = header.is_mips64el(endian); + let (kind, size) = match header.e_machine(endian) { + elf::EM_AARCH64 => match reloc.r_type(endian, false) { + elf::R_AARCH64_ABS64 => (RelocationKind::Absolute, 64), + elf::R_AARCH64_ABS32 => (RelocationKind::Absolute, 32), + elf::R_AARCH64_ABS16 => (RelocationKind::Absolute, 16), + elf::R_AARCH64_PREL64 => (RelocationKind::Relative, 64), + elf::R_AARCH64_PREL32 => (RelocationKind::Relative, 32), + elf::R_AARCH64_PREL16 => (RelocationKind::Relative, 16), + elf::R_AARCH64_CALL26 => { + encoding = RelocationEncoding::AArch64Call; + (RelocationKind::PltRelative, 26) + } + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_ARM => match reloc.r_type(endian, false) { + elf::R_ARM_ABS32 => (RelocationKind::Absolute, 32), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_AVR => match reloc.r_type(endian, false) { + elf::R_AVR_32 => (RelocationKind::Absolute, 32), + elf::R_AVR_16 => (RelocationKind::Absolute, 16), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_BPF => match reloc.r_type(endian, false) { + elf::R_BPF_64_64 => (RelocationKind::Absolute, 64), + elf::R_BPF_64_32 => (RelocationKind::Absolute, 32), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_386 => match reloc.r_type(endian, false) { + elf::R_386_32 => (RelocationKind::Absolute, 32), + elf::R_386_PC32 => (RelocationKind::Relative, 32), + elf::R_386_GOT32 => (RelocationKind::Got, 32), + elf::R_386_PLT32 => (RelocationKind::PltRelative, 32), + elf::R_386_GOTOFF => (RelocationKind::GotBaseOffset, 32), + elf::R_386_GOTPC => (RelocationKind::GotBaseRelative, 32), + elf::R_386_16 => (RelocationKind::Absolute, 16), + elf::R_386_PC16 => (RelocationKind::Relative, 16), + elf::R_386_8 => (RelocationKind::Absolute, 8), + elf::R_386_PC8 => (RelocationKind::Relative, 8), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_X86_64 => match reloc.r_type(endian, false) { + elf::R_X86_64_64 => (RelocationKind::Absolute, 64), + elf::R_X86_64_PC32 => (RelocationKind::Relative, 32), + elf::R_X86_64_GOT32 => (RelocationKind::Got, 32), + elf::R_X86_64_PLT32 => (RelocationKind::PltRelative, 32), + elf::R_X86_64_GOTPCREL => (RelocationKind::GotRelative, 32), + elf::R_X86_64_32 => (RelocationKind::Absolute, 32), + elf::R_X86_64_32S => { + encoding = RelocationEncoding::X86Signed; + (RelocationKind::Absolute, 32) + } + elf::R_X86_64_16 => (RelocationKind::Absolute, 16), + elf::R_X86_64_PC16 => (RelocationKind::Relative, 16), + elf::R_X86_64_8 => (RelocationKind::Absolute, 8), + elf::R_X86_64_PC8 => (RelocationKind::Relative, 8), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_HEXAGON => match reloc.r_type(endian, false) { + elf::R_HEX_32 => (RelocationKind::Absolute, 32), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_LOONGARCH => match reloc.r_type(endian, false) { + elf::R_LARCH_32 => (RelocationKind::Absolute, 32), + elf::R_LARCH_64 => (RelocationKind::Absolute, 64), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_MIPS => match reloc.r_type(endian, is_mips64el) { + elf::R_MIPS_16 => (RelocationKind::Absolute, 16), + elf::R_MIPS_32 => (RelocationKind::Absolute, 32), + elf::R_MIPS_64 => (RelocationKind::Absolute, 64), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_MSP430 => match reloc.r_type(endian, false) { + elf::R_MSP430_32 => (RelocationKind::Absolute, 32), + elf::R_MSP430_16_BYTE => (RelocationKind::Absolute, 16), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_PPC => match reloc.r_type(endian, false) { + elf::R_PPC_ADDR32 => (RelocationKind::Absolute, 32), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_PPC64 => match reloc.r_type(endian, false) { + elf::R_PPC64_ADDR32 => (RelocationKind::Absolute, 32), + elf::R_PPC64_ADDR64 => (RelocationKind::Absolute, 64), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_RISCV => match reloc.r_type(endian, false) { + elf::R_RISCV_32 => (RelocationKind::Absolute, 32), + elf::R_RISCV_64 => (RelocationKind::Absolute, 64), + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_S390 => match reloc.r_type(endian, false) { + elf::R_390_8 => (RelocationKind::Absolute, 8), + elf::R_390_16 => (RelocationKind::Absolute, 16), + elf::R_390_32 => (RelocationKind::Absolute, 32), + elf::R_390_64 => (RelocationKind::Absolute, 64), + elf::R_390_PC16 => (RelocationKind::Relative, 16), + elf::R_390_PC32 => (RelocationKind::Relative, 32), + elf::R_390_PC64 => (RelocationKind::Relative, 64), + elf::R_390_PC16DBL => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::Relative, 16) + } + elf::R_390_PC32DBL => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::Relative, 32) + } + elf::R_390_PLT16DBL => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::PltRelative, 16) + } + elf::R_390_PLT32DBL => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::PltRelative, 32) + } + elf::R_390_GOT16 => (RelocationKind::Got, 16), + elf::R_390_GOT32 => (RelocationKind::Got, 32), + elf::R_390_GOT64 => (RelocationKind::Got, 64), + elf::R_390_GOTENT => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::GotRelative, 32) + } + elf::R_390_GOTOFF16 => (RelocationKind::GotBaseOffset, 16), + elf::R_390_GOTOFF32 => (RelocationKind::GotBaseOffset, 32), + elf::R_390_GOTOFF64 => (RelocationKind::GotBaseOffset, 64), + elf::R_390_GOTPC => (RelocationKind::GotBaseRelative, 64), + elf::R_390_GOTPCDBL => { + encoding = RelocationEncoding::S390xDbl; + (RelocationKind::GotBaseRelative, 32) + } + r_type => (RelocationKind::Elf(r_type), 0), + }, + elf::EM_SPARC | elf::EM_SPARC32PLUS | elf::EM_SPARCV9 => { + match reloc.r_type(endian, false) { + elf::R_SPARC_32 | elf::R_SPARC_UA32 => (RelocationKind::Absolute, 32), + elf::R_SPARC_64 | elf::R_SPARC_UA64 => (RelocationKind::Absolute, 64), + r_type => (RelocationKind::Elf(r_type), 0), + } + } + _ => (RelocationKind::Elf(reloc.r_type(endian, false)), 0), + }; + let sym = reloc.r_sym(endian, is_mips64el) as usize; + let target = if sym == 0 { + RelocationTarget::Absolute + } else { + RelocationTarget::Symbol(SymbolIndex(sym)) + }; + Relocation { + kind, + encoding, + size, + target, + addend: reloc.r_addend(endian).into(), + implicit_addend, + } +} + +/// A trait for generic access to `Rel32` and `Rel64`. +#[allow(missing_docs)] +pub trait Rel: Debug + Pod + Clone { + type Word: Into<u64>; + type Sword: Into<i64>; + type Endian: endian::Endian; + + fn r_offset(&self, endian: Self::Endian) -> Self::Word; + fn r_info(&self, endian: Self::Endian) -> Self::Word; + fn r_sym(&self, endian: Self::Endian) -> u32; + fn r_type(&self, endian: Self::Endian) -> u32; +} + +impl<Endian: endian::Endian> Rel for elf::Rel32<Endian> { + type Word = u32; + type Sword = i32; + type Endian = Endian; + + #[inline] + fn r_offset(&self, endian: Self::Endian) -> Self::Word { + self.r_offset.get(endian) + } + + #[inline] + fn r_info(&self, endian: Self::Endian) -> Self::Word { + self.r_info.get(endian) + } + + #[inline] + fn r_sym(&self, endian: Self::Endian) -> u32 { + self.r_sym(endian) + } + + #[inline] + fn r_type(&self, endian: Self::Endian) -> u32 { + self.r_type(endian) + } +} + +impl<Endian: endian::Endian> Rel for elf::Rel64<Endian> { + type Word = u64; + type Sword = i64; + type Endian = Endian; + + #[inline] + fn r_offset(&self, endian: Self::Endian) -> Self::Word { + self.r_offset.get(endian) + } + + #[inline] + fn r_info(&self, endian: Self::Endian) -> Self::Word { + self.r_info.get(endian) + } + + #[inline] + fn r_sym(&self, endian: Self::Endian) -> u32 { + self.r_sym(endian) + } + + #[inline] + fn r_type(&self, endian: Self::Endian) -> u32 { + self.r_type(endian) + } +} + +/// A trait for generic access to `Rela32` and `Rela64`. +#[allow(missing_docs)] +pub trait Rela: Debug + Pod + Clone { + type Word: Into<u64>; + type Sword: Into<i64>; + type Endian: endian::Endian; + + fn r_offset(&self, endian: Self::Endian) -> Self::Word; + fn r_info(&self, endian: Self::Endian, is_mips64el: bool) -> Self::Word; + fn r_addend(&self, endian: Self::Endian) -> Self::Sword; + fn r_sym(&self, endian: Self::Endian, is_mips64el: bool) -> u32; + fn r_type(&self, endian: Self::Endian, is_mips64el: bool) -> u32; +} + +impl<Endian: endian::Endian> Rela for elf::Rela32<Endian> { + type Word = u32; + type Sword = i32; + type Endian = Endian; + + #[inline] + fn r_offset(&self, endian: Self::Endian) -> Self::Word { + self.r_offset.get(endian) + } + + #[inline] + fn r_info(&self, endian: Self::Endian, _is_mips64el: bool) -> Self::Word { + self.r_info.get(endian) + } + + #[inline] + fn r_addend(&self, endian: Self::Endian) -> Self::Sword { + self.r_addend.get(endian) + } + + #[inline] + fn r_sym(&self, endian: Self::Endian, _is_mips64el: bool) -> u32 { + self.r_sym(endian) + } + + #[inline] + fn r_type(&self, endian: Self::Endian, _is_mips64el: bool) -> u32 { + self.r_type(endian) + } +} + +impl<Endian: endian::Endian> Rela for elf::Rela64<Endian> { + type Word = u64; + type Sword = i64; + type Endian = Endian; + + #[inline] + fn r_offset(&self, endian: Self::Endian) -> Self::Word { + self.r_offset.get(endian) + } + + #[inline] + fn r_info(&self, endian: Self::Endian, is_mips64el: bool) -> Self::Word { + self.get_r_info(endian, is_mips64el) + } + + #[inline] + fn r_addend(&self, endian: Self::Endian) -> Self::Sword { + self.r_addend.get(endian) + } + + #[inline] + fn r_sym(&self, endian: Self::Endian, is_mips64el: bool) -> u32 { + self.r_sym(endian, is_mips64el) + } + + #[inline] + fn r_type(&self, endian: Self::Endian, is_mips64el: bool) -> u32 { + self.r_type(endian, is_mips64el) + } +} |