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PR24891, objdump memory leaks when parsing malformed archive

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BFD was leaking memory in bfd_check_format_matches.  As part of
deciding the proper format of an archive, BFD looks at the format of
the first file stored.  That file's bfd was left open for reasons
given in a comment removed in git commit 0e71e4955c that said:
             /* We ought to close `first' here, but we can't, because
                we have no way to remove it from the archive cache.
                It's close to impossible to figure out when we can
                release bfd_ardata.  FIXME.  */
Well, things have changed since that comment was true and we now can
remove files from the archive cache.  Closing the first file is good
and cures some of the leaks.  Other leaks are caused by
bfd_check_format_matches throwing away bfd tdata before trying a new
match.  That lost the element cache set up when format checking the
first element in the archive.  The easiest and cleanest fix is to
simply disable the caching when checking the first element.

	PR 24891
	* bfd.c (struct bfd): Add no_element_cache.
	* archive.c (_bfd_get_elt_at_filepos): Don't add element to
	archive cache when no_element_cache.
	(bfd_generic_archive_p): Set no_element_cache when opening first
	element to check format.  Close first element too.
	(do_slurp_bsd_armap): Don't zero ardata->cache here.
	* bfd-in2.h: Regenerate.
This commit is contained in:
Alan Modra 2019-08-28 16:34:34 +09:30
parent 48352473b1
commit 83cf0d04dc
4 changed files with 24 additions and 3 deletions
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11
bfd/ChangeLog
View file

@ -1,3 +1,14 @@
2019-08-29 Alan Modra <amodra@gmail.com>
PR 24891
* bfd.c (struct bfd): Add no_element_cache.
* archive.c (_bfd_get_elt_at_filepos): Don't add element to
archive cache when no_element_cache.
(bfd_generic_archive_p): Set no_element_cache when opening first
element to check format. Close first element too.
(do_slurp_bsd_armap): Don't zero ardata->cache here.
* bfd-in2.h: Regenerate.
2019-08-24 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (ppc64_elf_edit_toc): Exclude undefined weak

10
bfd/archive.c
View file

@ -734,7 +734,8 @@ _bfd_get_elt_at_filepos (bfd *archive, file_ptr filepos)
/* Copy is_linker_input. */
n_bfd->is_linker_input = archive->is_linker_input;
if (_bfd_add_bfd_to_archive_cache (archive, filepos, n_bfd))
if (archive->no_element_cache
|| _bfd_add_bfd_to_archive_cache (archive, filepos, n_bfd))
return n_bfd;
free (new_areldata);
@ -885,6 +886,7 @@ bfd_generic_archive_p (bfd *abfd)
if (abfd->target_defaulted && bfd_has_map (abfd))
{
bfd *first;
unsigned int save;
/* This archive has a map, so we may presume that the contents
are object files. Make sure that if the first file in the
@ -897,14 +899,17 @@ bfd_generic_archive_p (bfd *abfd)
normal archive, regardless of the format of the object files.
We do accept an empty archive. */
save = abfd->no_element_cache;
abfd->no_element_cache = 1;
first = bfd_openr_next_archived_file (abfd, NULL);
abfd->no_element_cache = save;
if (first != NULL)
{
first->target_defaulted = FALSE;
if (bfd_check_format (first, bfd_object)
&& first->xvec != abfd->xvec)
bfd_set_error (bfd_error_wrong_object_format);
/* And we ought to close `first' here too. */
bfd_close (first);
}
}
@ -974,7 +979,6 @@ do_slurp_bsd_armap (bfd *abfd)
goto byebye;
}
ardata->cache = 0;
rbase = raw_armap + BSD_SYMDEF_COUNT_SIZE;
stringbase = ((char *) rbase
+ ardata->symdef_count * BSD_SYMDEF_SIZE

3
bfd/bfd-in2.h
View file

@ -7180,6 +7180,9 @@ struct bfd
/* Set if this is a thin archive. */
unsigned int is_thin_archive : 1;
/* Set if this archive should not cache element positions. */
unsigned int no_element_cache : 1;
/* Set if only required symbols should be added in the link hash table for
this object. Used by VMS linkers. */
unsigned int selective_search : 1;

3
bfd/bfd.c
View file

@ -220,6 +220,9 @@ CODE_FRAGMENT
. {* Set if this is a thin archive. *}
. unsigned int is_thin_archive : 1;
.
. {* Set if this archive should not cache element positions. *}
. unsigned int no_element_cache : 1;
.
. {* Set if only required symbols should be added in the link hash table for
. this object. Used by VMS linkers. *}
. unsigned int selective_search : 1;