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PR 21274, ld segfaults linking PE DLL 

Don't use fixed size buffers for symbol names.

	PR 21274
	PR 18466
	* emultempl/pe.em (pe_find_data_imports): Don't use fixed size
	symbol buffer.  Instead, xmalloc max size needed with space for
	prefix.  Wrap overlong lines.  Formatting.  Pass symbol buffer
	copy of name to pe_walk_relocs_of_symbol.
	(make_inport_fixup): Add "name" param, pass to pe_create_import_fixup.
	* emultempl/pe.em (pep_find_data_imports): As for pe_find_data_imports.
	(make_import_fixup): Add "name" param, pass to pep_create_import_fixup.
	Use bfd_get_signed_* and remove unnecessary casts.  Formatting.
	* pe-dll.c (pe_walk_relocs_of_symbol): Add "name" param.  Pass to
	callback.
	(make_import_fixup_mark): Add "name" param.  Make use of prefix
	space rather than xmalloc here.
	(pe_create_import_fixup): Likewise.
	* pe-dll.h (pe_walk_relocs_of_symbol): Update prototype.
	(pe_create_import_fixup): Likewise.
	* pep-dll.h (pep_walk_relocs_of_symbol): Likewise.
	(pep_create_import_fixup): Likewise.
This commit is contained in:
Alan Modra 2017-04-11 19:37:51 +09:30
parent b43c520dba
commit fbea15088d
6 changed files with 155 additions and 114 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
ld/ChangeLog
View File

@ -1,3 +1,25 @@
2017-04-11 Alan Modra <amodra@gmail.com>
PR 21274
PR 18466
* emultempl/pe.em (pe_find_data_imports): Don't use fixed size
symbol buffer. Instead, xmalloc max size needed with space for
prefix. Wrap overlong lines. Formatting. Pass symbol buffer
copy of name to pe_walk_relocs_of_symbol.
(make_inport_fixup): Add "name" param, pass to pe_create_import_fixup.
* emultempl/pe.em (pep_find_data_imports): As for pe_find_data_imports.
(make_import_fixup): Add "name" param, pass to pep_create_import_fixup.
Use bfd_get_signed_* and remove unnecessary casts. Formatting.
* pe-dll.c (pe_walk_relocs_of_symbol): Add "name" param. Pass to
callback.
(make_import_fixup_mark): Add "name" param. Make use of prefix
space rather than xmalloc here.
(pe_create_import_fixup): Likewise.
* pe-dll.h (pe_walk_relocs_of_symbol): Update prototype.
(pe_create_import_fixup): Likewise.
* pep-dll.h (pep_walk_relocs_of_symbol): Likewise.
(pep_create_import_fixup): Likewise.
2017-04-10 Nick Clifton <nickc@redhat.com>
* ld.texinfo (--strip-discarded): Document.

64
ld/emultempl/pe.em
View File

@ -1130,7 +1130,7 @@ pe_fixup_stdcalls (void)
}
static int
make_import_fixup (arelent *rel, asection *s)
make_import_fixup (arelent *rel, asection *s, char *name)
{
struct bfd_symbol *sym = *rel->sym_ptr_ptr;
char addend[4];
@ -1143,7 +1143,7 @@ make_import_fixup (arelent *rel, asection *s)
einfo (_("%C: Cannot get section contents - auto-import exception\n"),
s->owner, s, rel->address);
pe_create_import_fixup (rel, s, bfd_get_32 (s->owner, addend));
pe_create_import_fixup (rel, s, bfd_get_32 (s->owner, addend), name);
return 1;
}
@ -1152,32 +1152,46 @@ static void
pe_find_data_imports (void)
{
struct bfd_link_hash_entry *undef, *sym;
size_t namelen;
char *buf, *name;
if (link_info.pei386_auto_import == 0)
return;
for (undef = link_info.hash->undefs; undef; undef=undef->u.undef.next)
namelen = 0;
for (undef = link_info.hash->undefs; undef; undef = undef->u.undef.next)
{
if (undef->type == bfd_link_hash_undefined)
{
/* C++ symbols are *long*. */
#define BUF_SIZE 4096
char buf[BUF_SIZE];
size_t len = strlen (undef->root.string);
if (namelen < len)
namelen = len;
}
}
if (namelen == 0)
return;
/* We are being a bit cunning here. The buffer will have space for
prefixes at the beginning. The prefix is modified here and in a
number of functions called from this function. */
#define PREFIX_LEN 32
buf = xmalloc (PREFIX_LEN + namelen + 1);
name = buf + PREFIX_LEN;
for (undef = link_info.hash->undefs; undef; undef = undef->u.undef.next)
{
if (undef->type == bfd_link_hash_undefined)
{
char *impname;
if (pe_dll_extra_pe_debug)
printf ("%s:%s\n", __FUNCTION__, undef->root.string);
if (strlen (undef->root.string) > (BUF_SIZE - 6))
{
/* PR linker/18466. */
einfo (_("%P: internal error: symbol too long: %s\n"),
undef->root.string);
return;
}
strcpy (name, undef->root.string);
impname = name - (sizeof "__imp_" - 1);
memcpy (impname, "__imp_", sizeof "__imp_" - 1);
sprintf (buf, "__imp_%s", undef->root.string);
sym = bfd_link_hash_lookup (link_info.hash, buf, 0, 0, 1);
sym = bfd_link_hash_lookup (link_info.hash, impname, 0, 0, 1);
if (sym && sym->type == bfd_link_hash_defined)
{
@ -1189,15 +1203,18 @@ pe_find_data_imports (void)
{
static bfd_boolean warned = FALSE;
info_msg (_("Info: resolving %s by linking to %s (auto-import)\n"),
undef->root.string, buf);
info_msg (_("Info: resolving %s by linking to %s "
"(auto-import)\n"), name, impname);
/* PR linker/4844. */
if (! warned)
{
warned = TRUE;
einfo (_("%P: warning: auto-importing has been activated without --enable-auto-import specified on the command line.\n\
This should work unless it involves constant data structures referencing symbols from auto-imported DLLs.\n"));
einfo (_("%P: warning: auto-importing has been activated "
"without --enable-auto-import specified on the "
"command line.\nThis should work unless it "
"involves constant data structures referencing "
"symbols from auto-imported DLLs.\n"));
}
}
@ -1212,8 +1229,7 @@ This should work unless it involves constant data structures referencing symbols
for (i = 0; i < nsyms; i++)
{
if (! CONST_STRNEQ (symbols[i]->name,
U ("_head_")))
if (! CONST_STRNEQ (symbols[i]->name, U ("_head_")))
continue;
if (pe_dll_extra_pe_debug)
@ -1224,8 +1240,7 @@ This should work unless it involves constant data structures referencing symbols
break;
}
pe_walk_relocs_of_symbol (&link_info, undef->root.string,
make_import_fixup);
pe_walk_relocs_of_symbol (&link_info, name, make_import_fixup);
/* Let's differentiate it somehow from defined. */
undef->type = bfd_link_hash_defweak;
@ -1238,6 +1253,7 @@ This should work unless it involves constant data structures referencing symbols
}
}
}
free (buf);
}
static bfd_boolean

116
ld/emultempl/pep.em
View File

@ -1075,7 +1075,7 @@ pep_fixup_stdcalls (void)
}
static int
make_import_fixup (arelent *rel, asection *s)
make_import_fixup (arelent *rel, asection *s, char *name)
{
struct bfd_symbol *sym = *rel->sym_ptr_ptr;
char addend[8];
@ -1089,32 +1089,32 @@ make_import_fixup (arelent *rel, asection *s)
memset (addend, 0, sizeof (addend));
switch ((rel->howto->bitsize))
{
case 8:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 1);
if (suc && rel->howto->pc_relative)
_addend = (bfd_vma) ((bfd_signed_vma) ((char) bfd_get_8 (s->owner, addend)));
else if (suc)
_addend = ((bfd_vma) bfd_get_8 (s->owner, addend)) & 0xff;
break;
case 16:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 2);
if (suc && rel->howto->pc_relative)
_addend = (bfd_vma) ((bfd_signed_vma) ((short) bfd_get_16 (s->owner, addend)));
else if (suc)
_addend = ((bfd_vma) bfd_get_16 (s->owner, addend)) & 0xffff;
break;
case 32:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 4);
if (suc && rel->howto->pc_relative)
_addend = (bfd_vma) ((bfd_signed_vma) ((int) bfd_get_32 (s->owner, addend)));
else if (suc)
_addend = ((bfd_vma) bfd_get_32 (s->owner, addend)) & 0xffffffff;
break;
case 64:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 8);
if (suc)
_addend = ((bfd_vma) bfd_get_64 (s->owner, addend));
break;
case 8:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 1);
if (suc && rel->howto->pc_relative)
_addend = bfd_get_signed_8 (s->owner, addend);
else if (suc)
_addend = bfd_get_8 (s->owner, addend);
break;
case 16:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 2);
if (suc && rel->howto->pc_relative)
_addend = bfd_get_signed_16 (s->owner, addend);
else if (suc)
_addend = bfd_get_16 (s->owner, addend);
break;
case 32:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 4);
if (suc && rel->howto->pc_relative)
_addend = bfd_get_signed_32 (s->owner, addend);
else if (suc)
_addend = bfd_get_32 (s->owner, addend);
break;
case 64:
suc = bfd_get_section_contents (s->owner, s, addend, rel->address, 8);
if (suc)
_addend = bfd_get_64 (s->owner, addend);
break;
}
if (! suc)
einfo (_("%C: Cannot get section contents - auto-import exception\n"),
@ -1122,11 +1122,13 @@ make_import_fixup (arelent *rel, asection *s)
if (pep_dll_extra_pe_debug)
{
printf ("import of 0x%lx(0x%lx) sec_addr=0x%lx", (long) _addend, (long) rel->addend, (long) rel->address);
if (rel->howto->pc_relative) printf (" pcrel");
printf (" %d bit rel.\n",(int) rel->howto->bitsize);
}
pep_create_import_fixup (rel, s, _addend);
printf ("import of 0x%lx(0x%lx) sec_addr=0x%lx",
(long) _addend, (long) rel->addend, (long) rel->address);
if (rel->howto->pc_relative)
printf (" pcrel");
printf (" %d bit rel.\n", (int) rel->howto->bitsize);
}
pep_create_import_fixup (rel, s, _addend, name);
return 1;
}
@ -1135,32 +1137,46 @@ static void
pep_find_data_imports (void)
{
struct bfd_link_hash_entry *undef, *sym;
size_t namelen;
char *buf, *name;
if (link_info.pei386_auto_import == 0)
return;
for (undef = link_info.hash->undefs; undef; undef=undef->u.undef.next)
namelen = 0;
for (undef = link_info.hash->undefs; undef; undef = undef->u.undef.next)
{
if (undef->type == bfd_link_hash_undefined)
{
/* C++ symbols are *long*. */
#define BUF_SIZE 4096
char buf[BUF_SIZE];
size_t len = strlen (undef->root.string);
if (namelen < len)
namelen = len;
}
}
if (namelen == 0)
return;
/* We are being a bit cunning here. The buffer will have space for
prefixes at the beginning. The prefix is modified here and in a
number of functions called from this function. */
#define PREFIX_LEN 32
buf = xmalloc (PREFIX_LEN + namelen + 1);
name = buf + PREFIX_LEN;
for (undef = link_info.hash->undefs; undef; undef = undef->u.undef.next)
{
if (undef->type == bfd_link_hash_undefined)
{
char *impname;
if (pep_dll_extra_pe_debug)
printf ("%s:%s\n", __FUNCTION__, undef->root.string);
if (strlen (undef->root.string) > (BUF_SIZE - 6))
{
/* PR linker/18466. */
einfo (_("%P: internal error: symbol too long: %s\n"),
undef->root.string);
return;
}
strcpy (name, undef->root.string);
impname = name - (sizeof "__imp_" - 1);
memcpy (impname, "__imp_", sizeof "__imp_" - 1);
sprintf (buf, "__imp_%s", undef->root.string);
sym = bfd_link_hash_lookup (link_info.hash, buf, 0, 0, 1);
sym = bfd_link_hash_lookup (link_info.hash, impname, 0, 0, 1);
if (sym && sym->type == bfd_link_hash_defined)
{
@ -1185,13 +1201,12 @@ pep_find_data_imports (void)
if (pep_dll_extra_pe_debug)
printf ("->%s\n", symbols[i]->name);
pep_data_import_dll = (char*) (symbols[i]->name +
U_SIZE ("_head_") - 1);
pep_data_import_dll = (char *) (symbols[i]->name
+ U_SIZE ("_head_") - 1);
break;
}
pep_walk_relocs_of_symbol (&link_info, undef->root.string,
make_import_fixup);
pep_walk_relocs_of_symbol (&link_info, name, make_import_fixup);
/* Let's differentiate it somehow from defined. */
undef->type = bfd_link_hash_defweak;
@ -1204,6 +1219,7 @@ pep_find_data_imports (void)
}
}
}
free (buf);
}
static bfd_boolean

58
ld/pe-dll.c
View File

@ -1275,8 +1275,8 @@ static struct bfd_section *current_sec;
void
pe_walk_relocs_of_symbol (struct bfd_link_info *info,
const char *name,
int (*cb) (arelent *, asection *))
char *name,
int (*cb) (arelent *, asection *, char *))
{
bfd *b;
asection *s;
@ -1315,7 +1315,7 @@ pe_walk_relocs_of_symbol (struct bfd_link_info *info,
struct bfd_symbol *sym = *relocs[i]->sym_ptr_ptr;
if (!strcmp (name, sym->name))
cb (relocs[i], s);
cb (relocs[i], s, name);
}
free (relocs);
@ -2396,37 +2396,21 @@ make_singleton_name_thunk (const char *import, bfd *parent)
}
static char *
make_import_fixup_mark (arelent *rel)
make_import_fixup_mark (arelent *rel, char *name)
{
/* We convert reloc to symbol, for later reference. */
static int counter;
static char *fixup_name = NULL;
static size_t buffer_len = 0;
static unsigned int counter;
struct bfd_symbol *sym = *rel->sym_ptr_ptr;
bfd *abfd = bfd_asymbol_bfd (sym);
struct bfd_link_hash_entry *bh;
char *fixup_name, buf[26];
size_t prefix_len;
if (!fixup_name)
{
fixup_name = xmalloc (384);
buffer_len = 384;
}
if (strlen (sym->name) + 25 > buffer_len)
/* Assume 25 chars for "__fu" + counter + "_". If counter is
bigger than 20 digits long, we've got worse problems than
overflowing this buffer... */
{
free (fixup_name);
/* New buffer size is length of symbol, plus 25, but
then rounded up to the nearest multiple of 128. */
buffer_len = ((strlen (sym->name) + 25) + 127) & ~127;
fixup_name = xmalloc (buffer_len);
}
sprintf (fixup_name, "__fu%d_%s", counter++, sym->name);
/* "name" buffer has space before the symbol name for prefixes. */
sprintf (buf, "__fu%d_", counter++);
prefix_len = strlen (buf);
fixup_name = name - prefix_len;
memcpy (fixup_name, buf, prefix_len);
bh = NULL;
bfd_coff_link_add_one_symbol (&link_info, abfd, fixup_name, BSF_GLOBAL,
@ -2626,23 +2610,25 @@ pe_create_runtime_relocator_reference (bfd *parent)
}
void
pe_create_import_fixup (arelent *rel, asection *s, bfd_vma addend)
pe_create_import_fixup (arelent *rel, asection *s, bfd_vma addend, char *name)
{
char buf[300];
struct bfd_symbol *sym = *rel->sym_ptr_ptr;
struct bfd_link_hash_entry *name_thunk_sym;
struct bfd_link_hash_entry *name_imp_sym;
const char *name = sym->name;
char *fixup_name = make_import_fixup_mark (rel);
char *fixup_name, *impname;
bfd *b;
int need_import_table = 1;
sprintf (buf, "__imp_%s", name);
name_imp_sym = bfd_link_hash_lookup (link_info.hash, buf, 0, 0, 1);
/* name buffer is allocated with space at beginning for prefixes. */
impname = name - (sizeof "__imp_" - 1);
memcpy (impname, "__imp_", sizeof "__imp_" - 1);
name_imp_sym = bfd_link_hash_lookup (link_info.hash, impname, 0, 0, 1);
sprintf (buf, "__nm_thnk_%s", name);
impname = name - (sizeof "__nm_thnk_" - 1);
memcpy (impname, "__nm_thnk_", sizeof "__nm_thnk_" - 1);
name_thunk_sym = bfd_link_hash_lookup (link_info.hash, impname, 0, 0, 1);
name_thunk_sym = bfd_link_hash_lookup (link_info.hash, buf, 0, 0, 1);
fixup_name = make_import_fixup_mark (rel, name);
/* For version 2 pseudo relocation we don't need to add an import
if the import symbol is already present. */

4
ld/pe-dll.h
View File

@ -62,9 +62,9 @@ extern void pe_dll_fill_sections
extern void pe_exe_fill_sections
(bfd *, struct bfd_link_info *);
extern void pe_walk_relocs_of_symbol
(struct bfd_link_info *, const char *, int (*) (arelent *, asection *));
(struct bfd_link_info *, char *, int (*) (arelent *, asection *, char *));
extern void pe_create_import_fixup
(arelent * rel, asection *, bfd_vma);
(arelent * rel, asection *, bfd_vma, char *);
extern bfd_boolean pe_bfd_is_dll
(bfd *);
extern void pe_output_file_set_long_section_names

5
ld/pep-dll.h
View File

@ -53,8 +53,9 @@ extern void pep_exe_build_sections (bfd *, struct bfd_link_info *);
extern void pep_dll_fill_sections (bfd *, struct bfd_link_info *);
extern void pep_exe_fill_sections (bfd *, struct bfd_link_info *);
extern void pep_walk_relocs_of_symbol
(struct bfd_link_info *, const char *, int (*) (arelent *, asection *));
extern void pep_create_import_fixup (arelent * rel, asection *, bfd_vma);
(struct bfd_link_info *, char *, int (*) (arelent *, asection *, char *));
extern void pep_create_import_fixup (arelent * rel, asection *, bfd_vma,
char *);
extern bfd_boolean pep_bfd_is_dll (bfd *);
extern void pep_output_file_set_long_section_names (bfd *);