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More fixes for buffer overruns instigated by corrupt binaries.

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PR binutils/17512
	* objdump.c (slurp_symtab): Fail gracefully if the table could not
	be read.
	(dump_relocs_in_section): Likewise.

	* aoutx.h (slurp_symbol_table): Check that computed table size is
	not bigger than the file from which is it being read.
	(slurp_reloc_table): Likewise.
	* coffcode.h (coff_slurp_line_table): Remove unneeded local
	'warned'.  Do not try to print the details of a symbol with an
	invalid index.
	* coffgen.c (make_a_sectiobn_from_file): Check computed string
	index against length of string table.
	(bfd_coff_internal_syment_name): Check read in string offset
	against length of string table.
	(build_debug_section): Return a pointer to the section used.
	(_bfd_coff_read_string_table): Store the length of the string
	table in the coff_tdata structure.
	(bfd_coff_free_symbols): Set the length of the string table to
	zero when it is freed.
	(coff_get_normalized_symtab): Check offsets against string table
	or data table lengths as appropriate.
	* cofflink.c (_bfd_coff_link_input_bfd): Check offset against
	length of string table.
	* compress.c (bfd_get_full_section_contents): Check computed size
	against the size of the file.
	* libcoff-in.h (obj_coff_strings_len): Define.
	(struct coff_tdata): Add strings_len field.
	* libcoff.h: Regenerate.
	* peXXigen.c (pe_print_debugdata): Do not attempt to print the
	data if the debug section is too small.
	* xcofflink.c (xcoff_link_input_bfd):  Check offset against
	length of string table.
This commit is contained in:
Nick Clifton 2014-11-03 17:44:00 +00:00
parent ba241f2d5a
commit 5a3f568b70
12 changed files with 140 additions and 32 deletions
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32
bfd/ChangeLog
View File

@ -1,3 +1,35 @@
2014-11-03 Nick Clifton <nickc@redhat.com>
PR binutils/17512
* aoutx.h (slurp_symbol_table): Check that computed table size is
not bigger than the file from which is it being read.
(slurp_reloc_table): Likewise.
* coffcode.h (coff_slurp_line_table): Remove unneeded local
'warned'. Do not try to print the details of a symbol with an
invalid index.
* coffgen.c (make_a_sectiobn_from_file): Check computed string
index against length of string table.
(bfd_coff_internal_syment_name): Check read in string offset
against length of string table.
(build_debug_section): Return a pointer to the section used.
(_bfd_coff_read_string_table): Store the length of the string
table in the coff_tdata structure.
(bfd_coff_free_symbols): Set the length of the string table to
zero when it is freed.
(coff_get_normalized_symtab): Check offsets against string table
or data table lengths as appropriate.
* cofflink.c (_bfd_coff_link_input_bfd): Check offset against
length of string table.
* compress.c (bfd_get_full_section_contents): Check computed size
against the size of the file.
* libcoff-in.h (obj_coff_strings_len): Define.
(struct coff_tdata): Add strings_len field.
* libcoff.h: Regenerate.
* peXXigen.c (pe_print_debugdata): Do not attempt to print the
data if the debug section is too small.
* xcofflink.c (xcoff_link_input_bfd): Check offset against
length of string table.
2014-11-03 Nick Clifton <nickc@redhat.com>
* po/fi.po: Updated Finnish translation.

7
bfd/aoutx.h
View File

@ -1756,6 +1756,8 @@ NAME (aout, slurp_symbol_table) (bfd *abfd)
return TRUE; /* Nothing to do. */
cached_size *= sizeof (aout_symbol_type);
if (cached_size >= (bfd_size_type) bfd_get_size (abfd))
return FALSE;
cached = (aout_symbol_type *) bfd_zmalloc (cached_size);
if (cached == NULL)
return FALSE;
@ -2307,6 +2309,11 @@ NAME (aout, slurp_reloc_table) (bfd *abfd, sec_ptr asect, asymbol **symbols)
if (reloc_size == 0)
return TRUE; /* Nothing to be done. */
/* PR binutils/17512: Do not even try to
load the relocs if their size is corrupt. */
if (reloc_size + asect->rel_filepos >= (bfd_size_type) bfd_get_size (abfd))
return FALSE;
if (bfd_seek (abfd, asect->rel_filepos, SEEK_SET) != 0)
return FALSE;

11
bfd/coffcode.h
View File

@ -4546,21 +4546,18 @@ coff_slurp_line_table (bfd *abfd, asection *asect)
if (cache_ptr->line_number == 0)
{
bfd_boolean warned;
bfd_signed_vma symndx;
coff_symbol_type *sym;
nbr_func++;
warned = FALSE;
symndx = dst.l_addr.l_symndx;
if (symndx < 0
|| (bfd_vma) symndx >= obj_raw_syment_count (abfd))
{
(*_bfd_error_handler)
(_("%B: warning: illegal symbol index %ld in line numbers"),
abfd, (long) symndx);
symndx = 0;
warned = TRUE;
(_("%B: warning: illegal symbol index 0x%lx in line number entry %d"),
abfd, (long) symndx, counter);
continue;
}
/* FIXME: We should not be casting between ints and
@ -4569,7 +4566,7 @@ coff_slurp_line_table (bfd *abfd, asection *asect)
((symndx + obj_raw_syments (abfd))
->u.syment._n._n_n._n_zeroes));
cache_ptr->u.sym = (asymbol *) sym;
if (sym->lineno != NULL && ! warned)
if (sym->lineno != NULL)
(*_bfd_error_handler)
(_("%B: warning: duplicate line number information for `%s'"),
abfd, bfd_asymbol_name (&sym->symbol));

54
bfd/coffgen.c
View File

@ -84,9 +84,8 @@ make_a_section_from_file (bfd *abfd,
strings = _bfd_coff_read_string_table (abfd);
if (strings == NULL)
return FALSE;
/* FIXME: For extra safety, we should make sure that
strindex does not run us past the end, but right now we
don't know the length of the string table. */
if ((bfd_size_type)(strindex + 2) >= obj_coff_strings_len (abfd))
return FALSE;
strings += strindex;
name = (char *) bfd_alloc (abfd,
(bfd_size_type) strlen (strings) + 1 + 1);
@ -464,6 +463,8 @@ _bfd_coff_internal_syment_name (bfd *abfd,
if (strings == NULL)
return NULL;
}
if (sym->_n._n_n._n_offset >= obj_coff_strings_len (abfd))
return NULL;
return strings + sym->_n._n_n._n_offset;
}
}
@ -1545,7 +1546,7 @@ coff_pointerize_aux (bfd *abfd,
we didn't want to go to the trouble until someone needed it. */
static char *
build_debug_section (bfd *abfd)
build_debug_section (bfd *abfd, asection ** sect_return)
{
char *debug_section;
file_ptr position;
@ -1573,6 +1574,8 @@ build_debug_section (bfd *abfd)
|| bfd_bread (debug_section, sec_size, abfd) != sec_size
|| bfd_seek (abfd, position, SEEK_SET) != 0)
return NULL;
* sect_return = sect;
return debug_section;
}
@ -1640,7 +1643,9 @@ _bfd_coff_get_external_symbols (bfd *abfd)
/* Read in the external strings. The strings are not loaded until
they are needed. This is because we have no simple way of
detecting a missing string table in an archive. */
detecting a missing string table in an archive. If the strings
are loaded then the STRINGS and STRINGS_LEN fields in the
coff_tdata structure will be set. */
const char *
_bfd_coff_read_string_table (bfd *abfd)
@ -1702,6 +1707,7 @@ _bfd_coff_read_string_table (bfd *abfd)
}
obj_coff_strings (abfd) = strings;
obj_coff_strings_len (abfd) = strsize;
return strings;
}
@ -1722,6 +1728,7 @@ _bfd_coff_free_symbols (bfd *abfd)
{
free (obj_coff_strings (abfd));
obj_coff_strings (abfd) = NULL;
obj_coff_strings_len (abfd) = 0;
}
return TRUE;
}
@ -1742,13 +1749,22 @@ coff_get_normalized_symtab (bfd *abfd)
char *raw_src;
char *raw_end;
const char *string_table = NULL;
char *debug_section = NULL;
asection * debug_sec = NULL;
char *debug_sec_data = NULL;
bfd_size_type size;
if (obj_raw_syments (abfd) != NULL)
return obj_raw_syments (abfd);
size = obj_raw_syment_count (abfd) * sizeof (combined_entry_type);
size = obj_raw_syment_count (abfd);
if (size == 0)
return NULL;
/* PR binutils/17512: Do not even try to load
a symbol table bigger than the entire file... */
if (size >= (bfd_size_type) bfd_get_size (abfd))
return NULL;
size *= sizeof (combined_entry_type);
internal = (combined_entry_type *) bfd_zalloc (abfd, size);
if (internal == NULL && size != 0)
return NULL;
@ -1819,7 +1835,10 @@ coff_get_normalized_symtab (bfd *abfd)
if (string_table == NULL)
return NULL;
}
if ((bfd_size_type)((internal_ptr + 1)->u.auxent.x_file.x_n.x_offset)
>= obj_coff_strings_len (abfd))
internal_ptr->u.syment._n._n_n._n_offset = (bfd_hostptr_t) _("<corrupt>");
else
internal_ptr->u.syment._n._n_n._n_offset =
((bfd_hostptr_t)
(string_table
@ -1878,6 +1897,9 @@ coff_get_normalized_symtab (bfd *abfd)
if (string_table == NULL)
return NULL;
}
if (internal_ptr->u.syment._n._n_n._n_offset >= obj_coff_strings_len (abfd))
internal_ptr->u.syment._n._n_n._n_offset = (bfd_hostptr_t) _("<corrupt>");
else
internal_ptr->u.syment._n._n_n._n_offset =
((bfd_hostptr_t)
(string_table
@ -1886,10 +1908,20 @@ coff_get_normalized_symtab (bfd *abfd)
else
{
/* Long name in debug section. Very similar. */
if (debug_section == NULL)
debug_section = build_debug_section (abfd);
if (debug_sec_data == NULL)
debug_sec_data = build_debug_section (abfd, & debug_sec);
if (debug_sec_data != NULL)
{
BFD_ASSERT (debug_sec != NULL);
/* PR binutils/17512: Catch out of range offsets into the debug data. */
if (internal_ptr->u.syment._n._n_n._n_offset > debug_sec->size)
internal_ptr->u.syment._n._n_n._n_offset = (bfd_hostptr_t) _("<corrupt>");
else
internal_ptr->u.syment._n._n_n._n_offset = (bfd_hostptr_t)
(debug_section + internal_ptr->u.syment._n._n_n._n_offset);
(debug_sec_data + internal_ptr->u.syment._n._n_n._n_offset);
}
else
internal_ptr->u.syment._n._n_n._n_offset = (bfd_hostptr_t) "";
}
}
internal_ptr += internal_ptr->u.syment.n_numaux;

3
bfd/cofflink.c
View File

@ -2003,6 +2003,9 @@ _bfd_coff_link_input_bfd (struct coff_final_link_info *flaginfo, bfd *input_bfd)
if (strings == NULL)
return FALSE;
}
if ((bfd_size_type) auxp->x_file.x_n.x_offset >= obj_coff_strings_len (input_bfd))
filename = _("<corrupt>");
else
filename = strings + auxp->x_file.x_n.x_offset;
indx = _bfd_stringtab_add (flaginfo->strtab, filename,
hash, copy);

7
bfd/compress.c
View File

@ -177,6 +177,13 @@ bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
switch (sec->compress_status)
{
case COMPRESS_SECTION_NONE:
/* PR binutils/17512: Avoid malloc or file reading errors due to
ridiculous section sizes. But ignore linker created objects
with no contents (yet). */
if (bfd_get_size (abfd) > 0
&& sz > (bfd_size_type) bfd_get_size (abfd))
return FALSE;
if (p == NULL)
{
p = (bfd_byte *) bfd_malloc (sz);

3
bfd/libcoff-in.h
View File

@ -35,6 +35,7 @@
#define obj_coff_external_syms(bfd) (coff_data (bfd)->external_syms)
#define obj_coff_keep_syms(bfd) (coff_data (bfd)->keep_syms)
#define obj_coff_strings(bfd) (coff_data (bfd)->strings)
#define obj_coff_strings_len(bfd) (coff_data (bfd)->strings_len)
#define obj_coff_keep_strings(bfd) (coff_data (bfd)->keep_strings)
#define obj_coff_sym_hashes(bfd) (coff_data (bfd)->sym_hashes)
#define obj_coff_strings_written(bfd) (coff_data (bfd)->strings_written)
@ -75,6 +76,8 @@ typedef struct coff_tdata
/* The string table. May be NULL. Read by
_bfd_coff_read_string_table. */
char *strings;
/* The length of the strings table. For error checking. */
bfd_size_type strings_len;
/* If this is TRUE, the strings may not be freed. */
bfd_boolean keep_strings;
/* If this is TRUE, the strings have been written out already. */

3
bfd/libcoff.h
View File

@ -39,6 +39,7 @@
#define obj_coff_external_syms(bfd) (coff_data (bfd)->external_syms)
#define obj_coff_keep_syms(bfd) (coff_data (bfd)->keep_syms)
#define obj_coff_strings(bfd) (coff_data (bfd)->strings)
#define obj_coff_strings_len(bfd) (coff_data (bfd)->strings_len)
#define obj_coff_keep_strings(bfd) (coff_data (bfd)->keep_strings)
#define obj_coff_sym_hashes(bfd) (coff_data (bfd)->sym_hashes)
#define obj_coff_strings_written(bfd) (coff_data (bfd)->strings_written)
@ -79,6 +80,8 @@ typedef struct coff_tdata
/* The string table. May be NULL. Read by
_bfd_coff_read_string_table. */
char *strings;
/* The length of the strings table. For error checking. */
bfd_size_type strings_len;
/* If this is TRUE, the strings may not be freed. */
bfd_boolean keep_strings;
/* If this is TRUE, the strings have been written out already. */

7
bfd/peXXigen.c
View File

@ -2514,6 +2514,13 @@ pe_print_debugdata (bfd * abfd, void * vfile)
section->name);
return TRUE;
}
else if (section->size < size)
{
fprintf (file,
_("\nError: section %s contains the debug data starting address but it is too small\n"),
section->name);
return FALSE;
}
fprintf (file, _("\nThere is a debug directory in %s at 0x%lx\n\n"),
section->name, (unsigned long) addr);

3
bfd/xcofflink.c
View File

@ -4494,6 +4494,9 @@ xcoff_link_input_bfd (struct xcoff_final_link_info *flinfo,
if (strings == NULL)
return FALSE;
}
if ((bfd_size_type) aux.x_file.x_n.x_offset >= obj_coff_strings_len (input_bfd))
filename = _("<corrupt>");
else
filename = strings + aux.x_file.x_n.x_offset;
indx = _bfd_stringtab_add (flinfo->strtab, filename,
hash, copy);

7
binutils/ChangeLog
View File

@ -1,3 +1,10 @@
2014-11-03 Nick Clifton <nickc@redhat.com>
PR binutils/17512
* objdump.c (slurp_symtab): Fail gracefully if the table could not
be read.
(dump_relocs_in_section): Likewise.
2014-11-03 Nick Clifton <nickc@redhat.com>
* po/fi.po: Updated Finnish translation.

11
binutils/objdump.c
View File

@ -562,7 +562,10 @@ slurp_symtab (bfd *abfd)
storage = bfd_get_symtab_upper_bound (abfd);
if (storage < 0)
bfd_fatal (bfd_get_filename (abfd));
{
non_fatal (_("failed to read symbol table from: %s"), bfd_get_filename (abfd));
bfd_fatal (_("error message was"));
}
if (storage)
sy = (asymbol **) xmalloc (storage);
@ -3108,7 +3111,11 @@ dump_relocs_in_section (bfd *abfd,
relcount = bfd_canonicalize_reloc (abfd, section, relpp, syms);
if (relcount < 0)
bfd_fatal (bfd_get_filename (abfd));
{
printf ("\n");
non_fatal (_("failed to read relocs in: %s"), bfd_get_filename (abfd));
bfd_fatal (_("error message was"));
}
else if (relcount == 0)
printf (" (none)\n\n");
else