The ELF specification says that all ELF data structures are aligned to
their natural alignments both in memory and file. That means when we
access mmap'ed ELF files, we could assume that all data structures are
aligned properly.
However, in reality, we assume that the data structures are aligned only
to two bytes because .a files only guarantee that their member files are
aligned to two bytes in archive files. So the data access is already
unaligned.
This patch relaxes the alignment requirement even more, so that we
accept unaligned access to all ELF data structures.
This patch in particular makes lld bug-compatible with icc. Intel C
compiler doesn't seem to care about data alignment and generates unaligned
relocation sections (https://bugs.llvm.org/show_bug.cgi?id=35854).
I also saw another instance of compatibility issues with our internal tool
which creates unaligned section headers.
Because GNU linkers are not picky about alignment, looks like it is
not uncommon that ELF-generating tools create unaligned files.
There is a performance penalty with this patch on host machines on which
unaligned access is expensive. x86 and AArch64 are fine. ARMv6 is a
problem, but I don't think using ARMv6 machines as hosts is common, so I
believe it's not a real problem.
Differential Revision: https://reviews.llvm.org/D41978
llvm-svn: 322407
The previous code was discarding the error message from
createBinary() by calling errorToErrorCode().
This meant that such error were always reported unhelpfully
as "Invalid data was encountered while parsing the file".
Other tools such as llvm-objdump already produce a more
the error message in this case.
Differential Revision: https://reviews.llvm.org/D32985
llvm-svn: 302664
This has two advantages:
1) We slowly move away from ErrorOr to the new handling interface,
in the hope of having an uniform error handling in LLVM, eventually.
2) We're starting to have *meaningful* error messages for invalid
object ELF files, rather than a generic "parse error". At some point
we should include also the offset to improve the quality of the
diagnostic.
llvm-svn: 287081
with fix: edited invalid-section-index2.elf input to pass the new check and
fail on the same place it was intended to fail.
Original commit message:
Elf.h already has code checking that section table does not go past end of file.
Problem is that this check may not work on values greater than UINT64_MAX / Header->e_shentsize
because of calculation overflow.
Parch fixes the issue.
Differential revision: https://reviews.llvm.org/D25432
llvm-svn: 285586
Elf.h already has code checking that section table does not go past end of file.
Problem is that this check may not work on values greater than UINT64_MAX / Header->e_shentsize
because of calculation overflow.
Parch fixes the issue.
Differential revision: https://reviews.llvm.org/D25432
llvm-svn: 285285
Revealed using "id_000038,sig_11,src_000015,op_havoc,rep_16" from PR30540,
when sh_size was 0, crash happened.
Differential revision: https://reviews.llvm.org/D25091
llvm-svn: 285282
Patch checks that section pointer is aligned properly.
This should be done before getStringTable() call.
Differential revision: https://reviews.llvm.org/D25462
llvm-svn: 284387
With fix: hex edited the precompiled inputs from another testcases to pass new checks.
Original commit message:
[Object/ELF] - Check that e_shnum is null when e_shoff is.
Spec says (http://www.sco.com/developers/gabi/1998-04-29/ch4.eheader.html) :
e_shnum
This member holds the number of entries in the section header table. Thus the product of e_shentsize and e_shnum gives the section header table's size in bytes. If a file has no section header table, e_shnum holds the value zero.
Revealed using "id_000037,sig_11,src_000015,op_havoc,rep_8" from PR30540
That was the reason of crash in lld on incorrect input file.
Binary reduced using afl-min.
Differential revision: https://reviews.llvm.org/D25090
llvm-svn: 284374
Spec says (http://www.sco.com/developers/gabi/1998-04-29/ch4.eheader.html) :
e_shnum
This member holds the number of entries in the section header table. Thus the product of e_shentsize and e_shnum gives the section header table's size in bytes. If a file has no section header table, e_shnum holds the value zero.
Revealed using "id_000037,sig_11,src_000015,op_havoc,rep_8" from PR30540
That was the reason of crash in lld on incorrect input file.
Binary reduced using afl-min.
Differential revision: https://reviews.llvm.org/D25090
llvm-svn: 284371
If object has wrong (large) string table index and
also incorrect large value for amount of sections in total,
then section index passes the check:
if (Index >= getNumSections())
return object_error::invalid_section_index;
But result pointer then is far after end of file data, what
result in a crash.
Differential revision: https://reviews.llvm.org/D25081
llvm-svn: 284369
Bot does not like it: http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/17075
/mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/test/Object/invalid.test:70:32: error: expected string not found in input
INVALID-SEC-ADDRESS-ALIGNMENT: Invalid address alignment of section headers
^
<stdin>:1:1: note: scanning from here
/mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/Object/ELF.h:412:7: runtime error: upcast of misaligned address 0x000002d8b899 for type 'llvm::object::Elf_Shdr_Impl<llvm::object::ELFType<llvm::support::endianness::little, true> >', which requires 2 byte alignment
^
<stdin>:1:125: note: possible intended match here
/mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/Object/ELF.h:412:7: runtime error: upcast of misaligned address 0x000002d8b899 for type 'llvm::object::Elf_Shdr_Impl<llvm::object::ELFType<llvm::support::endianness::little, true> >', which requires 2 byte alignment
llvm-svn: 283858
sections_begin() may return unalignment pointer when Header->e_shoff isinvalid.
That may result in a crash in clients, for example we have one in LLD:
assert((PtrWord & ~PointerBitMask) == 0 &&
"Pointer is not sufficiently aligned");
fails when trying to push_back Elf_Shdr* (unaligned) into TinyPtrVector.
Patch forces check for alignment of Header->e_shoff.
Differential revision: https://reviews.llvm.org/D25368
llvm-svn: 283740
Previously code would access invalid memory and may crash,
patch fixes the issue.
Differential revision: https://reviews.llvm.org/D25187
llvm-svn: 283204
When using broken input object found using AFL,
getExtendedSymbolTableIndex() crashed because ShndxTable
was empty as object does not contain SHT_SYMTAB_SHNDX section.
Differential revision: https://reviews.llvm.org/D25189
llvm-svn: 283196
We used to keep both a section and a pointer to the first symbol.
The oddity of keeping a section for dynamic symbols is because there is
a DT_SYMTAB but no DT_SYMTABZ, so to print the table we have to find the
size via a section table.
The reason for still keeping a pointer to the first symbol is because we
want to be able to print relocation tables even if the section table is
missing (it is mandatory only for files used in linking).
With this patch we keep just a DynRegionInfo. This then requires
changing a few places that were asking for a Elf_Shdr but actually just
needed the first symbol.
The test change is to delete the program header pointer.
Now that we use the information of both DT_SYMTAB and .dynsym, we don't
depend on the sh_entsize of .dynsym if we see DT_SYMTAB.
Note: It is questionable if it is worth it putting the effort to report
broken sh_entsize given that in files with no section table we have to
assume it is sizeof(Elf_Sym), but that is for another change.
Extracted from r260488.
llvm-svn: 261099
Original messages:
Revert "[readobj] Handle ELF files with no section table or with no program headers."
Revert "[readobj] Dump DT_JMPREL relocations when outputting dynamic relocations."
r260489 depends on r260488 and among other issues r260488 deleted error
handling code.
llvm-svn: 260962
This adds support for finding the dynamic table and dynamic symbol table via
the section table or the program header table. If there's no section table an
attempt is made to figure out the length of the dynamic symbol table.
llvm-svn: 260488
This also improves the logic of what is an error:
* getSection(uint_32): only return an error if the index is out of bounds. The
index 0 corresponds to a perfectly valid entry.
* getSection(Elf_Sym): Returns null for symbols that normally don't have
sections and error for out of bound indexes.
In many places this just moves the report_fatal_error up the stack, but those
can then be fixed in smaller patches.
llvm-svn: 241156
This moves the error checking for string tables to getStringTable which returns
an ErrorOr<StringRef>.
This improves error checking, makes it uniform across all string tables and
makes it possible to check them once instead of once per name.
llvm-svn: 240950
This patch changes getRelocationAddend to use ErrorOr and considers it an error
to try to get the addend of a REL section.
If, for example, a x86_64 file has a REL section, that file is corrupted and
we should reject it.
Using ErrorOr is not ideal since we check the section type once per relocation
instead of once per section.
Checking once per section would involve getRelocationAddend just asserting and
callers checking the section before iterating over the relocations.
In any case, this is an improvement and includes a test.
llvm-svn: 240176
