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, } 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 { 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 { 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 { 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, 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, 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>, } 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 { 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, R>; /// An iterator over the relocations for an `ElfSection64`. pub type ElfSectionRelocationIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> = ElfSectionRelocationIterator<'data, 'file, elf::FileHeader64, 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>, } 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 { 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( 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 => { if header.is_type_64() { 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), } } else { match reloc.r_type(endian, false) { elf::R_AARCH64_P32_ABS32 => (RelocationKind::Absolute, 32), 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_CSKY => match reloc.r_type(endian, false) { elf::R_CKCORE_ADDR32 => (RelocationKind::Absolute, 32), elf::R_CKCORE_PCREL32 => (RelocationKind::Relative, 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), elf::R_LARCH_32_PCREL => (RelocationKind::Relative, 32), elf::R_LARCH_B16 => { encoding = RelocationEncoding::LoongArchBranch; (RelocationKind::Relative, 16) } elf::R_LARCH_B21 => { encoding = RelocationEncoding::LoongArchBranch; (RelocationKind::Relative, 21) } elf::R_LARCH_B26 => { encoding = RelocationEncoding::LoongArchBranch; (RelocationKind::Relative, 26) } 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_SBF => match reloc.r_type(endian, false) { elf::R_SBF_64_64 => (RelocationKind::Absolute, 64), elf::R_SBF_64_32 => (RelocationKind::Absolute, 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), } } elf::EM_XTENSA => match reloc.r_type(endian, false) { elf::R_XTENSA_32 => (RelocationKind::Absolute, 32), elf::R_XTENSA_32_PCREL => (RelocationKind::Relative, 32), 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; type Sword: Into; 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 Rel for elf::Rel32 { 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 Rel for elf::Rel64 { 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; type Sword: Into; 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 Rela for elf::Rela32 { 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 Rela for elf::Rela64 { 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) } }