Bug#890359: binutils: Fix GOT relocation overflow on SPARC
Source: binutils
Version: 2.30-4
Severity: normal
Tags: patch upstream
User: debian-sparc@lists.debian.org
Usertags: sparc64
Hi!
binutils upstream contains another fix for sparc64 which we
need to address some memory corruption issues for the generated
binaries.
In particular, the fix is necessary to further unbreak the rust
compiler on sparc64, with one other fix necessary to completely
fix rustc on sparc64.
Since this particular bug causes the generated binaries to be
corrupted, it's rather important to have this patch soonish.
Thanks,
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
Description: Fix GOT relocation overflow on SPARC.
There are 2 failures left in the linker testsuite on SPARC64/Linux and
they are caused by 2 different issues leading to the same end effect:
the overflow of the relocation section for the GOT, i.e. the linker
generates too many dynamic relocations for the GOT wrt the size of the
relocation section, leading to memory corruption and missing relocations
in the final binary.
.
The first issue was introduced by:
https://sourceware.org/ml/binutils/2017-06/msg00368.html
which makes the linker generate more R_SPARC_RELATIVE relocations for
the GOT without adjusting the size of the relocation section. This is
fixed by (1) preventively adjusting this size in allocate_dynrelocs and
(2) generating R_SPARC_NONE if needed when R_SPARC_GOTDATA_OP is relaxed.
.
The second issue is that we generate a GOT relocation for an undefined
weak symbol with non-default visibility in a PIC binary without accounting
for that in the size of the relocation section. Since the address of the
symbol should resolve to 0 at run time, it is fixed by not generating the
relocation at all, i.e. leaving the GOT entry zeroed.
.
Author: Eric Botcazou <ebotcazou@gcc.gnu.org>
Last-Update: 2018-02-11
--- binutils-2.30.orig/bfd/elfxx-sparc.c
+++ binutils-2.30/bfd/elfxx-sparc.c
@@ -673,9 +673,9 @@ _bfd_sparc_elf_info_to_howto (bfd *abfd
((EH)->elf.root.type == bfd_link_hash_undefweak \
&& bfd_link_executable (INFO) \
&& (_bfd_sparc_elf_hash_table (INFO)->interp == NULL \
- || !(EH)->has_got_reloc \
+ || !(INFO)->dynamic_undefined_weak \
|| (EH)->has_non_got_reloc \
- || !(INFO)->dynamic_undefined_weak))
+ || !(EH)->has_got_reloc))
/* SPARC ELF linker hash entry. */
@@ -750,6 +750,7 @@ sparc_elf_append_rela (bfd *abfd, asecti
bfd_byte *loc;
bed = get_elf_backend_data (abfd);
+ BFD_ASSERT (s->reloc_count * bed->s->sizeof_rela < s->size);
loc = s->contents + (s->reloc_count++ * bed->s->sizeof_rela);
bed->s->swap_reloca_out (abfd, rel, loc);
}
@@ -1310,8 +1311,7 @@ _bfd_sparc_elf_copy_indirect_symbol (str
eind->dyn_relocs = NULL;
}
- if (ind->root.type == bfd_link_hash_indirect
- && dir->got.refcount <= 0)
+ if (ind->root.type == bfd_link_hash_indirect && dir->got.refcount <= 0)
{
edir->tls_type = eind->tls_type;
eind->tls_type = GOT_UNKNOWN;
@@ -2004,8 +2004,8 @@ _bfd_sparc_elf_adjust_dynamic_symbol (st
if (h->plt.refcount <= 0
|| (h->type != STT_GNU_IFUNC
&& (SYMBOL_CALLS_LOCAL (info, h)
- || (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
- && h->root.type == bfd_link_hash_undefweak))))
+ || (h->root.type == bfd_link_hash_undefweak
+ && ELF_ST_VISIBILITY (h->other) != STV_DEFAULT))))
{
/* This case can occur if we saw a WPLT30 reloc in an input
file, but the symbol was never referred to by a dynamic
@@ -2124,12 +2124,11 @@ allocate_dynrelocs (struct elf_link_hash
&& h->def_regular
&& h->ref_regular))
{
- /* Make sure this symbol is output as a dynamic symbol.
- Undefined weak syms won't yet be marked as dynamic. */
- if (h->dynindx == -1
- && !h->forced_local
+ /* Undefined weak syms won't yet be marked as dynamic. */
+ if (h->root.type == bfd_link_hash_undefweak
&& !resolved_to_zero
- && h->root.type == bfd_link_hash_undefweak)
+ && h->dynindx == -1
+ && !h->forced_local)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -2237,12 +2236,11 @@ allocate_dynrelocs (struct elf_link_hash
bfd_boolean dyn;
int tls_type = _bfd_sparc_elf_hash_entry(h)->tls_type;
- /* Make sure this symbol is output as a dynamic symbol.
- Undefined weak syms won't yet be marked as dynamic. */
- if (h->dynindx == -1
- && !h->forced_local
+ /* Undefined weak syms won't yet be marked as dynamic. */
+ if (h->root.type == bfd_link_hash_undefweak
&& !resolved_to_zero
- && h->root.type == bfd_link_hash_undefweak)
+ && h->dynindx == -1
+ && !h->forced_local)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -2256,21 +2254,25 @@ allocate_dynrelocs (struct elf_link_hash
s->size += SPARC_ELF_WORD_BYTES (htab);
dyn = htab->elf.dynamic_sections_created;
/* R_SPARC_TLS_IE_{HI22,LO10} needs one dynamic relocation,
- R_SPARC_TLS_GD_{HI22,LO10} needs one if local symbol and two if
- global. No dynamic relocations are needed against resolved
- undefined weak symbols in an executable. */
+ R_SPARC_TLS_GD_{HI22,LO10} needs one if local and two if global. */
if ((tls_type == GOT_TLS_GD && h->dynindx == -1)
|| tls_type == GOT_TLS_IE
|| h->type == STT_GNU_IFUNC)
htab->elf.srelgot->size += SPARC_ELF_RELA_BYTES (htab);
else if (tls_type == GOT_TLS_GD)
htab->elf.srelgot->size += 2 * SPARC_ELF_RELA_BYTES (htab);
- else if (((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
- && !resolved_to_zero)
- || h->root.type != bfd_link_hash_undefweak)
- && WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn,
- bfd_link_pic (info),
- h))
+ else if ((WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, bfd_link_pic (info), h)
+ /* Even if the symbol isn't dynamic, we may generate a
+ reloc for the dynamic linker in PIC mode. */
+ || (h->dynindx == -1
+ && !h->forced_local
+ && h->root.type != bfd_link_hash_undefweak
+ && bfd_link_pic (info)))
+ /* No dynamic relocations are needed against resolved
+ undefined weak symbols in an executable. */
+ && !(h->root.type == bfd_link_hash_undefweak
+ && (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
+ || resolved_to_zero)))
htab->elf.srelgot->size += SPARC_ELF_RELA_BYTES (htab);
}
else
@@ -2380,12 +2382,11 @@ allocate_dynrelocs (struct elf_link_hash
&& (h->root.type == bfd_link_hash_undefweak
|| h->root.type == bfd_link_hash_undefined))))
{
- /* Make sure this symbol is output as a dynamic symbol.
- Undefined weak syms won't yet be marked as dynamic. */
- if (h->dynindx == -1
- && !h->forced_local
+ /* Undefined weak syms won't yet be marked as dynamic. */
+ if (h->root.type == bfd_link_hash_undefweak
&& !resolved_to_zero
- && h->root.type == bfd_link_hash_undefweak)
+ && h->dynindx == -1
+ && !h->forced_local)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
@@ -3155,6 +3156,26 @@ _bfd_sparc_elf_relocate_section (bfd *ou
/* {ld,ldx} [%rs1 + %rs2], %rd --> add %rs1, %rs2, %rd */
relocation = 0x80000000 | (insn & 0x3e07c01f);
bfd_put_32 (output_bfd, relocation, contents + rel->r_offset);
+
+ /* If the symbol is global but not dynamic, an .rela.* slot has
+ been allocated for it in the GOT so output R_SPARC_NONE here.
+ See also the handling of other GOT relocations just below. */
+ if (h != NULL
+ && h->dynindx == -1
+ && !h->forced_local
+ && h->root.type != bfd_link_hash_undefweak
+ && (h->got.offset & 1) == 0
+ && bfd_link_pic (info))
+ {
+ asection *s = htab->elf.srelgot;
+ Elf_Internal_Rela outrel;
+
+ BFD_ASSERT (s != NULL);
+
+ memset (&outrel, 0, sizeof outrel);
+ sparc_elf_append_rela (output_bfd, s, &outrel);
+ h->got.offset |= 1;
+ }
}
continue;
}
@@ -3207,15 +3228,13 @@ _bfd_sparc_elf_relocate_section (bfd *ou
off &= ~1;
else
{
+ /* If this symbol isn't dynamic in PIC mode, treat it
+ like a local symbol in PIC mode below. */
if (h->dynindx == -1
&& !h->forced_local
&& h->root.type != bfd_link_hash_undefweak
&& bfd_link_pic (info))
- {
- /* If this symbol isn't dynamic in PIC
- generate R_SPARC_RELATIVE here. */
- relative_reloc = TRUE;
- }
+ relative_reloc = TRUE;
else
SPARC_ELF_PUT_WORD (htab, output_bfd, relocation,
htab->elf.sgot->contents + off);
@@ -3239,6 +3258,8 @@ _bfd_sparc_elf_relocate_section (bfd *ou
off &= ~1;
else
{
+ /* For a local symbol in PIC mode, we need to generate a
+ R_SPARC_RELATIVE reloc for the dynamic linker. */
if (bfd_link_pic (info))
relative_reloc = TRUE;
else
@@ -3250,12 +3271,9 @@ _bfd_sparc_elf_relocate_section (bfd *ou
if (relative_reloc)
{
- asection *s;
+ asection *s = htab->elf.srelgot;
Elf_Internal_Rela outrel;
- /* We need to generate a R_SPARC_RELATIVE reloc
- for the dynamic linker. */
- s = htab->elf.srelgot;
BFD_ASSERT (s != NULL);
outrel.r_offset = (htab->elf.sgot->output_section->vma
@@ -3387,9 +3405,9 @@ _bfd_sparc_elf_relocate_section (bfd *ou
in PIE. */
if ((bfd_link_pic (info)
&& (h == NULL
- || ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
- && !resolved_to_zero)
- || h->root.type != bfd_link_hash_undefweak))
+ || !(h->root.type == bfd_link_hash_undefweak
+ && (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
+ || resolved_to_zero)))
&& (! howto->pc_relative
|| !SYMBOL_CALLS_LOCAL (info, h)))
|| (!bfd_link_pic (info)
@@ -3476,7 +3494,6 @@ _bfd_sparc_elf_relocate_section (bfd *ou
|| !SYMBOLIC_BIND (info, h)
|| !h->def_regular))
{
- BFD_ASSERT (h->dynindx != -1);
outrel.r_info = SPARC_ELF_R_INFO (htab, rel, h->dynindx, r_type);
outrel.r_addend = rel->r_addend;
}
@@ -4321,7 +4338,7 @@ _bfd_sparc_elf_finish_dynamic_symbol (bf
struct _bfd_sparc_elf_link_hash_table *htab;
const struct elf_backend_data *bed;
struct _bfd_sparc_elf_link_hash_entry *eh;
- bfd_boolean local_undefweak;
+ bfd_boolean resolved_to_zero;
htab = _bfd_sparc_elf_hash_table (info);
BFD_ASSERT (htab != NULL);
@@ -4332,7 +4349,7 @@ _bfd_sparc_elf_finish_dynamic_symbol (bf
/* We keep PLT/GOT entries without dynamic PLT/GOT relocations for
resolved undefined weak symbols in executable so that their
references have value 0 at run-time. */
- local_undefweak = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
+ resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
if (h->plt.offset != (bfd_vma) -1)
{
@@ -4457,8 +4474,7 @@ _bfd_sparc_elf_finish_dynamic_symbol (bf
loc += rela_index * bed->s->sizeof_rela;
bed->s->swap_reloca_out (output_bfd, &rela, loc);
- if (!local_undefweak
- && !h->def_regular)
+ if (!resolved_to_zero && !h->def_regular)
{
/* Mark the symbol as undefined, rather than as defined in
the .plt section. Leave the value alone. */
@@ -4472,12 +4488,14 @@ _bfd_sparc_elf_finish_dynamic_symbol (bf
}
}
- /* Don't generate dynamic GOT relocation against undefined weak
- symbol in executable. */
+ /* Don't generate dynamic GOT relocation against resolved undefined weak
+ symbols in an executable. */
if (h->got.offset != (bfd_vma) -1
&& _bfd_sparc_elf_hash_entry(h)->tls_type != GOT_TLS_GD
&& _bfd_sparc_elf_hash_entry(h)->tls_type != GOT_TLS_IE
- && !local_undefweak)
+ && !(h->root.type == bfd_link_hash_undefweak
+ && (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
+ || resolved_to_zero)))
{
asection *sgot;
asection *srela;
@@ -4513,8 +4531,8 @@ _bfd_sparc_elf_finish_dynamic_symbol (bf
+ (h->got.offset & ~(bfd_vma) 1));
return TRUE;
}
- else if (bfd_link_pic (info)
- && SYMBOL_REFERENCES_LOCAL (info, h))
+
+ if (bfd_link_pic (info) && SYMBOL_REFERENCES_LOCAL (info, h))
{
asection *sec = h->root.u.def.section;
if (h->type == STT_GNU_IFUNC)
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