From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa1-x2f.google.com (mail-oa1-x2f.google.com [IPv6:2001:4860:4864:20::2f]) by sourceware.org (Postfix) with ESMTPS id 85E4B3857BAB for ; Tue, 24 May 2022 21:15:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 85E4B3857BAB Received: by mail-oa1-x2f.google.com with SMTP id 586e51a60fabf-f17f1acffeso23816729fac.4 for ; Tue, 24 May 2022 14:15:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=c3GWudTE2bYue3ohL88QakXATw9o/KdLhPYwpM25tH8=; b=oqlQwZHKdDaHN111g5epGNPSNzU947Y45uqiAqSltlIjC7PfyDIAzKxbIfUry/Wv8e O7VMx17InOWXrwG2ElmYAR1pI925azH9ZDxNm59IpGdjauKnQiSA0VnJpL3kZGhhjfEw /PyzH8YMBat9psAK9JsalbKFq5FtSXqGKuzCNHU7gj+WUTX0aGbMIHyYQWsXtXb+CpF7 jOTBJQraZEvJEVKhhJaYxSuPc7AlrYPImA6DlrUSjdDtoQGvVTQMQwZ7u5q/grh/A9hO 1hWHS2qd8125Q7aEumeudC24hEPBaR9zriAcyPcSUYbjSacifgQtkA0Yun2CI4BZP6pM Um9A== X-Gm-Message-State: AOAM531r5O6wP770eIP6C3ecR8SRyfQIg6bJfTKQOkl0rdFwpRNiMuen eb6FGiMQ+FewX4AWL/Adsnb5ti5HKxi8nQ== X-Google-Smtp-Source: ABdhPJyh7lOUXy9scotzazjrRvHv04OK2zRd7JRMWKSu1lbsAqG7M7R6YWKJ+naZ+NrpuIT8NFBs4g== X-Received: by 2002:a05:6870:8314:b0:ee:72a1:ce63 with SMTP id p20-20020a056870831400b000ee72a1ce63mr3810953oae.285.1653426912848; Tue, 24 May 2022 14:15:12 -0700 (PDT) Received: from localhost ([2a01:4b00:f41a:3600:df86:cebc:8870:2184]) by smtp.gmail.com with ESMTPSA id 66-20020a9d0f48000000b00605fd407259sm5450657ott.3.2022.05.24.14.15.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 May 2022 14:15:12 -0700 (PDT) From: luca.boccassi@gmail.com To: binutils@sourceware.org Subject: [PATCH v2] ld: add --package-metadata Date: Tue, 24 May 2022 22:15:07 +0100 Message-Id: <20220524211507.177629-1-luca.boccassi@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220515191846.114257-1-luca.boccassi@gmail.com> References: <20220515191846.114257-1-luca.boccassi@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: binutils@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Binutils mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 May 2022 21:15:20 -0000 From: Luca Boccassi Generate a .note.package FDO package metadata ELF note, following the spec: https://systemd.io/ELF_PACKAGE_METADATA/ If the jansson library is available at build time (and not explicitly disabled), link ld to it, and use it to validate that the input is correct JSON, to avoid writing garbage to the file. If no configure option is passed and jansson (or pkg-config) is not found, then it is just skipped (with a non-fatal warning). The configure option --enable-jansson can be used to explicitly enable it (error out when not found) or to explicitly disable it (don't even look for it). This allows bootstrappers (or others who are not interested) to seamlessly skip it without issues." --- v2: fix style issues fix ASAN issue: note storage is rounded up, but that size was used to read the json input, which is fixed add entry to NEWS add note about json validation to docs bfd/elf-bfd.h | 8 ++ bfd/elf.c | 8 +- ld/Makefile.am | 6 +- ld/NEWS | 6 ++ ld/configure.ac | 35 +++++++ ld/emultempl/elf.em | 9 ++ ld/ld.texi | 12 +++ ld/ldelf.c | 136 ++++++++++++++++++++++++++- ld/ldelf.h | 2 + ld/lexsup.c | 2 + ld/testsuite/ld-elf/package-note.exp | 45 +++++++++ ld/testsuite/ld-elf/package-note.rd | 6 ++ 12 files changed, 268 insertions(+), 7 deletions(-) create mode 100644 ld/testsuite/ld-elf/package-note.exp create mode 100644 ld/testsuite/ld-elf/package-note.rd diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h index c7c0a793b15..65bd1128263 100644 --- a/bfd/elf-bfd.h +++ b/bfd/elf-bfd.h @@ -1918,6 +1918,14 @@ struct output_elf_obj_tdata asection *sec; } build_id; + /* FDO_PACKAGING_METADATA note type info. */ + struct + { + bool (*after_write_object_contents) (bfd *); + const char *json; + asection *sec; + } package_metadata; + /* Records the result of `get_program_header_size'. */ bfd_size_type program_header_size; diff --git a/bfd/elf.c b/bfd/elf.c index c493aa5b172..fcc7d14a1d6 100644 --- a/bfd/elf.c +++ b/bfd/elf.c @@ -6779,8 +6779,12 @@ _bfd_elf_write_object_contents (bfd *abfd) return false; /* This is last since write_shdrs_and_ehdr can touch i_shdrp[0]. */ - if (t->o->build_id.after_write_object_contents != NULL) - return (*t->o->build_id.after_write_object_contents) (abfd); + if (t->o->build_id.after_write_object_contents != NULL + && !(*t->o->build_id.after_write_object_contents) (abfd)) + return false; + if (t->o->package_metadata.after_write_object_contents != NULL + && !(*t->o->package_metadata.after_write_object_contents) (abfd)) + return false; return true; } diff --git a/ld/Makefile.am b/ld/Makefile.am index e53bef13bb8..a3cd7891840 100644 --- a/ld/Makefile.am +++ b/ld/Makefile.am @@ -45,7 +45,7 @@ ELF_CLFAGS=-DELF_LIST_OPTIONS=@elf_list_options@ \ -DELF_PLT_UNWIND_LIST_OPTIONS=@elf_plt_unwind_list_options@ WARN_CFLAGS = @WARN_CFLAGS@ NO_WERROR = @NO_WERROR@ -AM_CFLAGS = $(WARN_CFLAGS) $(ELF_CLFAGS) +AM_CFLAGS = $(WARN_CFLAGS) $(ELF_CLFAGS) $(JANSSON_CFLAGS) # We put the scripts in the directory $(scriptdir)/ldscripts. # We can't put the scripts in $(datadir) because the SEARCH_DIR @@ -964,8 +964,8 @@ ld_new_SOURCES = ldgram.y ldlex-wrapper.c lexsup.c ldlang.c mri.c ldctor.c ldmai ldwrite.c ldexp.c ldemul.c ldver.c ldmisc.c ldfile.c ldcref.c plugin.c \ ldbuildid.c ld_new_DEPENDENCIES = $(EMULATION_OFILES) $(EMUL_EXTRA_OFILES) \ - $(BFDLIB) $(LIBCTF) $(LIBIBERTY) $(LIBINTL_DEP) -ld_new_LDADD = $(EMULATION_OFILES) $(EMUL_EXTRA_OFILES) $(BFDLIB) $(LIBCTF) $(LIBIBERTY) $(LIBINTL) $(ZLIB) + $(BFDLIB) $(LIBCTF) $(LIBIBERTY) $(LIBINTL_DEP) $(JANSSON_LIBS) +ld_new_LDADD = $(EMULATION_OFILES) $(EMUL_EXTRA_OFILES) $(BFDLIB) $(LIBCTF) $(LIBIBERTY) $(LIBINTL) $(ZLIB) $(JANSSON_LIBS) # Dependency tracking for the generated emulation files. EXTRA_ld_new_SOURCES += $(ALL_EMULATION_SOURCES) $(ALL_64_EMULATION_SOURCES) diff --git a/ld/NEWS b/ld/NEWS index 514d1d9f207..d2ade345b5d 100644 --- a/ld/NEWS +++ b/ld/NEWS @@ -36,6 +36,12 @@ * Remove (rudimentary) support for the x86-64 sub-architectures Intel L1OM and Intel K1OM. +* The ELF linker now supports a new --package-metadata option that allows + embedding a JSON payload in accordance to the Package Metadata specification. + If libjansson is present at build time, the linker will use it to validate + the input. This can be disabled with --disable-jansson. + For more details, see: https://systemd.io/ELF_PACKAGE_METADATA/ + Changes in 2.38: * Add -z pack-relative-relocs/-z no pack-relative-relocs to x86 ELF diff --git a/ld/configure.ac b/ld/configure.ac index 01121480c6d..a5e7afa89e8 100644 --- a/ld/configure.ac +++ b/ld/configure.ac @@ -289,6 +289,41 @@ fi AM_CONDITIONAL(ENABLE_LIBCTF, test "${enable_libctf}" = yes) AC_SUBST(enable_libctf) +# If pkg-config and libjansson are available, use them, skip if not. +# Allow explicitly enabling (error if not found)/disabling (skip even if found). +AC_ARG_ENABLE([jansson], + [AS_HELP_STRING([--enable-jansson], + [enable jansson [default=auto]])], + [enable_jansson=$enableval], + [enable_jansson="auto"]) + +if test "x$enable_jansson" != "xno"; then + PKG_PROG_PKG_CONFIG + AS_IF([test -n "$PKG_CONFIG"], + [ + PKG_CHECK_MODULES(JANSSON, [jansson], + [ + AC_DEFINE(HAVE_JANSSON, 1, [The jansson library is to be used]) + AC_SUBST([JANSSON_CFLAGS]) + AC_SUBST([JANSSON_LIBS]) + ], + [ + if test "x$enable_jansson" = "xyes"; then + AC_MSG_ERROR([Cannot find jansson library]) + else + AC_MSG_WARN([Cannot find jansson library]) + fi + ]) + ], + [ + if test "x$enable_jansson" = "xyes"; then + AC_MSG_ERROR([Cannot find pkg-config]) + else + AC_MSG_WARN([Cannot find pkg-config]) + fi + ]) +fi + AM_BINUTILS_WARNINGS AM_LC_MESSAGES diff --git a/ld/emultempl/elf.em b/ld/emultempl/elf.em index c027559908c..c52484f35d3 100644 --- a/ld/emultempl/elf.em +++ b/ld/emultempl/elf.em @@ -572,6 +572,7 @@ enum elf_options OPTION_EXCLUDE_LIBS, OPTION_HASH_STYLE, OPTION_BUILD_ID, + OPTION_PACKAGE_METADATA, OPTION_AUDIT, OPTION_COMPRESS_DEBUG }; @@ -602,6 +603,7 @@ EOF fi fragment < 0) + ldelf_emit_note_fdo_package_metadata = xstrdup (optarg); + break; + case OPTION_COMPRESS_DEBUG: if (strcasecmp (optarg, "none") == 0) link_info.compress_debug = COMPRESS_DEBUG_NONE; diff --git a/ld/ld.texi b/ld/ld.texi index a2b162ce5b5..eabbec8faa9 100644 --- a/ld/ld.texi +++ b/ld/ld.texi @@ -2935,6 +2935,18 @@ string identifying the original linked file does not change. Passing @code{none} for @var{style} disables the setting from any @code{--build-id} options earlier on the command line. + +@kindex --package-metadata=@var{JSON} +@item --package-metadata=@var{JSON} +Request the creation of a @code{.note.package} ELF note section. The +contents of the note are in JSON format, as per the package metadata +specification. For more information see: +https://systemd.io/ELF_PACKAGE_METADATA/ +If the JSON argument is missing/empty then this will disable the +creation of the metadata note, if one had been enabled by an earlier +occurrence of the --package-metdata option. +If the linker has been built with libjansson, then the JSON string +will be validated. @end table @c man end diff --git a/ld/ldelf.c b/ld/ldelf.c index 4094640b3f7..e5d1b32db06 100644 --- a/ld/ldelf.c +++ b/ld/ldelf.c @@ -39,6 +39,9 @@ #include #endif #include "ldelf.h" +#ifdef HAVE_JANSSON +#include +#endif struct dt_needed { @@ -49,6 +52,9 @@ struct dt_needed /* Style of .note.gnu.build-id section. */ const char *ldelf_emit_note_gnu_build_id; +/* Content of .note.package section. */ +const char *ldelf_emit_note_fdo_package_metadata; + /* These variables are required to pass information back and forth between after_open and check_needed and stat_needed and vercheck. */ @@ -1249,7 +1255,8 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd, } } - if (ldelf_emit_note_gnu_build_id != NULL) + if (ldelf_emit_note_gnu_build_id != NULL + || ldelf_emit_note_fdo_package_metadata != NULL) { /* Find an ELF input. */ for (abfd = link_info.input_bfds; @@ -1262,11 +1269,18 @@ ldelf_after_open (int use_libpath, int native, int is_linux, int is_freebsd, /* PR 10555: If there are no ELF input files do not try to create a .note.gnu-build-id section. */ if (abfd == NULL - || !ldelf_setup_build_id (abfd)) + || (ldelf_emit_note_gnu_build_id != NULL && !ldelf_setup_build_id (abfd))) { free ((char *) ldelf_emit_note_gnu_build_id); ldelf_emit_note_gnu_build_id = NULL; } + + if (abfd == NULL + || (ldelf_emit_note_fdo_package_metadata != NULL && !ldelf_setup_package_metadata (abfd))) + { + free ((char *) ldelf_emit_note_fdo_package_metadata); + ldelf_emit_note_fdo_package_metadata = NULL; + } } get_elf_backend_data (link_info.output_bfd)->setup_gnu_properties (&link_info); @@ -1501,6 +1515,124 @@ ldelf_setup_build_id (bfd *ibfd) return false; } +static bool +write_package_metadata (bfd *abfd) +{ + struct elf_obj_tdata *t = elf_tdata (abfd); + const char *json; + asection *asec; + Elf_Internal_Shdr *i_shdr; + unsigned char *contents, *json_bits; + bfd_size_type size; + file_ptr position; + Elf_External_Note *e_note; + + json = t->o->package_metadata.json; + asec = t->o->package_metadata.sec; + if (bfd_is_abs_section (asec->output_section)) + { + einfo (_("%P: warning: .note.package section discarded," + " --package-metadata ignored\n")); + return true; + } + i_shdr = &elf_section_data (asec->output_section)->this_hdr; + + if (i_shdr->contents == NULL) + { + if (asec->contents == NULL) + asec->contents = (unsigned char *) xmalloc (asec->size); + contents = asec->contents; + } + else + contents = i_shdr->contents + asec->output_offset; + + e_note = (Elf_External_Note *) contents; + size = offsetof (Elf_External_Note, name[sizeof "FDO"]); + size = (size + 3) & -(bfd_size_type) 4; + json_bits = contents + size; + size = asec->size - size; + + /* Clear the package metadata field. */ + memset (json_bits, 0, size); + + bfd_h_put_32 (abfd, sizeof "FDO", &e_note->namesz); + bfd_h_put_32 (abfd, size, &e_note->descsz); + bfd_h_put_32 (abfd, FDO_PACKAGING_METADATA, &e_note->type); + memcpy (e_note->name, "FDO", sizeof "FDO"); + memcpy (json_bits, json, strlen(json)); + + position = i_shdr->sh_offset + asec->output_offset; + size = asec->size; + return (bfd_seek (abfd, position, SEEK_SET) == 0 + && bfd_bwrite (contents, size, abfd) == size); +} + +/* Make .note.package section. + https://systemd.io/ELF_PACKAGE_METADATA/ */ + +bool +ldelf_setup_package_metadata (bfd *ibfd) +{ + asection *s; + bfd_size_type size; + size_t json_length; + flagword flags; + + /* If the option wasn't specified, silently return. */ + if (!ldelf_emit_note_fdo_package_metadata) + return false; + + /* The option was specified, but it's too short/long, log and return. */ + json_length = strlen (ldelf_emit_note_fdo_package_metadata); + if (json_length == 0) + { + einfo (_("%P: warning: --package-metadata is empty, ignoring\n")); + return false; + } + if (json_length > SIZE_MAX) + { + einfo (_("%P: warning: --package-metadata is too long, ignoring\n")); + return false; + } + +#ifdef HAVE_JANSSON + json_error_t json_error; + json_t *json = json_loads (ldelf_emit_note_fdo_package_metadata, 0, &json_error); + if (!json) + { + einfo (_("%P: warning: --package-metadata=%s does not contain valid " + "JSON, ignoring: %s\n"), ldelf_emit_note_fdo_package_metadata, + json_error.text); + return false; + } + else + json_decref (json); +#endif + + size = offsetof (Elf_External_Note, name[sizeof "FDO"]); + size += json_length + 1; + size = (size + 3) & -(bfd_size_type) 4; + + flags = (SEC_ALLOC | SEC_LOAD | SEC_IN_MEMORY + | SEC_LINKER_CREATED | SEC_READONLY | SEC_DATA); + s = bfd_make_section_anyway_with_flags (ibfd, ".note.package", + flags); + if (s != NULL && bfd_set_section_alignment (s, 2)) + { + struct elf_obj_tdata *t = elf_tdata (link_info.output_bfd); + t->o->package_metadata.after_write_object_contents = &write_package_metadata; + t->o->package_metadata.json = ldelf_emit_note_fdo_package_metadata; + t->o->package_metadata.sec = s; + elf_section_type (s) = SHT_NOTE; + s->size = size; + return true; + } + + einfo (_("%P: warning: cannot create .note.package section," + " --package-metadata ignored\n")); + return false; +} + /* Look through an expression for an assignment statement. */ static void diff --git a/ld/ldelf.h b/ld/ldelf.h index efa8b45851c..a3ded3dd04c 100644 --- a/ld/ldelf.h +++ b/ld/ldelf.h @@ -19,6 +19,7 @@ MA 02110-1301, USA. */ extern const char *ldelf_emit_note_gnu_build_id; +extern const char *ldelf_emit_note_fdo_package_metadata; extern void ldelf_after_parse (void); extern bool ldelf_load_symbols (lang_input_statement_type *); @@ -26,6 +27,7 @@ extern void ldelf_before_plugin_all_symbols_read (int, int, int, int, int, const char *); extern void ldelf_after_open (int, int, int, int, int, const char *); extern bool ldelf_setup_build_id (bfd *); +extern bool ldelf_setup_package_metadata (bfd *); extern void ldelf_append_to_separated_string (char **, char *); extern void ldelf_before_allocation (char *, char *, const char *); extern bool ldelf_open_dynamic_archive diff --git a/ld/lexsup.c b/ld/lexsup.c index 82c459adb51..9225f71b3ce 100644 --- a/ld/lexsup.c +++ b/ld/lexsup.c @@ -2144,6 +2144,8 @@ elf_static_list_options (FILE *file) fprintf (file, _("\ --build-id[=STYLE] Generate build ID note\n")); fprintf (file, _("\ + --package-metadata[=JSON] Generate package metadata note\n")); + fprintf (file, _("\ --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]\n\ Compress DWARF debug sections using zlib\n")); #ifdef DEFAULT_FLAG_COMPRESS_DEBUG diff --git a/ld/testsuite/ld-elf/package-note.exp b/ld/testsuite/ld-elf/package-note.exp new file mode 100644 index 00000000000..c4239098691 --- /dev/null +++ b/ld/testsuite/ld-elf/package-note.exp @@ -0,0 +1,45 @@ +# Expect script for --package-note tests. +# Copyright (C) 2022 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 *-*-linux*] + || [istarget arm*-*-uclinuxfdpiceabi] + || [istarget *-*-nacl*] + || [istarget *-*-gnu*]) } then { + return +} + +run_ld_link_tests [list \ + [list \ + "package-note.o" \ + "--package-metadata='{\"foo\":\"bar\"}'" \ + "" \ + "" \ + {start.s} \ + {{readelf {--notes} package-note.rd}} \ + "package-note.o" \ + ] \ +] diff --git a/ld/testsuite/ld-elf/package-note.rd b/ld/testsuite/ld-elf/package-note.rd new file mode 100644 index 00000000000..c65dd21cdac --- /dev/null +++ b/ld/testsuite/ld-elf/package-note.rd @@ -0,0 +1,6 @@ +#... +Displaying notes found in: \.note\.package + Owner Data size Description + FDO 0x00000010 FDO_PACKAGING_METADATA + Packaging Metadata: {"foo":"bar"} +#pass -- 2.35.1