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| author | Alan Modra <amodra@gmail.com> | 2023-07-13 13:32:42 +0930 |
|---|---|---|
| committer | Alan Modra <amodra@gmail.com> | 2023-07-13 14:27:51 +0930 |
| commit | 22e90ac5af46c01ee4972cf04e835266862bbb35 (patch) | |
| tree | c0dd8ba47fcfbb9c070540a8cc729a8b1fe0117f /bfd/elfcode.h | |
| parent | e726bad8af9a12dc7cbc5f148523fdf0a0b3cf5a (diff) | |
| download | gdb-22e90ac5af46c01ee4972cf04e835266862bbb35.zip gdb-22e90ac5af46c01ee4972cf04e835266862bbb35.tar.gz gdb-22e90ac5af46c01ee4972cf04e835266862bbb35.tar.bz2 | |
elf_object_p load of dynamic symbols
This fixes an uninitialised memory access on a fuzzed file:
0 0xf22e9b in offset_from_vma /src/binutils-gdb/bfd/elf.c:1899:2
1 0xf1e90f in _bfd_elf_get_dynamic_symbols /src/binutils-gdb/bfd/elf.c:2099:13
2 0x10e6a54 in bfd_elf32_object_p /src/binutils-gdb/bfd/elfcode.h:851:9
Hopefully it will also stop any attempt to load dynamic symbols from
eu-strip debug files.
* elfcode.h (elf_object_p): Do not attempt to load dynamic
symbols for a file with no section headers until all the
program headers are swapped in. Do not fail on eu-strip debug
files.
Diffstat (limited to 'bfd/elfcode.h')
| -rw-r--r-- | bfd/elfcode.h | 41 |
1 files changed, 26 insertions, 15 deletions
diff --git a/bfd/elfcode.h b/bfd/elfcode.h index aae66bc..b227792 100644 --- a/bfd/elfcode.h +++ b/bfd/elfcode.h @@ -819,6 +819,7 @@ elf_object_p (bfd *abfd) goto got_no_match; if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) goto got_no_match; + bool eu_strip_broken_phdrs = false; i_phdr = elf_tdata (abfd)->phdr; for (i = 0; i < i_ehdrp->e_phnum; i++, i_phdr++) { @@ -839,21 +840,31 @@ elf_object_p (bfd *abfd) abfd->read_only = 1; } } - if (i_phdr->p_filesz != 0) - { - if ((i_phdr->p_offset + i_phdr->p_filesz) > filesize) - goto got_no_match; - /* Try to reconstruct dynamic symbol table from PT_DYNAMIC - segment if there is no section header. */ - if (i_phdr->p_type == PT_DYNAMIC - && i_ehdrp->e_shstrndx == 0 - && i_ehdrp->e_shoff == 0 - && !_bfd_elf_get_dynamic_symbols (abfd, i_phdr, - elf_tdata (abfd)->phdr, - i_ehdrp->e_phnum, - filesize)) - goto got_no_match; - } + /* Detect eu-strip -f debug files, which have program + headers that describe the original file. */ + if (i_phdr->p_filesz != 0 + && (i_phdr->p_filesz > filesize + || i_phdr->p_offset > filesize - i_phdr->p_filesz)) + eu_strip_broken_phdrs = true; + } + if (!eu_strip_broken_phdrs + && i_ehdrp->e_shoff == 0 + && i_ehdrp->e_shstrndx == 0) + { + /* Try to reconstruct dynamic symbol table from PT_DYNAMIC + segment if there is no section header. */ + i_phdr = elf_tdata (abfd)->phdr; + for (i = 0; i < i_ehdrp->e_phnum; i++, i_phdr++) + if (i_phdr->p_type == PT_DYNAMIC) + { + if (i_phdr->p_filesz != 0 + && !_bfd_elf_get_dynamic_symbols (abfd, i_phdr, + elf_tdata (abfd)->phdr, + i_ehdrp->e_phnum, + filesize)) + goto got_no_match; + break; + } } } |