diff options
Diffstat (limited to 'include/llvm/Object/ELF.h')
| -rw-r--r-- | include/llvm/Object/ELF.h | 158 |
1 files changed, 108 insertions, 50 deletions
diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h index bcdc190cc7dc..cf8e4529bad9 100644 --- a/include/llvm/Object/ELF.h +++ b/include/llvm/Object/ELF.h @@ -1,9 +1,8 @@ //===- ELF.h - ELF object file implementation -------------------*- C++ -*-===// // -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // @@ -45,10 +44,26 @@ getElfArchType(StringRef Object) { (uint8_t)Object[ELF::EI_DATA]); } -static inline Error createError(StringRef Err) { +static inline Error createError(const Twine &Err) { return make_error<StringError>(Err, object_error::parse_failed); } +template <class ELFT> class ELFFile; + +template <class ELFT> +std::string getSecIndexForError(const ELFFile<ELFT> *Obj, + const typename ELFT::Shdr *Sec) { + auto TableOrErr = Obj->sections(); + if (TableOrErr) + return "[index " + std::to_string(Sec - &TableOrErr->front()) + "]"; + // To make this helper be more convenient for error reporting purposes we + // drop the error. But really it should never be triggered. Before this point, + // our code should have called 'sections()' and reported a proper error on + // failure. + llvm::consumeError(TableOrErr.takeError()); + return "[unknown index]"; +} + template <class ELFT> class ELFFile { public: @@ -80,9 +95,7 @@ public: using Elf_Relr_Range = typename ELFT::RelrRange; using Elf_Phdr_Range = typename ELFT::PhdrRange; - const uint8_t *base() const { - return reinterpret_cast<const uint8_t *>(Buf.data()); - } + const uint8_t *base() const { return Buf.bytes_begin(); } size_t getBufSize() const { return Buf.size(); } @@ -115,8 +128,8 @@ public: SmallVectorImpl<char> &Result) const; uint32_t getRelativeRelocationType() const; - const char *getDynamicTagAsString(unsigned Arch, uint64_t Type) const; - const char *getDynamicTagAsString(uint64_t Type) const; + std::string getDynamicTagAsString(unsigned Arch, uint64_t Type) const; + std::string getDynamicTagAsString(uint64_t Type) const; /// Get the symbol for a given relocation. Expected<const Elf_Sym *> getRelocationSymbol(const Elf_Rel *Rel, @@ -165,11 +178,16 @@ public: /// Iterate over program header table. Expected<Elf_Phdr_Range> program_headers() const { if (getHeader()->e_phnum && getHeader()->e_phentsize != sizeof(Elf_Phdr)) - return createError("invalid e_phentsize"); + return createError("invalid e_phentsize: " + + Twine(getHeader()->e_phentsize)); if (getHeader()->e_phoff + (getHeader()->e_phnum * getHeader()->e_phentsize) > getBufSize()) - return createError("program headers longer than binary"); + return createError("program headers are longer than binary of size " + + Twine(getBufSize()) + ": e_phoff = 0x" + + Twine::utohexstr(getHeader()->e_phoff) + + ", e_phnum = " + Twine(getHeader()->e_phnum) + + ", e_phentsize = " + Twine(getHeader()->e_phentsize)); auto *Begin = reinterpret_cast<const Elf_Phdr *>(base() + getHeader()->e_phoff); return makeArrayRef(Begin, Begin + getHeader()->e_phnum); @@ -183,12 +201,12 @@ public: /// \param Err [out] an error to support fallible iteration, which should /// be checked after iteration ends. Elf_Note_Iterator notes_begin(const Elf_Phdr &Phdr, Error &Err) const { - if (Phdr.p_type != ELF::PT_NOTE) { - Err = createError("attempt to iterate notes of non-note program header"); - return Elf_Note_Iterator(Err); - } + assert(Phdr.p_type == ELF::PT_NOTE && "Phdr is not of type PT_NOTE"); + ErrorAsOutParameter ErrAsOutParam(&Err); if (Phdr.p_offset + Phdr.p_filesz > getBufSize()) { - Err = createError("invalid program header offset/size"); + Err = createError("PT_NOTE header has invalid offset (0x" + + Twine::utohexstr(Phdr.p_offset) + ") or size (0x" + + Twine::utohexstr(Phdr.p_filesz) + ")"); return Elf_Note_Iterator(Err); } return Elf_Note_Iterator(base() + Phdr.p_offset, Phdr.p_filesz, Err); @@ -202,12 +220,13 @@ public: /// \param Err [out] an error to support fallible iteration, which should /// be checked after iteration ends. Elf_Note_Iterator notes_begin(const Elf_Shdr &Shdr, Error &Err) const { - if (Shdr.sh_type != ELF::SHT_NOTE) { - Err = createError("attempt to iterate notes of non-note section"); - return Elf_Note_Iterator(Err); - } + assert(Shdr.sh_type == ELF::SHT_NOTE && "Shdr is not of type SHT_NOTE"); + ErrorAsOutParameter ErrAsOutParam(&Err); if (Shdr.sh_offset + Shdr.sh_size > getBufSize()) { - Err = createError("invalid section offset/size"); + Err = createError("SHT_NOTE section " + getSecIndexForError(this, &Shdr) + + " has invalid offset (0x" + + Twine::utohexstr(Shdr.sh_offset) + ") or size (0x" + + Twine::utohexstr(Shdr.sh_size) + ")"); return Elf_Note_Iterator(Err); } return Elf_Note_Iterator(base() + Shdr.sh_offset, Shdr.sh_size, Err); @@ -274,7 +293,7 @@ template <class ELFT> inline Expected<const typename ELFT::Shdr *> getSection(typename ELFT::ShdrRange Sections, uint32_t Index) { if (Index >= Sections.size()) - return createError("invalid section index"); + return createError("invalid section index: " + Twine(Index)); return &Sections[Index]; } @@ -286,7 +305,10 @@ getExtendedSymbolTableIndex(const typename ELFT::Sym *Sym, assert(Sym->st_shndx == ELF::SHN_XINDEX); unsigned Index = Sym - FirstSym; if (Index >= ShndxTable.size()) - return createError("index past the end of the symbol table"); + return createError( + "extended symbol index (" + Twine(Index) + + ") is past the end of the SHT_SYMTAB_SHNDX section of size " + + Twine(ShndxTable.size())); // The size of the table was checked in getSHNDXTable. return ShndxTable[Index]; @@ -333,20 +355,18 @@ ELFFile<ELFT>::getSection(const Elf_Sym *Sym, Elf_Sym_Range Symbols, } template <class ELFT> -inline Expected<const typename ELFT::Sym *> -getSymbol(typename ELFT::SymRange Symbols, uint32_t Index) { - if (Index >= Symbols.size()) - return createError("invalid symbol index"); - return &Symbols[Index]; -} - -template <class ELFT> Expected<const typename ELFT::Sym *> ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const { - auto SymtabOrErr = symbols(Sec); - if (!SymtabOrErr) - return SymtabOrErr.takeError(); - return object::getSymbol<ELFT>(*SymtabOrErr, Index); + auto SymsOrErr = symbols(Sec); + if (!SymsOrErr) + return SymsOrErr.takeError(); + + Elf_Sym_Range Symbols = *SymsOrErr; + if (Index >= Symbols.size()) + return createError("unable to get symbol from section " + + getSecIndexForError(this, Sec) + + ": invalid symbol index (" + Twine(Index) + ")"); + return &Symbols[Index]; } template <class ELFT> @@ -354,18 +374,26 @@ template <typename T> Expected<ArrayRef<T>> ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const { if (Sec->sh_entsize != sizeof(T) && sizeof(T) != 1) - return createError("invalid sh_entsize"); + return createError("section " + getSecIndexForError(this, Sec) + + " has an invalid sh_entsize: " + Twine(Sec->sh_entsize)); uintX_t Offset = Sec->sh_offset; uintX_t Size = Sec->sh_size; if (Size % sizeof(T)) - return createError("size is not a multiple of sh_entsize"); + return createError("section " + getSecIndexForError(this, Sec) + + " has an invalid sh_size (" + Twine(Size) + + ") which is not a multiple of its sh_entsize (" + + Twine(Sec->sh_entsize) + ")"); if ((std::numeric_limits<uintX_t>::max() - Offset < Size) || Offset + Size > Buf.size()) - return createError("invalid section offset"); + return createError("section " + getSecIndexForError(this, Sec) + + " has a sh_offset (0x" + Twine::utohexstr(Offset) + + ") + sh_size (0x" + Twine(Size) + + ") that cannot be represented"); if (Offset % alignof(T)) + // TODO: this error is untested. return createError("unaligned data"); const T *Start = reinterpret_cast<const T *>(base() + Offset); @@ -438,8 +466,10 @@ ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections) const { if (!Index) // no section string table. return ""; + // TODO: Test a case when the sh_link of the section with index 0 is broken. if (Index >= Sections.size()) - return createError("invalid section index"); + return createError("section header string table index " + Twine(Index) + + " does not exist"); return getStringTable(&Sections[Index]); } @@ -448,7 +478,9 @@ template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : Buf(Object) {} template <class ELFT> Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) { if (sizeof(Elf_Ehdr) > Object.size()) - return createError("Invalid buffer"); + return createError("invalid buffer: the size (" + Twine(Object.size()) + + ") is smaller than an ELF header (" + + Twine(sizeof(Elf_Ehdr)) + ")"); return ELFFile(Object); } @@ -459,16 +491,18 @@ Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const { return ArrayRef<Elf_Shdr>(); if (getHeader()->e_shentsize != sizeof(Elf_Shdr)) - return createError( - "invalid section header entry size (e_shentsize) in ELF header"); + return createError("invalid e_shentsize in ELF header: " + + Twine(getHeader()->e_shentsize)); const uint64_t FileSize = Buf.size(); - if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize) - return createError("section header table goes past the end of the file"); + return createError( + "section header table goes past the end of the file: e_shoff = 0x" + + Twine::utohexstr(SectionTableOffset)); // Invalid address alignment of section headers if (SectionTableOffset & (alignof(Elf_Shdr) - 1)) + // TODO: this error is untested. return createError("invalid alignment of section headers"); const Elf_Shdr *First = @@ -479,6 +513,7 @@ Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const { NumSections = First->sh_size; if (NumSections > UINT64_MAX / sizeof(Elf_Shdr)) + // TODO: this error is untested. return createError("section table goes past the end of file"); const uint64_t SectionTableSize = NumSections * sizeof(Elf_Shdr); @@ -505,10 +540,14 @@ template <typename T> Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr *Section, uint32_t Entry) const { if (sizeof(T) != Section->sh_entsize) + // TODO: this error is untested. return createError("invalid sh_entsize"); size_t Pos = Section->sh_offset + Entry * sizeof(T); if (Pos + sizeof(T) > Buf.size()) - return createError("invalid section offset"); + return createError("unable to access section " + + getSecIndexForError(this, Section) + " data at 0x" + + Twine::utohexstr(Pos) + + ": offset goes past the end of file"); return reinterpret_cast<const T *>(base() + Pos); } @@ -534,6 +573,7 @@ ELFFile<ELFT>::getSection(const StringRef SectionName) const { if (*SecNameOrErr == SectionName) return &Sec; } + // TODO: this error is untested. return createError("invalid section name"); } @@ -541,15 +581,24 @@ template <class ELFT> Expected<StringRef> ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const { if (Section->sh_type != ELF::SHT_STRTAB) - return createError("invalid sh_type for string table, expected SHT_STRTAB"); + return createError("invalid sh_type for string table section " + + getSecIndexForError(this, Section) + + ": expected SHT_STRTAB, but got " + + object::getELFSectionTypeName(getHeader()->e_machine, + Section->sh_type)); auto V = getSectionContentsAsArray<char>(Section); if (!V) return V.takeError(); ArrayRef<char> Data = *V; if (Data.empty()) + // TODO: this error is untested. return createError("empty string table"); if (Data.back() != '\0') - return createError("string table non-null terminated"); + return createError(object::getELFSectionTypeName(getHeader()->e_machine, + Section->sh_type) + + " string table section " + + getSecIndexForError(this, Section) + + " is non-null terminated"); return StringRef(Data.begin(), Data.size()); } @@ -577,9 +626,13 @@ ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section, const Elf_Shdr &SymTable = **SymTableOrErr; if (SymTable.sh_type != ELF::SHT_SYMTAB && SymTable.sh_type != ELF::SHT_DYNSYM) + // TODO: this error is untested. return createError("invalid sh_type"); if (V.size() != (SymTable.sh_size / sizeof(Elf_Sym))) - return createError("invalid section contents size"); + return createError("SHT_SYMTAB_SHNDX section has sh_size (" + + Twine(SymTable.sh_size) + + ") which is not equal to the number of symbols (" + + Twine(V.size()) + ")"); return V; } @@ -598,6 +651,7 @@ ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec, Elf_Shdr_Range Sections) const { if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM) + // TODO: this error is untested. return createError( "invalid sh_type for symbol table, expected SHT_SYMTAB or SHT_DYNSYM"); auto SectionOrErr = object::getSection<ELFT>(Sections, Sec.sh_link); @@ -625,7 +679,11 @@ Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section, if (Offset == 0) return StringRef(); if (Offset >= DotShstrtab.size()) - return createError("invalid string offset"); + return createError("a section " + getSecIndexForError(this, Section) + + " has an invalid sh_name (0x" + + Twine::utohexstr(Offset) + + ") offset which goes past the end of the " + "section name string table"); return StringRef(DotShstrtab.data() + Offset); } |