binutils-gdb/binutils/coffgrok.c
Nick Clifton 5b7d62376f This patch fixes some illegal memory accesses triggered by running coffdump on fuzzed binaries.
PR binutils/17512
	* coffgrok.c (do_type): Check that computed ref exists.
	(doit): Add range checks when computing section for scope.
2015-01-21 10:33:19 +00:00

872 lines
22 KiB
C

/* coffgrok.c
Copyright (C) 1994-2015 Free Software Foundation, Inc.
This file is part of GNU Binutils.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
/* Written by Steve Chamberlain (sac@cygnus.com)
This module reads a coff file and builds a really simple type tree
which can be read by other programs. The first application is a
coff->sysroff converter. It can be tested with coffdump.c. */
#include "sysdep.h"
#include "bfd.h"
#include "libiberty.h"
#include "coff/internal.h"
#include "../bfd/libcoff.h"
#include "bucomm.h"
#include "coffgrok.h"
static int lofile = 1;
static struct coff_scope * top_scope;
static struct coff_scope * file_scope;
static struct coff_ofile * ofile;
static struct coff_symbol * last_function_symbol;
static struct coff_type * last_function_type;
static struct coff_type * last_struct;
static struct coff_type * last_enum;
static struct coff_sfile * cur_sfile;
static struct coff_symbol ** tindex;
static asymbol ** syms;
static long symcount;
static struct coff_ptr_struct * rawsyms;
static unsigned int rawcount;
static bfd * abfd;
#define N(x) ((x)->_n._n_nptr[1])
#define PTR_SIZE 4
#define SHORT_SIZE 2
#define INT_SIZE 4
#define LONG_SIZE 4
#define FLOAT_SIZE 4
#define DOUBLE_SIZE 8
#define INDEXOF(p) ((struct coff_ptr_struct *)(p)-(rawsyms))
static struct coff_scope *
empty_scope (void)
{
return (struct coff_scope *) (xcalloc (sizeof (struct coff_scope), 1));
}
static struct coff_symbol *
empty_symbol (void)
{
return (struct coff_symbol *) (xcalloc (sizeof (struct coff_symbol), 1));
}
static void
push_scope (int slink)
{
struct coff_scope *n = empty_scope ();
if (slink)
{
if (top_scope)
{
if (top_scope->list_tail)
{
top_scope->list_tail->next = n;
}
else
{
top_scope->list_head = n;
}
top_scope->list_tail = n;
}
}
n->parent = top_scope;
top_scope = n;
}
static void
pop_scope (void)
{
/* PR 17512: file: 809933ac. */
if (top_scope == NULL)
fatal (_("Out of context scope change encountered"));
top_scope = top_scope->parent;
}
static void
do_sections_p1 (struct coff_ofile *head)
{
asection *section;
int idx;
struct coff_section *all = (struct coff_section *) (xcalloc (abfd->section_count + 1,
sizeof (struct coff_section)));
head->nsections = abfd->section_count + 1;
head->sections = all;
for (idx = 0, section = abfd->sections; section; section = section->next, idx++)
{
long relsize;
unsigned int i = section->target_index;
arelent **relpp;
long relcount;
/* PR 17512: file: 2d6effca. */
if (i > abfd->section_count)
fatal (_("Invalid section target index: %u"), i);
relsize = bfd_get_reloc_upper_bound (abfd, section);
if (relsize < 0)
bfd_fatal (bfd_get_filename (abfd));
if (relsize == 0)
continue;
relpp = (arelent **) xmalloc (relsize);
relcount = bfd_canonicalize_reloc (abfd, section, relpp, syms);
if (relcount < 0)
bfd_fatal (bfd_get_filename (abfd));
head->sections[i].name = (char *) (section->name);
head->sections[i].code = section->flags & SEC_CODE;
head->sections[i].data = section->flags & SEC_DATA;
if (strcmp (section->name, ".bss") == 0)
head->sections[i].data = 1;
head->sections[i].address = section->lma;
head->sections[i].size = bfd_get_section_size (section);
head->sections[i].number = idx;
head->sections[i].nrelocs = section->reloc_count;
head->sections[i].relocs =
(struct coff_reloc *) (xcalloc (section->reloc_count,
sizeof (struct coff_reloc)));
head->sections[i].bfd_section = section;
}
head->sections[0].name = "ABSOLUTE";
head->sections[0].code = 0;
head->sections[0].data = 0;
head->sections[0].address = 0;
head->sections[0].size = 0;
head->sections[0].number = 0;
}
static void
do_sections_p2 (struct coff_ofile *head)
{
asection *section;
for (section = abfd->sections; section; section = section->next)
{
unsigned int j;
/* PR 17512: file: 7c1a36e8.
A corrupt COFF binary might have a reloc count but no relocs.
Handle this here. */
if (section->relocation == NULL)
continue;
for (j = 0; j < section->reloc_count; j++)
{
unsigned int idx;
int i = section->target_index;
struct coff_reloc *r;
arelent *sr = section->relocation + j;
if (i > head->nsections)
fatal (_("Invalid section target index: %d"), i);
/* PR 17512: file: db850ff4. */
if (j >= head->sections[i].nrelocs)
fatal (_("Target section has insufficient relocs"));
r = head->sections[i].relocs + j;
r->offset = sr->address;
r->addend = sr->addend;
idx = ((coff_symbol_type *) (sr->sym_ptr_ptr[0]))->native - rawsyms;
if (idx >= rawcount)
{
if (rawcount == 0)
fatal (_("Symbol index %u encountered when there are no symbols"), idx);
non_fatal (_("Invalid symbol index %u encountered"), idx);
idx = 0;
}
r->symbol = tindex[idx];
}
}
}
static struct coff_where *
do_where (unsigned int i)
{
struct internal_syment *sym;
struct coff_where *where =
(struct coff_where *) (xmalloc (sizeof (struct coff_where)));
if (i >= rawcount)
fatal ("Invalid symbol index: %d\n", i);
sym = &rawsyms[i].u.syment;
where->offset = sym->n_value;
if (sym->n_scnum == -1)
sym->n_scnum = 0;
switch (sym->n_sclass)
{
case C_FIELD:
where->where = coff_where_member_of_struct;
where->offset = sym->n_value / 8;
where->bitoffset = sym->n_value % 8;
where->bitsize = rawsyms[i + 1].u.auxent.x_sym.x_misc.x_lnsz.x_size;
break;
case C_MOE:
where->where = coff_where_member_of_enum;
break;
case C_MOS:
case C_MOU:
where->where = coff_where_member_of_struct;
break;
case C_AUTO:
case C_ARG:
where->where = coff_where_stack;
break;
case C_EXT:
case C_STAT:
case C_EXTDEF:
case C_LABEL:
where->where = coff_where_memory;
/* PR 17512: file: 07a37c40. */
/* PR 17512: file: 0c2eb101. */
if (sym->n_scnum >= ofile->nsections || sym->n_scnum < 0)
{
non_fatal (_("Invalid section number (%d) encountered"),
sym->n_scnum);
where->section = ofile->sections;
}
else
where->section = &ofile->sections[sym->n_scnum];
break;
case C_REG:
case C_REGPARM:
where->where = coff_where_register;
break;
case C_ENTAG:
where->where = coff_where_entag;
break;
case C_STRTAG:
case C_UNTAG:
where->where = coff_where_strtag;
break;
case C_TPDEF:
where->where = coff_where_typedef;
break;
default:
fatal (_("Unrecognized symbol class: %d"), sym->n_sclass);
break;
}
return where;
}
static struct coff_line *
do_lines (int i, char *name ATTRIBUTE_UNUSED)
{
struct coff_line *res = (struct coff_line *) xcalloc (sizeof (struct coff_line), 1);
asection *s;
unsigned int l;
/* Find out if this function has any line numbers in the table. */
for (s = abfd->sections; s; s = s->next)
{
/* PR 17512: file: 07a37c40.
A corrupt COFF binary can have a linenumber count in the header
but no line number table. This should be reported elsewhere, but
do not rely upon this. */
if (s->lineno == NULL)
continue;
for (l = 0; l < s->lineno_count; l++)
{
if (s->lineno[l].line_number == 0)
{
if (rawsyms + i == ((coff_symbol_type *) (&(s->lineno[l].u.sym[0])))->native)
{
/* These lines are for this function - so count them and stick them on. */
int c = 0;
/* Find the linenumber of the top of the function, since coff linenumbers
are relative to the start of the function. */
int start_line = rawsyms[i + 3].u.auxent.x_sym.x_misc.x_lnsz.x_lnno;
l++;
for (c = 0;
/* PR 17512: file: c2825452. */
l + c + 1 < s->lineno_count
&& s->lineno[l + c + 1].line_number;
c++)
;
/* Add two extra records, one for the prologue and one for the epilogue. */
c += 1;
res->nlines = c;
res->lines = (int *) (xcalloc (sizeof (int), c));
res->addresses = (int *) (xcalloc (sizeof (int), c));
res->lines[0] = start_line;
res->addresses[0] = rawsyms[i].u.syment.n_value - s->vma;
for (c = 0;
/* PR 17512: file: c2825452. */
l + c + 1 < s->lineno_count
&& s->lineno[l + c + 1].line_number;
c++)
{
res->lines[c + 1] = s->lineno[l + c].line_number + start_line - 1;
res->addresses[c + 1] = s->lineno[l + c].u.offset;
}
return res;
}
}
}
}
return res;
}
static struct coff_type *
do_type (unsigned int i)
{
struct internal_syment *sym;
union internal_auxent *aux;
struct coff_type *res = (struct coff_type *) xmalloc (sizeof (struct coff_type));
int type;
int which_dt = 0;
int dimind = 0;
if (i >= rawcount)
fatal (_("Type entry %u does not have enough symbolic information"), i);
if (!rawsyms[i].is_sym)
fatal (_("Type entry %u does not refer to a symbol"), i);
sym = &rawsyms[i].u.syment;
if (sym->n_numaux == 0 || i >= rawcount -1 || rawsyms[i + 1].is_sym)
aux = NULL;
else
aux = &rawsyms[i + 1].u.auxent;
type = sym->n_type;
res->type = coff_basic_type;
res->u.basic = type & 0xf;
switch (type & 0xf)
{
case T_NULL:
case T_VOID:
if (sym->n_numaux && sym->n_sclass == C_STAT)
{
/* This is probably a section definition. */
res->type = coff_secdef_type;
if (aux == NULL)
fatal (_("Section definition needs a section length"));
res->size = aux->x_scn.x_scnlen;
/* PR 17512: file: 081c955d.
Fill in the asecdef structure as well. */
res->u.asecdef.address = 0;
res->u.asecdef.size = 0;
}
else
{
if (type == 0)
{
/* Don't know what this is, let's make it a simple int. */
res->size = INT_SIZE;
res->u.basic = T_UINT;
}
else
{
/* Else it could be a function or pointer to void. */
res->size = 0;
}
}
break;
case T_UCHAR:
case T_CHAR:
res->size = 1;
break;
case T_USHORT:
case T_SHORT:
res->size = SHORT_SIZE;
break;
case T_UINT:
case T_INT:
res->size = INT_SIZE;
break;
case T_ULONG:
case T_LONG:
res->size = LONG_SIZE;
break;
case T_FLOAT:
res->size = FLOAT_SIZE;
break;
case T_DOUBLE:
res->size = DOUBLE_SIZE;
break;
case T_STRUCT:
case T_UNION:
if (sym->n_numaux)
{
if (aux == NULL)
fatal (_("Aggregate definition needs auxillary information"));
if (aux->x_sym.x_tagndx.p)
{
unsigned int idx = INDEXOF (aux->x_sym.x_tagndx.p);
if (idx >= rawcount)
{
if (rawcount == 0)
fatal (_("Symbol index %u encountered when there are no symbols"), idx);
non_fatal (_("Invalid symbol index %u encountered"), idx);
idx = 0;
}
/* Referring to a struct defined elsewhere. */
res->type = coff_structref_type;
res->u.astructref.ref = tindex[idx];
res->size = res->u.astructref.ref ?
res->u.astructref.ref->type->size : 0;
}
else
{
/* A definition of a struct. */
last_struct = res;
res->type = coff_structdef_type;
res->u.astructdef.elements = empty_scope ();
res->u.astructdef.idx = 0;
res->u.astructdef.isstruct = (type & 0xf) == T_STRUCT;
res->size = aux->x_sym.x_misc.x_lnsz.x_size;
}
}
else
{
/* No auxents - it's anonymous. */
res->type = coff_structref_type;
res->u.astructref.ref = 0;
res->size = 0;
}
break;
case T_ENUM:
if (aux == NULL)
fatal (_("Enum definition needs auxillary information"));
if (aux->x_sym.x_tagndx.p)
{
unsigned int idx = INDEXOF (aux->x_sym.x_tagndx.p);
/* PR 17512: file: 1ef037c7. */
if (idx >= rawcount)
fatal (_("Invalid enum symbol index %u encountered"), idx);
/* Referring to a enum defined elsewhere. */
res->type = coff_enumref_type;
res->u.aenumref.ref = tindex[idx];
/* PR 17512: file: b85b67e8. */
if (res->u.aenumref.ref)
res->size = res->u.aenumref.ref->type->size;
else
res->size = 0;
}
else
{
/* A definition of an enum. */
last_enum = res;
res->type = coff_enumdef_type;
res->u.aenumdef.elements = empty_scope ();
res->size = aux->x_sym.x_misc.x_lnsz.x_size;
}
break;
case T_MOE:
break;
}
for (which_dt = 5; which_dt >= 0; which_dt--)
{
switch ((type >> ((which_dt * 2) + 4)) & 0x3)
{
case 0:
break;
case DT_ARY:
{
struct coff_type *ptr = ((struct coff_type *)
xmalloc (sizeof (struct coff_type)));
int els;
if (aux == NULL)
fatal (_("Array definition needs auxillary information"));
els = (dimind < DIMNUM
? aux->x_sym.x_fcnary.x_ary.x_dimen[dimind]
: 0);
++dimind;
ptr->type = coff_array_type;
ptr->size = els * res->size;
ptr->u.array.dim = els;
ptr->u.array.array_of = res;
res = ptr;
break;
}
case DT_PTR:
{
struct coff_type *ptr =
(struct coff_type *) xmalloc (sizeof (struct coff_type));
ptr->size = PTR_SIZE;
ptr->type = coff_pointer_type;
ptr->u.pointer.points_to = res;
res = ptr;
break;
}
case DT_FCN:
{
struct coff_type *ptr
= (struct coff_type *) xmalloc (sizeof (struct coff_type));
ptr->size = 0;
ptr->type = coff_function_type;
ptr->u.function.function_returns = res;
ptr->u.function.parameters = empty_scope ();
ptr->u.function.lines = do_lines (i, N(sym));
ptr->u.function.code = 0;
last_function_type = ptr;
res = ptr;
break;
}
}
}
return res;
}
static struct coff_visible *
do_visible (int i)
{
struct internal_syment *sym = &rawsyms[i].u.syment;
struct coff_visible *visible =
(struct coff_visible *) (xmalloc (sizeof (struct coff_visible)));
enum coff_vis_type t;
switch (sym->n_sclass)
{
case C_MOS:
case C_MOU:
case C_FIELD:
t = coff_vis_member_of_struct;
break;
case C_MOE:
t = coff_vis_member_of_enum;
break;
case C_REGPARM:
t = coff_vis_regparam;
break;
case C_REG:
t = coff_vis_register;
break;
case C_STRTAG:
case C_UNTAG:
case C_ENTAG:
case C_TPDEF:
t = coff_vis_tag;
break;
case C_AUTOARG:
case C_ARG:
t = coff_vis_autoparam;
break;
case C_AUTO:
t = coff_vis_auto;
break;
case C_LABEL:
case C_STAT:
t = coff_vis_int_def;
break;
case C_EXT:
if (sym->n_scnum == N_UNDEF)
{
if (sym->n_value)
t = coff_vis_common;
else
t = coff_vis_ext_ref;
}
else
t = coff_vis_ext_def;
break;
default:
fatal (_("Unrecognised symbol class: %d"), sym->n_sclass);
break;
}
visible->type = t;
return visible;
}
/* Define a symbol and attach to block B. */
static int
do_define (unsigned int i, struct coff_scope *b)
{
static int symbol_index;
struct internal_syment *sym;
struct coff_symbol *s = empty_symbol ();
if (b == NULL)
fatal (_("ICE: do_define called without a block"));
if (i >= rawcount)
fatal (_("Out of range symbol index: %u"), i);
sym = &rawsyms[i].u.syment;
s->number = ++symbol_index;
s->name = N(sym);
s->sfile = cur_sfile;
/* Glue onto the ofile list. */
if (lofile >= 0)
{
if (ofile->symbol_list_tail)
ofile->symbol_list_tail->next_in_ofile_list = s;
else
ofile->symbol_list_head = s;
ofile->symbol_list_tail = s;
/* And the block list. */
}
if (b->vars_tail)
b->vars_tail->next = s;
else
b->vars_head = s;
b->vars_tail = s;
b->nvars++;
s->type = do_type (i);
s->where = do_where (i);
s->visible = do_visible (i);
tindex[i] = s;
/* We remember the lowest address in each section for each source file. */
if (s->where->where == coff_where_memory
&& s->type->type == coff_secdef_type)
{
struct coff_isection *is;
/* PR 17512: file: 4676c97f. */
if (cur_sfile == NULL)
non_fatal (_("Section referenced before any file is defined"));
else
{
is = cur_sfile->section + s->where->section->number;
if (!is->init)
{
is->low = s->where->offset;
is->high = s->where->offset + s->type->size;
is->init = 1;
is->parent = s->where->section;
}
}
}
if (s->type->type == coff_function_type)
last_function_symbol = s;
return i + sym->n_numaux + 1;
}
static struct coff_ofile *
doit (void)
{
unsigned int i;
bfd_boolean infile = FALSE;
struct coff_ofile *head =
(struct coff_ofile *) xmalloc (sizeof (struct coff_ofile));
ofile = head;
head->source_head = 0;
head->source_tail = 0;
head->nsources = 0;
head->symbol_list_tail = 0;
head->symbol_list_head = 0;
do_sections_p1 (head);
push_scope (1);
for (i = 0; i < rawcount;)
{
struct internal_syment *sym = &rawsyms[i].u.syment;
switch (sym->n_sclass)
{
case C_FILE:
{
/* New source file announced. */
struct coff_sfile *n =
(struct coff_sfile *) xmalloc (sizeof (struct coff_sfile));
n->section = (struct coff_isection *) xcalloc (sizeof (struct coff_isection), abfd->section_count + 1);
cur_sfile = n;
n->name = N(sym);
n->next = 0;
if (infile)
pop_scope ();
else
infile = TRUE;
push_scope (1);
file_scope = n->scope = top_scope;
if (head->source_tail)
head->source_tail->next = n;
else
head->source_head = n;
head->source_tail = n;
head->nsources++;
i += sym->n_numaux + 1;
}
break;
case C_FCN:
{
char *name = N(sym);
if (name[1] == 'b')
{
/* Function start. */
push_scope (0);
/* PR 17512: file: 0ef7fbaf. */
if (last_function_type)
last_function_type->u.function.code = top_scope;
/* PR 17512: file: 22908266. */
if (sym->n_scnum < ofile->nsections && sym->n_scnum >= 0)
top_scope->sec = ofile->sections + sym->n_scnum;
else
top_scope->sec = NULL;
top_scope->offset = sym->n_value;
}
else
{
/* PR 17512: file: e92e42e1. */
if (top_scope == NULL)
fatal (_("Function start encountered without a top level scope."));
top_scope->size = sym->n_value - top_scope->offset + 1;
pop_scope ();
}
i += sym->n_numaux + 1;
}
break;
case C_BLOCK:
{
char *name = N(sym);
if (name[1] == 'b')
{
/* Block start. */
push_scope (1);
/* PR 17512: file: af7e8e83. */
if (sym->n_scnum < ofile->nsections && sym->n_scnum >= 0)
top_scope->sec = ofile->sections + sym->n_scnum;
else
top_scope->sec = NULL;
top_scope->offset = sym->n_value;
}
else
{
if (top_scope == NULL)
fatal (_("Block start encountered without a scope for it."));
top_scope->size = sym->n_value - top_scope->offset + 1;
pop_scope ();
}
i += sym->n_numaux + 1;
}
break;
case C_REGPARM:
case C_ARG:
if (last_function_symbol == NULL)
fatal (_("Function arguments encountered without a function definition"));
i = do_define (i, last_function_symbol->type->u.function.parameters);
break;
case C_MOS:
case C_MOU:
case C_FIELD:
/* PR 17512: file: 43ab21f4. */
if (last_struct == NULL)
fatal (_("Structure element encountered without a structure definition"));
i = do_define (i, last_struct->u.astructdef.elements);
break;
case C_MOE:
if (last_enum == NULL)
fatal (_("Enum element encountered without an enum definition"));
i = do_define (i, last_enum->u.aenumdef.elements);
break;
case C_STRTAG:
case C_ENTAG:
case C_UNTAG:
/* Various definition. */
if (top_scope == NULL)
fatal (_("Aggregate defintion encountered without a scope"));
i = do_define (i, top_scope);
break;
case C_EXT:
case C_LABEL:
if (file_scope == NULL)
fatal (_("Label defintion encountered without a file scope"));
i = do_define (i, file_scope);
break;
case C_STAT:
case C_TPDEF:
case C_AUTO:
case C_REG:
if (top_scope == NULL)
fatal (_("Variable defintion encountered without a scope"));
i = do_define (i, top_scope);
break;
case C_EOS:
i += sym->n_numaux + 1;
break;
default:
fatal (_("Unrecognised symbol class: %d"), sym->n_sclass);
}
}
do_sections_p2 (head);
return head;
}
struct coff_ofile *
coff_grok (bfd *inabfd)
{
long storage;
struct coff_ofile *p;
abfd = inabfd;
if (! bfd_family_coff (abfd))
{
non_fatal (_("%s: is not a COFF format file"), bfd_get_filename (abfd));
return NULL;
}
storage = bfd_get_symtab_upper_bound (abfd);
if (storage < 0)
bfd_fatal (abfd->filename);
syms = (asymbol **) xmalloc (storage);
symcount = bfd_canonicalize_symtab (abfd, syms);
if (symcount < 0)
bfd_fatal (abfd->filename);
rawsyms = obj_raw_syments (abfd);
rawcount = obj_raw_syment_count (abfd);
tindex = (struct coff_symbol **) (xcalloc (sizeof (struct coff_symbol *), rawcount));
p = doit ();
return p;
}