doc/bfdint.texi and comments in the aout and som code about this
function are just wrong, and its name is not very apt. Better would
be _bfd_mostly_destroy, and we certainly should not be saying anything
about the possibility of later recreating anything lost by this
function. What's more, if _bfd_free_cached_info is called when
creating an archive map to reduce memory usage by throwing away
symbols, the target _close_and_cleanup function won't have access to
tdata or section bfd_user_data to tidy memory. This means most of the
target _close_and_cleanup function won't do anything, and therefore
sometimes will result in memory leaks.
This patch fixes the documentation problems and moves most of the
target _close_and_cleanup code to target _bfd_free_cached_info.
Another notable change is that bfd_generic_bfd_free_cached_info is now
defined as _bfd_free_cached_info rather than _bfd_bool_bfd_true,
ie. the default now frees objalloc memory.
When rewriting the program headers, don't warn an empty PT_LOAD with the
program headers.
bfd/
PR binutils/30508
* elf.c (rewrite_elf_program_header): Don't warn if an empty
PT_LOAD contains the program headers.
ld/
PR binutils/30508
* testsuite/ld-elf/pr30508.d: New file.
* testsuite/ld-elf/pr30508.s: Likewise.
bfd_elf_bfd_from_remote_memory is just a wrapper, and the function
could be implemented for other formats. Move it to opncls.c because
it acts a little like some of the other bfd_open* routines. Also give
it the usual FUNCTION etc. comment so prototypes and docs are handled
automatically.
* elf.c (bfd_elf_bfd_from_remote_memory): Move to..
* opncls.c: ..here, add FUNCTION comment.
* bfd-in.h (bfd_elf_bfd_from_remote_memory): Delete prototype.
* bfd-in2.h: Regenerate.
This is a fuzzing PR, with a testcase involving a SHF_ALLOC and
SHF_COMPRESSED SHT_RELA section, ie. a compressed dynamic reloc
section. BFD doesn't handle compressed relocation sections, with most
of the code reading relocs using sh_size (often no bfd section is
created) but in the case of SHF_ALLOC dynamic relocs we had some code
using the bfd section size. This led to a mismatch, sh_size is
compressed, size is uncompressed, and from that some uninitialised
memory. Consistently using sh_size is enough to fix this PR, but I've
also added tests to exclude SHF_COMPRESSED reloc sections from
consideration.
PR 30362
* elf.c (bfd_section_from_shdr): Exclude reloc sections with
SHF_COMPRESSED flag from normal reloc processing.
(_bfd_elf_get_dynamic_reloc_upper_bound): Similarly exclude
SHF_COMPRESSED sections from consideration. Use sh_size when
sizing to match slurp_relocs.
(_bfd_elf_canonicalize_dynamic_reloc): Likewise.
(_bfd_elf_get_synthetic_symtab): Use NUM_SHDR_ENTRIES to size
plt relocs.
* elf32-arm.c (elf32_arm_get_synthetic_symtab): Likewise.
* elf32-ppc.c (ppc_elf_get_synthetic_symtab): Likewise.
* elf64-ppc.c (ppc64_elf_get_synthetic_symtab): Likewise.
* elfxx-mips.c (_bfd_mips_elf_get_synthetic_symtab): Likewise.
The bfd_elf_hash loop is taken straight from the sysV document, but it
is poorly optimized. This refactoring removes about 5 x86 insns from
the 15 insn loop.
1) The if (..) is meaningless -- we're xoring with that value, and of
course xor 0 is a nop. On x86 (at least) we actually compute the xor'd
value and then cmov. Removing the if test removes the cmov.
2) The 'h ^ g' to clear the top 4 bits is not needed, as those 4 bits
will be shifted out in the next iteration. All we need to do is sink
a mask of those 4 bits out of the loop.
3) anding with 0xf0 after shifting by 24 bits can allow betterin
encoding on RISC ISAs than masking with '0xf0 << 24' before shifting.
RISC ISAs often require materializing larger constants.
bfd/
* elf.c (bfd_elf_hash): Refactor to optimize loop.
(bfd_elf_gnu_hash): Refactor to use 32-bit type.
It's wrong to have an alloc reloc section trying to use a non-alloc
symbol table.
* elf.c (assign_section_numbers <SHT_REL, SHT_RELA>): Correct
comment. Always set sh_link to .dynsym for alloc reloc
sections and to .symtab for non-alloc.
Layout in rewrite_elf_program_header is really done by lma, even if
program headers are going to have their p_paddr forced to zero. Thus
when not matching against an existing segment, don't try to use a
"vma" from elf_segment_map.
* elf.c (is_contained_by): Replace "bed" param with "use_vaddr".
(IS_SECTION_IN_INPUT_SEGMENT): Adjust is_contained_by call.
(rewrite_elf_program_header): Always match against lma in
calls to is_contained_by using new maps.
QNX provides some .note subsections. QNT_STACK is the one controling
the stack allocation.
bfd/ChangeLog:
* elf.c (BFD_QNT_CORE_INFO): Delete.
(BFD_QNT_CORE_STATUS): Likewise.
(BFD_QNT_CORE_GREG): Likewise.
(BFD_QNT_CORE_FPREG): Likewise.
(elfcore_grok_nto_note): Replace BFD_QNT_* by QNT_*.
binutils/ChangeLog:
* readelf.c (get_qnx_elfcore_note_type): New function.
(print_qnx_note): New function.
(process_note): Add support for QNX support.
include/ChangeLog:
* elf/common.h (QNT_DEBUG_FULLPATH): New define.
(QNT_DEBUG_RELOC): New define.
(QNT_STACK): New define.
(QNT_GENERATOR): New define.
(QNT_DEFAULT_LIB): New define.
(QNT_CORE_SYSINFO): New define.
(QNT_CORE_INFO): New define.
(QNT_CORE_STATUS): New define.
(QNT_CORE_GREG): New define.
(QNT_CORE_FPREG): New define.
(QNT_LINK_MAP): New define.
Writing out zeros is counterproductive if a file system supports
sparse files. A very large gap need not take much actual disk space,
but it usually will if zeros are written.
memory_bseek also supports not writing out zeros in a gap.
* elf.c (write_zeros): Delete.
(assign_file_positions_for_load_sections): Don't call write_zeros.
Comment.
The newer update-copyright.py fixes file encoding too, removing cr/lf
on binutils/bfdtest2.c and ld/testsuite/ld-cygwin/exe-export.exp, and
embedded cr in binutils/testsuite/binutils-all/ar.exp string match.
That's this line in elf_parse_notes:
while (p < buf + size)
* elf.c (_bfd_elf_make_section_from_shdr): Don't call
elf_parse_notes when sh_size is zero.
Tidies:
- Move stuff from bfd-in.h and libbfd.c to compress.c
- Delete COMPRESS_DEBUG from enum compressed_debug_section_type
- Move compress_debug field out of link_info to ld_config.
Fixes:
- Correct test in bfd_convert_section_setup to use obfd flags,
not ibfd.
- Apply bfd_applicable_file_flags to compression bfd flags added
by gas and ld to the output bfd.
bfd/
* bfd-in.h (enum compressed_debug_section_type),
(struct compressed_type_tuple),
(bfd_get_compression_algorithm),
(bfd_get_compression_algorithm_name),
* libbfd.c (compressed_debug_section_names),
(bfd_get_compression_algorithm),
(bfd_get_compression_algorithm_name): Move..
* compress.c: ..to here, deleting COMPRESS_DEBUG from
enum compressed_debug_section_type.
(bfd_convert_section_setup): Test obfd flags not ibfd for
compression flags.
* elf.c (elf_fake_sections): Replace link_info->compress_debug
test with abfd->flags test.
* bfd-in2.h: Regenerate.
binutils/
* objcopy.c (copy_file): Tidy setting of bfd compress flags.
Expand comment.
gas/
* write.c (compress_debug): Test bfd compress flags rather than
flag_compress_debug.
(write_object_file): Apply bfd_applicable_file_flags to compress
debug flags added to output bfd.
include/
* bfdlink.h (struct bfd_link_info): Delete compress_debug.
ld/
* ld.h (ld_config_type): Add compress_debug.
* emultempl/elf.em: Replace references to link_info.compress_debug
with config.compress_debug.
* lexsup.c (elf_static_list_options): Likewise.
* ldmain.c (main): Likewise. Apply bfd_applicable_file_flags
to compress debug flags added to output bfd.
This flag also isn't needed, except for some sanity checks which we
can omit.
* elf.c (elf_fake_sections): Don't set SEC_ELF_COMPRESS for
compressed debug sections, just leave sh_name as -1.
(assign_file_positions_for_non_load_sections),
(assign_file_positions_except_relocs): Decide whether a section
needs compressing and thus should not have its file offset set
by looking at sh_name.
(_bfd_elf_assign_file_positions_for_non_load): Similarly decide
which sections need compressing.
* elflink.c (bfd_elf_final_link): Don't test SEC_ELF_COMPRESS.
* merge.c (_bfd_write_merged_section): Likewise.
* section.c (SEC_ELF_COMPRESS): Don't define.
(SEC_ELF_PURECODE): Renumber.
* bfd-in2.h: Regenerate.
SEC_ELF_RENAME is a flag used to effect section name changes when
compressing/decompressing zlib-gnu debug sections. This can be
accomplished more directly in one of the objcopy specific bfd
functions. Renaming for ld input is simplified too. Ld input object
files always have BFD_DECOMPRESS set.
bfd/
* compress.c (bfd_convert_section_size): Rename to..
(bfd_convert_section_setup): ..this. Handle objcopy renaming
of compressed/decompressed debug sections.
* elf.c (_bfd_elf_make_section_from_shdr): Only rename zdebug
input for linker.
(elf_fake_sections): Don't handle renaming of debug sections for
objcopy here.
* section.c (SEC_ELF_RENAME): Delete.
* bfd-in2.h: Regenerate.
binutils/
* objcopy.c (setup_section): Call bfd_convert_section_setup.
Don't call bfd_convert_section_size.
Define an enum instead of using ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD
in bfd and binutils, and move some functions from bfd.c to compress.c.
When looking at the COFF/PE debug compression support, I wondered
about extending it to support zstd. I likely won't do that, but
the compression header ch_type field isn't just ELF specific if these
headers are to be used in COFF/PE too.
bfd/
* bfd.c (bfd_update_compression_header),
(bfd_check_compression_header, bfd_get_compression_header_size),
(bfd_convert_section_size, bfd_convert_section_contents): Move to..
* compress.c: ..here.
(enum compression_type): New. Use it throughout file.
* elf.c (_bfd_elf_make_section_from_shdr): Replace uses of
ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD with ch_compress_zlib and
ch_compress_zstd.
* bfd-in2.h: Regenerate.
binutils/
* readelf.c (process_section_headers, dump_section_as_strings),
(dump_section_as_bytes, load_specific_debug_section): Replace
uses of ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD with
ch_compress_zlib and ch_compress_zstd.
Move a couple of elf.c functions to compress.c.
* compress.c (bfd_debug_name_to_zdebug): New inline function.
(bfd_zdebug_name_to_debug): Likewise.
* elf.c (convert_debug_to_zdebug, convert_zdebug_to_debug): Delete.
(_bfd_elf_make_section_from_shdr, elf_fake_sections),
(_bfd_elf_assign_file_positions_for_non_load): Adjust to suit.
* coffgen.c (make_a_section_from_file): Use new inlines here.
The linker merges all the input .sframe sections. When merging, the
linker verifies that all the input .sframe sections have the same
abi/arch.
The linker uses libsframe library to perform key actions on the
.sframe sections - decode, read, and create output data. This
implies buildsystem changes to make and install libsframe before
libbfd.
The linker places the output .sframe section in a new segment of its
own: PT_GNU_SFRAME. A new segment is not added, however, if the
generated .sframe section is empty.
When a section is discarded from the final link, the corresponding
entries in the .sframe section for those functions are also deleted.
The linker sorts the SFrame FDEs on start address by default and sets
the SFRAME_F_FDE_SORTED flag in the .sframe section.
This patch also adds support for generation of SFrame unwind
information for the .plt* sections on x86_64. SFrame unwind info is
generated for IBT enabled PLT, lazy/non-lazy PLT.
The existing linker option --no-ld-generated-unwind-info has been
adapted to include the control of whether .sframe unwind information
will be generated for the linker generated sections like PLT.
Changes to the linker script have been made as necessary.
ChangeLog:
* Makefile.def: Add install dependency on libsframe for libbfd.
* Makefile.in: Regenerated.
* bfd/Makefile.am: Add elf-sframe.c
* bfd/Makefile.in: Regenerated.
* bfd/bfd-in2.h (SEC_INFO_TYPE_SFRAME): Regenerated.
* bfd/configure: Regenerate.
* bfd/configure.ac: Add elf-sframe.lo.
* bfd/elf-bfd.h (struct sframe_func_bfdinfo): New struct.
(struct sframe_dec_info): Likewise.
(struct sframe_enc_info): Likewise.
(struct elf_link_hash_table): New member for encoded .sframe
object.
(struct output_elf_obj_tdata): New member.
(elf_sframe): New access macro.
(_bfd_elf_set_section_sframe): New declaration.
* bfd/elf.c (get_segment_type): Handle new segment
PT_GNU_SFRAME.
(bfd_section_from_phdr): Likewise.
(get_program_header_size): Likewise.
(_bfd_elf_map_sections_to_segments): Likewise.
* bfd/elf64-x86-64.c (elf_x86_64_link_setup_gnu_properties): Add
contents to the .sframe sections or .plt* entries.
* bfd/elflink.c (elf_section_ignore_discarded_relocs): Handle
SEC_INFO_TYPE_SFRAME.
(_bfd_elf_default_action_discarded): Handle .sframe section.
(elf_link_input_bfd): Merge .sframe section.
(bfd_elf_final_link): Write the output .sframe section.
(bfd_elf_discard_info): Handle discarding .sframe section.
* bfd/elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Create
.sframe section for .plt and .plt.sec.
(_bfd_x86_elf_finish_dynamic_sections): Handle .sframe from
.plt* sections.
* bfd/elfxx-x86.h (PLT_SFRAME_FDE_START_OFFSET): New
definition.
(SFRAME_PLT0_MAX_NUM_FRES): Likewise.
(SFRAME_PLTN_MAX_NUM_FRES): Likewise.
(struct elf_x86_sframe_plt): New structure.
(struct elf_x86_link_hash_table): New member.
(struct elf_x86_init_table): New members for .sframe
creation.
* bfd/section.c: Add new definition SEC_INFO_TYPE_SFRAME.
* binutils/readelf.c (get_segment_type): Handle new segment
PT_GNU_SFRAME.
* ld/ld.texi: Update documentation for
--no-ld-generated-unwind-info.
* ld/scripttempl/elf.sc: Support .sframe sections.
* ld/Makefile.am (TESTSFRAMELIB): Use it.
(check-DEJAGNU): Likewise.
* ld/Makefile.in: Regenerated.
* ld/configure.ac (TESTSFRAMELIB): Set to the .so or .a like TESTBFDLIB.
* ld/configure: Regenerated.
* bfd/elf-sframe.c: New file.
include/ChangeLog:
* elf/common.h (PT_GNU_SFRAME): New definition.
* elf/internal.h (struct elf_segment_map): Handle new segment
type PT_GNU_SFRAME.
ld/testsuite/ChangeLog:
* ld/testsuite/ld-bootstrap/bootstrap.exp: Add SFRAMELIB.
* ld/testsuite/ld-aarch64/aarch64-elf.exp: Add new test
sframe-simple-1.
* ld/testsuite/ld-aarch64/sframe-bar.s: New file.
* ld/testsuite/ld-aarch64/sframe-foo.s: Likewise.
* ld/testsuite/ld-aarch64/sframe-simple-1.d: Likewise.
* ld/testsuite/ld-sframe/sframe-empty.d: New test.
* ld/testsuite/ld-sframe/sframe-empty.s: New file.
* ld/testsuite/ld-sframe/sframe.exp: New testsuite.
* ld/testsuite/ld-x86-64/sframe-bar.s: New file.
* ld/testsuite/ld-x86-64/sframe-foo.s: Likewise.
* ld/testsuite/ld-x86-64/sframe-simple-1.d: Likewise.
* ld/testsuite/ld-x86-64/sframe-plt-1.d: Likewise.
* ld/testsuite/ld-x86-64/sframe-simple-1.d: Likewise.
* ld/testsuite/ld-x86-64/x86-64.exp: Add new tests -
sframe-simple-1, sframe-plt-1.
* ld/testsuite/lib/ld-lib.exp: Add new proc to check if
assembler supports SFrame section.
* ld/testsuite/ld-sframe/discard.d: New file.
* ld/testsuite/ld-sframe/discard.ld: Likewise.
* ld/testsuite/ld-sframe/discard.s: Likewise.
The external reloc size check was wrong. Here asect is the code/data
section, not the reloc section. So using this_hdr gave the size of
the code/data section.
* elf.c (_bfd_elf_get_reloc_upper_bound): Properly get
external size from reloc headers.
Commit 2cac01e3ff lacked support for objcopy changing compression
style. Add that support, which meant a rewrite of
bfd_compress_section_contents. In the process I've fixed some memory
leaks.
* compress.c (bfd_is_section_compressed_info): Rename from
bfd_is_section_compressed_with_header and add ch_type param
to return compression header ch_type field.
Update all callers.
(decompress_section_contents): Remove buffer and size params.
Rewrite. Update callers.
(bfd_init_section_compress_status): Free contents on failure.
(bfd_compress_section): Likewise.
* elf.c (_bfd_elf_make_section_from_shdr): Support objcopy
changing between any of the three compression schemes. Report
"unable to compress/decompress" rather than "unable to
initialize compress/decompress status" on compress/decompress
failures.
* bfd-in2.h: Regenerate.
Enable zlib-gnu compression for .gnu.debuglto_.debug_*. This differs
from zlib-gnu for .debug_* where the name is changed to .zdebug_*.
The name change isn't really needed.
bfd/
* elf.c (elf_fake_sections): Replace "." with ".z" in debug
section names only when name was ".d*", ie. ".debug_*".
(_bfd_elf_assign_file_positions_for_non_load): Likewise.
gas/
* write.c (compress_debug): Compress .gnu.debuglto_.debug_*
for zlib-gnu too. Compress .gnu.linkonce.wi.*.
Right now, when using LTO, the intermediate object files do contain
debug info in sections starting with .gnu.debuglto_ prefix and are
not compressed when --compress-debug-sections is used.
It's a mistake and we can save quite some disk space. The following
example comes from tramp3d when the corresponding LTO sections
are compressed with zlib:
$ bloaty tramp3d-v4-v2.o -- tramp3d-v4.o
FILE SIZE VM SIZE
-------------- --------------
+83% +10 [ = ] 0 [Unmapped]
-68.0% -441 [ = ] 0 .gnu.debuglto_.debug_line
-52.3% -759 [ = ] 0 .gnu.debuglto_.debug_line_str
-62.4% -3.24Ki [ = ] 0 .gnu.debuglto_.debug_abbrev
-64.8% -1.12Mi [ = ] 0 .gnu.debuglto_.debug_info
-88.8% -4.58Mi [ = ] 0 .gnu.debuglto_.debug_str
-27.7% -5.70Mi [ = ] 0 TOTAL
bfd/ChangeLog:
* elf.c (_bfd_elf_make_section_from_shdr): Compress all debug
info sections.
gas/ChangeLog:
* write.c (compress_debug): Compress also ".gnu.debuglto_.debug_"
if the compression algorithm is different from zlib-gnu.
PR29397 PR29563: Add new configure option --with-zstd which defaults to
auto. If pkgconfig/libzstd.pc is found, define HAVE_ZSTD and support
zstd compressed debug sections for most tools.
* bfd: for addr2line, objdump --dwarf, gdb, etc
* gas: support --compress-debug-sections=zstd
* ld: support ELFCOMPRESS_ZSTD input and --compress-debug-sections=zstd
* objcopy: support ELFCOMPRESS_ZSTD input for
--decompress-debug-sections and --compress-debug-sections=zstd
* gdb: support ELFCOMPRESS_ZSTD input. The bfd change references zstd
symbols, so gdb has to link against -lzstd in this patch.
If zstd is not supported, ELFCOMPRESS_ZSTD input triggers an error. We
can avoid HAVE_ZSTD if binutils-gdb imports zstd/ like zlib/, but this
is too heavyweight, so don't do it for now.
```
% ld/ld-new a.o
ld/ld-new: a.o: section .debug_abbrev is compressed with zstd, but BFD is not built with zstd support
...
% ld/ld-new a.o --compress-debug-sections=zstd
ld/ld-new: --compress-debug-sections=zstd: ld is not built with zstd support
% binutils/objcopy --compress-debug-sections=zstd a.o b.o
binutils/objcopy: --compress-debug-sections=zstd: binutils is not built with zstd support
% binutils/objcopy b.o --decompress-debug-sections
binutils/objcopy: zstd.o: section .debug_abbrev is compressed with zstd, but BFD is not built with zstd support
...
```
bfd_malloc_and_get_section performs some sanity checks on the section
size before allocating memory. This patch avails the stab
nearest_line code of that sanity checking, and tidies up memory
afterward.
* coffgen.c (_bfd_coff_close_and_cleanup): Call _bfd_stab_cleanup.
* elf.c (_bfd_elf_close_and_cleanup): Likewise.
* syms.c (_bfd_stab_section_find_nearest_line): Set *pinfo earlier.
Use bfd_malloc_and_get_section. Free malloc'd buffers on failure.
Malloc indextable.
(_bfd_stab_cleanup): New function.
* libbfd-in.h (_bfd_stab_cleanup): Declare.
* libbfd.h: Regnerate.
It doesn't make sense to try to compress a section without contents
since those sections take no space on disk. Compression can only
increase the disk image size.
* coffgen.c (make_a_section_from_file): Exclude !SEC_HAS_CONTENTS
sections from compression and decompression.
* elf.c (_bfd_elf_make_section_from_shdr): Likewise.
Allow and ignore an empty section.
PR 29566
* elf.c (bfd_section_from_shdr): Don't set elf_dynverdef or
elf_dynverref for empty sections.
(_bfd_elf_slurp_version_tables): Remove now redundant tests.
PR 29532
bfd * elf.c (setup_group): Do not return false if there is no group
information available.
bionutils* objcopy.c (setup_section): Leave group sections intact when
creating separate debuginfo files.
bfd_find_nearest_line_with_alt functions like bfd_find_nearest_line with
the addition of a parameter for specifying the filename of a supplementary
debug file such as one referenced by .gnu_debugaltlink or .debug_sup.
This patch focuses on implementing bfd_find_nearest_line_with_alt
support for ELF/DWARF2 .gnu_debugaltlink. For other targets this
function simply sets the invalid_operation bfd_error.
I don't think it makes any sense for a SHT_RELR section to specify a
symbol table with sh_link. SHT_RELR relocations don't use symbols.
There is no real need to specify sh_info either, SHT_RELR is not for
relocatable object files. Anyway, fuzzers of course don't restrict
themselves to even half-sensible objects. So they found a hole in
objcopy using a non-alloc SHT_RELR in an ET_EXEC. In that case BFD
set up the SHT_RELR section as if it were a SHT_REL against the
sh_info target section. When it came to reading in the target section
relocs, the count was horribly wrong which caused a buffer overflow.
* elf.c (bfd_section_from_shdr <SHT_RELR>): Always just make a
normal section, don't treat it as a reloc section.
objcopy of broken SHT_GROUP sections shouldn't write garbage.
* elf.c (bfd_elf_set_group_contents): If number of entries is
unexpected, fill out section with zeros.
Swap params of is_note, so they are section, segment like others used
in rewrite_elf_program_header. Whitespace fixes, plus wrapping of
overlong lines.
This patch, in order of significance:
1) Replaces some macros with inline functions.
2) Those inline functions catch and avoid arithmetic overflows when
comparing addresses.
3) When assigning sections to segments (IS_SECTION_IN_INPUT_SEGMENT)
use bed->want_p_paddr_set_to_zero to decide whether lma vs p_paddr
or vma vs p_vaddr should be tested. When remapping, use the same
test, and use is_note rather than the more restrictive
IS_COREFILE_NOTE.
It's important that the later tests not be more restrictive. If they
are it can lead to the situation triggered by the testcases, where a
section seemingly didn't fit and thus needed a new mapping. It didn't
fit the new mapping either, and this repeated until memory exhausted.
PR 29495
* elf.c (SEGMENT_END, SECTION_SIZE, IS_CONTAINED_BY_VMA): Delete.
(IS_CONTAINED_BY_LMA, IS_NOTE, IS_COREFILE_NOTE): Delete.
(segment_size, segment_end, section_size): New inline function.
(is_contained_by, is_note): Likewise.
(rewrite_elf_program_header): Use new functions.
Fuzzed input files with sizes of .dynamic not a multiple of dynamic
tag size can result in reading past the end of the buffer with the
current simple checks. Fix that, and use the same check in other
files that process input object .dynamic section. (There is no need
for buffer overflow checks in the linker's generated .dynamic
section.)
* elf32-ppc.c (ppc_elf_get_synthetic_symtab): Sanity check
.dynamic content buffer reads.
* elf64-ppc.c (ppc64_elf_get_synthetic_symtab): Likewise.
* elf64-ia64-vms.c (elf64_vms_link_add_object_symbols): Likewise.
* elf.c (_bfd_elf_print_private_bfd_data): Simplify .dynamic
buffer sanity checks.
* elflink.c (elf_link_add_object_symbols): Avoid possible UB
subtracting sizeof_dyn from pointer.
BFD_VMA_FMT can't be used in format strings that need to be
translated, because the translation won't work when the type of
bfd_vma differs from the machine used to compile .pot files. We've
known about this for a long time, but patches slip through review.
So just get rid of BFD_VMA_FMT, instead using the appropriate PRId64,
PRIu64, PRIx64 or PRIo64 and SCN variants for scanf. The patch is
mostly mechanical, the only thing requiring any thought is casts
needed to preserve PRId64 output from bfd_vma values, or to preserve
one of the unsigned output formats from bfd_signed_vma values.
Reset alignment for each PT_LOAD segment to avoid using alignment from
the previous PT_LOAD segment.
bfd/
PR ld/29435
* elf.c (assign_file_positions_for_load_sections): Reset
alignment for each PT_LOAD segment.
ld/
PR ld/29435
* testsuite/ld-elf/pr29435.d: New file.
* testsuite/ld-elf/pr29435.s: Likewise.
Even when there are no symbols (e.g. all relocations being against
absolute values), a symbol table (with just the first placeholder entry)
needs to be emitted. Otherwise tools like objdump won't properly process
the relocations. The respective checks in assign_section_numbers() and
_bfd_elf_compute_section_file_positions() support also this view. Oddly
enough so far HAS_RELOC was only set when reading in an object file, but
not when generating one anew; the flag would only have been cleared when
no relocations were found (anymore).
While there also amend the affected function's leading comment to also
mention gas.
commit 74e315dbfe
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Mon Dec 13 19:46:04 2021 -0800
elf: Set p_align to the minimum page size if possible
may ignore p_align of PT_GNU_STACK when copying ELF program header if
the maximum page size is larger than p_align of PT_LOAD segments. Copy
p_align of PT_GNU_STACK since p_align of PT_GNU_STACK describes stack
alignment, not page size,
PR binutils/29319
* elf.c (copy_elf_program_header): Copy p_align of PT_GNU_STACK
for stack alignment.
Generate a .note.package FDO package metadata ELF note, following
the spec: https://systemd.io/ELF_PACKAGE_METADATA/
If the jansson library is available at build time (and it is explicitly
enabled), link ld to it, and use it to validate that the input is
correct JSON, to avoid writing garbage to the file. The
configure option --enable-jansson has to be used to explicitly enable
it (error out when not found). This allows bootstrappers (or others who
are not interested) to seamlessly skip it without issues.
If you load a core file into GDB with the --write option, or "set
write on" (equivalent), and then poke memory expecting it to patch the
core binary, you'll notice something odd -- the write seems to
succeed, but in reality, it doesn't. The value you wrote doesn't
persist. Like so:
$ gdb -q --write -c testsuite/outputs/gdb.base/patch/gcore.test
[New LWP 615986]
Core was generated by `/home/pedro/gdb/build/gdb/testsuite/outputs/gdb.base/patch/patch'.
Program terminated with signal SIGTRAP, Trace/breakpoint trap.
#0 0x0000555555555131 in ?? ()
(gdb) p *(unsigned char *)0x0000555555555131 = 1
$1 = 1 '\001'
(gdb) p *(unsigned char *)0x0000555555555131
$2 = 185 '\271'
(gdb)
Diffing hexdumps of before/after patching, reveals that a "0x1" was
actually written somewhere in the file. The problem is that the "0x1"
was written at the wrong offset in the file...
That happens because _bfd_elf_set_section_contents does this to seek
to the section's offset:
pos = hdr->sh_offset + offset;
if (bfd_seek (abfd, pos, SEEK_SET) != 0
|| bfd_bwrite (location, count, abfd) != count)
return false;
... and 'hdr->sh_offset' is zero, so we seek to just OFFSET, which is
incorrect. The reason 'hdr->sh_offset' is zero is that
kernel-generated core files normally don't even have a section header
table (gdb-generated ones do, but that's more an accident than a
feature), and indeed elf_core_file_p doesn't even try to read sections
at all:
/* Core files are simply standard ELF formatted files that partition
the file using the execution view of the file (program header table)
rather than the linking view. In fact, there is no section header
table in a core file.
The process status information (including the contents of the general
register set) and the floating point register set are stored in a
segment of type PT_NOTE. We handcraft a couple of extra bfd sections
that allow standard bfd access to the general registers (.reg) and the
floating point registers (.reg2). */
bfd_cleanup
elf_core_file_p (bfd *abfd)
Changing _bfd_elf_set_section_contents from:
pos = hdr->sh_offset + offset;
to:
pos = section->filepos + offset;
fixes it. If we do that however, the tail end of
_bfd_elf_set_section_contents ends up as a copy of
_bfd_generic_set_section_contents, so just call the latter, thus
eliminating some duplicate code.
New GDB testcase included, which exercises both patching an executable
and patching a core file. Patching an executable already works
without this fix, because in that case BFD reads in the sections
table. Still, we had no testcase for that yet. In fact, we have no
"set write on" testcases at all, this is the first one.
Tested on x86-64 GNU/Linux, gdb, ld, binutils, and gas.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=18227
Change-Id: I0f49f58b48aabab2e269f2959b8fd8a7fe36fdce
This includes adding pseudosections when reading a core dump as well
as support for writing out a core dump note from a pseudosection.
bfd/ChangeLog:
* elf-bfd.h (elfcore_write_x86_segbases): New.
* elf.c (elfcore_grok_freebsd_note): Add pseudosections for
NT_FREEBSD_X86_SEGBASES register notes.
(elfcore_write_x86_segbases): New.
(elfcore_write_register_note): Write NT_FREEBSD_X86_SEGBASES
register notes.
