[PATCH] elf: Discard input .note.gnu.build-id sections


Valery Chernous
 

From: Valerii Chernous <vchernou@...>

Originally issue:
building of glibc 2.32 or 2.34 with option "-Wl,--build-id"
produce libc.so.6 with section ".note.gnu.build-id" that have
invalid(double, 0x48) section size. It happens because glibc
use sublibraries for linking libc.so.6
ld produce this sublibraries with build-id section and on last
linking stage loads this sections as input for linking.
ld should create new(valid) ".note.gnu.build-id" into function
ldelf_setup_build_id on last linking stage but it skip creating because
build-id section already exists.
As result libc.so.6 contain ".note.gnu.build-id" with build-ids from
sublibraries and without valid build-id

Howto solved:
1. Discard input .note.gnu.build-id sections.
2. Clear the build ID field before writing.
3. Use bfd_make_section_anyway_with_flags to create the output
.note.gnu.build-id section.

Upstream-Status: Backport

Reference to upstream patch:
[https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=1f1d0f8888a6c944e612b416a2a6e11abcf5199f]

Signed-off-by: Valerii Chernous <vchernou@...>
Signed-off-by: Valery Chernous <valery.chernous@...>
---
.../binutils/binutils-2.37.inc | 1 +
...rd-input-.note.gnu.build-id-sections.patch | 215 ++++++++++++++++++
2 files changed, 216 insertions(+)
create mode 100644 meta/recipes-devtools/binutils/binutils/0001-elf-Discard-input-.note.gnu.build-id-sections.patch

diff --git a/meta/recipes-devtools/binutils/binutils-2.37.inc b/meta/recipes-devtools/binutils/binutils-2.37.inc
index 8f91c6460d..c565adc4b7 100644
--- a/meta/recipes-devtools/binutils/binutils-2.37.inc
+++ b/meta/recipes-devtools/binutils/binutils-2.37.inc
@@ -35,5 +35,6 @@ SRC_URI = "\
file://0015-sync-with-OE-libtool-changes.patch \
file://0016-Check-for-clang-before-checking-gcc-version.patch \
file://0017-bfd-Close-the-file-descriptor-if-there-is-no-archive.patch \
+ file://0001-elf-Discard-input-.note.gnu.build-id-sections.patch \
"
S = "${WORKDIR}/git"
diff --git a/meta/recipes-devtools/binutils/binutils/0001-elf-Discard-input-.note.gnu.build-id-sections.patch b/meta/recipes-devtools/binutils/binutils/0001-elf-Discard-input-.note.gnu.build-id-sections.patch
new file mode 100644
index 0000000000..c93af4e46f
--- /dev/null
+++ b/meta/recipes-devtools/binutils/binutils/0001-elf-Discard-input-.note.gnu.build-id-sections.patch
@@ -0,0 +1,215 @@
+From b2e18d3ea300f7491705b6e86a7cc3d6366e3b1f Mon Sep 17 00:00:00 2001
+From: "H.J. Lu" <hjl.tools@...>
+Date: Tue, 30 Nov 2021 20:40:38 -0800
+Subject: [PATCH] elf: Discard input .note.gnu.build-id sections
+
+1. Discard input .note.gnu.build-id sections.
+2. Clear the build ID field before writing.
+3. Use bfd_make_section_anyway_with_flags to create the output
+.note.gnu.build-id section.
+
+ PR ld/28639
+ * ldelf.c (ldelf_after_open): Discard input .note.gnu.build-id
+ sections, excluding the first one.
+ (write_build_id): Clear the build ID field before writing.
+ (ldelf_setup_build_id): Use bfd_make_section_anyway_with_flags
+ to create the output .note.gnu.build-id section.
+ * testsuite/ld-elf/build-id.exp: New file.
+ * testsuite/ld-elf/pr28639a.rd: Likewise.
+ * testsuite/ld-elf/pr28639b.rd: Likewise.
+ * testsuite/ld-elf/pr28639c.rd: Likewise.
+ * testsuite/ld-elf/pr28639d.rd: Likewise.
+
+Upstream-Status: Backport
+
+Reference to upstream patch:
+[https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=1f1d0f8888a6c944e612b416a2a6e11abcf5199f]
+---
+ ld/ldelf.c | 15 ++++++-
+ ld/testsuite/ld-elf/build-id.exp | 77 ++++++++++++++++++++++++++++++++
+ ld/testsuite/ld-elf/pr28639a.rd | 6 +++
+ ld/testsuite/ld-elf/pr28639b.rd | 6 +++
+ ld/testsuite/ld-elf/pr28639c.rd | 10 +++++
+ ld/testsuite/ld-elf/pr28639d.rd | 4 ++
+ 6 files changed, 117 insertions(+), 1 deletion(-)
+ create mode 100644 ld/testsuite/ld-elf/build-id.exp
+ create mode 100644 ld/testsuite/ld-elf/pr28639a.rd
+ create mode 100644 ld/testsuite/ld-elf/pr28639b.rd
+ create mode 100644 ld/testsuite/ld-elf/pr28639c.rd
+ create mode 100644 ld/testsuite/ld-elf/pr28639d.rd
+
+diff --git a/ld/ldelf.c b/ld/ldelf.c
+index 21e655bb55c..8501d98b48f 100644
+--- a/ld/ldelf.c
++++ b/ld/ldelf.c
+@@ -1043,6 +1043,15 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd,
+ /* Do not allow executable files to be used as inputs to the link. */
+ for (abfd = link_info.input_bfds; abfd; abfd = abfd->link.next)
+ {
++ /* Discard input .note.gnu.build-id sections. */
++ s = bfd_get_section_by_name (abfd, ".note.gnu.build-id");
++ while (s != NULL)
++ {
++ if (s != elf_tdata (link_info.output_bfd)->o->build_id.sec)
++ s->flags |= SEC_EXCLUDE;
++ s = bfd_get_next_section_by_name (NULL, s);
++ }
++
+ if (abfd->xvec->flavour == bfd_target_elf_flavour
+ && !bfd_input_just_syms (abfd)
+ && elf_tdata (abfd) != NULL
+@@ -1387,6 +1396,9 @@ write_build_id (bfd *abfd)
+ id_bits = contents + size;
+ size = asec->size - size;
+
++ /* Clear the build ID field. */
++ memset (id_bits, 0, size);
++
+ bfd_h_put_32 (abfd, sizeof "GNU", &e_note->namesz);
+ bfd_h_put_32 (abfd, size, &e_note->descsz);
+ bfd_h_put_32 (abfd, NT_GNU_BUILD_ID, &e_note->type);
+@@ -1418,7 +1430,8 @@ ldelf_setup_build_id (bfd *ibfd)
+
+ flags = (SEC_ALLOC | SEC_LOAD | SEC_IN_MEMORY
+ | SEC_LINKER_CREATED | SEC_READONLY | SEC_DATA);
+- s = bfd_make_section_with_flags (ibfd, ".note.gnu.build-id", flags);
++ s = bfd_make_section_anyway_with_flags (ibfd, ".note.gnu.build-id",
++ flags);
+ if (s != NULL && bfd_set_section_alignment (s, 2))
+ {
+ struct elf_obj_tdata *t = elf_tdata (link_info.output_bfd);
+diff --git a/ld/testsuite/ld-elf/build-id.exp b/ld/testsuite/ld-elf/build-id.exp
+new file mode 100644
+index 00000000000..19c22a75c4d
+--- /dev/null
++++ b/ld/testsuite/ld-elf/build-id.exp
+@@ -0,0 +1,77 @@
++# Expect script for --build-id tests.
++# Copyright (C) 2021 Free Software Foundation, Inc.
++#
++# This file is part of the 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.
++#
++
++# Exclude non-ELF targets.
++
++if ![is_elf_format] {
++ return
++}
++
++if { [istarget frv-*-*] || [istarget lm32-*-*] } {
++ return
++}
++
++if { !([istarget *-*-linux*]
++ || [istarget arm*-*-uclinuxfdpiceabi]
++ || [istarget *-*-nacl*]
++ || [istarget *-*-gnu*]) } then {
++ return
++}
++
++run_ld_link_tests [list \
++ [list \
++ "pr28639a.o" \
++ "-r --build-id=md5" \
++ "" \
++ "" \
++ {start.s} \
++ {{readelf {--notes} pr28639a.rd}} \
++ "pr28639a.o" \
++ ] \
++ [list \
++ "pr28639a.o" \
++ "-r --build-id" \
++ "" \
++ "" \
++ {dummy.s} \
++ {{readelf {--notes} pr28639b.rd}} \
++ "pr28639b.o" \
++ ] \
++ [list \
++ "pr28639a" \
++ "--build-id tmpdir/pr28639a.o tmpdir/pr28639b.o" \
++ "" \
++ "" \
++ {dummy.s} \
++ {{readelf {--notes} pr28639b.rd} \
++ {readelf {--notes} pr28639c.rd}} \
++ "pr28639a" \
++ ] \
++ [list \
++ "pr28639b" \
++ "--build-id=none tmpdir/pr28639a.o tmpdir/pr28639b.o" \
++ "" \
++ "" \
++ {dummy.s} \
++ {{readelf {--notes} pr28639d.rd}} \
++ "pr28639b" \
++ ] \
++]
+diff --git a/ld/testsuite/ld-elf/pr28639a.rd b/ld/testsuite/ld-elf/pr28639a.rd
+new file mode 100644
+index 00000000000..e85087064d0
+--- /dev/null
++++ b/ld/testsuite/ld-elf/pr28639a.rd
+@@ -0,0 +1,6 @@
++#...
++Displaying notes found in: \.note\.gnu\.build-id
++ Owner Data size Description
++ GNU 0x00000010 NT_GNU_BUILD_ID \(unique build ID bitstring\)
++ Build ID: [0-9a-f]+
++#pass
+diff --git a/ld/testsuite/ld-elf/pr28639b.rd b/ld/testsuite/ld-elf/pr28639b.rd
+new file mode 100644
+index 00000000000..04dcb04bec2
+--- /dev/null
++++ b/ld/testsuite/ld-elf/pr28639b.rd
+@@ -0,0 +1,6 @@
++#...
++Displaying notes found in: \.note\.gnu\.build-id
++ Owner Data size Description
++ GNU 0x00000014 NT_GNU_BUILD_ID \(unique build ID bitstring\)
++ Build ID: [0-9a-f]+
++#pass
+diff --git a/ld/testsuite/ld-elf/pr28639c.rd b/ld/testsuite/ld-elf/pr28639c.rd
+new file mode 100644
+index 00000000000..64221e5fa51
+--- /dev/null
++++ b/ld/testsuite/ld-elf/pr28639c.rd
+@@ -0,0 +1,10 @@
++#failif
++#...
++Displaying notes found in: \.note\.gnu\.build-id
++ Owner Data size Description
++ GNU 0x[0-9a-f]+ NT_GNU_BUILD_ID \(unique build ID bitstring\)
++ Build ID: [0-9a-f]+
++ Owner Data size Description
++ GNU 0x[0-9a-f]+ NT_GNU_BUILD_ID \(unique build ID bitstring\)
++ Build ID: [0-9a-f]+
++#...
+diff --git a/ld/testsuite/ld-elf/pr28639d.rd b/ld/testsuite/ld-elf/pr28639d.rd
+new file mode 100644
+index 00000000000..897c8493efa
+--- /dev/null
++++ b/ld/testsuite/ld-elf/pr28639d.rd
+@@ -0,0 +1,4 @@
++#failif
++#...
++Displaying notes found in: \.note\.gnu\.build-id
++#...
+--
+
--
2.25.1

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