From patchwork Tue Mar 1 16:17:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 1599457 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.a=rsa-sha256 header.s=default header.b=hJyGj7Qc; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4K7MsJ64xRz9sG3 for ; Wed, 2 Mar 2022 03:19:48 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 431C5385841C for ; Tue, 1 Mar 2022 16:19:46 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 431C5385841C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1646151586; bh=dCzZFJXfBxDmt8SOS2VZlEe3TAQ+pSff6iGxPcjFtkQ=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=hJyGj7Qc2Wiz7qsvDT4QgP6RsR7H2DtL60VWbK0NShJq3ZUaGRrv4+mkz94frzQ4G sstresjfF+Ryt2512cfVZRyUj8ox8vCvCfCmfCbsQuEmeRHKHJWUfu6gfhQghgluOJ h+cG/KBZWX+P/fiA8JI1APjPD2b8xBLEzsQmg8JA= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by sourceware.org (Postfix) with ESMTPS id E9ED6385841C for ; Tue, 1 Mar 2022 16:17:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E9ED6385841C Received: by mail-pg1-x536.google.com with SMTP id 27so14738734pgk.10 for ; Tue, 01 Mar 2022 08:17:10 -0800 (PST) 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=dCzZFJXfBxDmt8SOS2VZlEe3TAQ+pSff6iGxPcjFtkQ=; b=MpO3SBuNE83SgrxD47Rrgphu/xOgcRYlU7MBwUvYnrXioZxS3PW2I5EcEB8HMPvSrv gRqNTj0UCwMBtGkYAiGxBexrnSolMGl1qZAQoHn13KJ9SZrmVyvVtxUN9GCyT54IQ17Z RyH79wUruZyBWCyx588NAh77EnXEcYCOt/mhusFHBXKZD0+d4fH/GvI/0ehmvNo1Jy9B gxu8TgECVQPQAaeBwfmC5O94FXgFzsBeMuMkw21kcSnQCNrySuu1w8/Xt9H1PaX6GK9E 5ojdi2jpK2AR3LYqoUiAebA+1c+Aq9D6HYKHMzTni/ANDNjfZs1NynEmwMpDEh4RNniE A2wQ== X-Gm-Message-State: AOAM532ywGjbGcefjC0j/8mbKv6ZGh30B5TxHpYsfFacoHs7C3K2cEUe haB94QqBIyhMsyV7ykezkZs= X-Google-Smtp-Source: ABdhPJxEIyHDrVeix6Brkd0FL4DYat+yjzDCCQTvoIdiM25C/viTw2leryuV/FVHRJTL2ICKn5SQtQ== X-Received: by 2002:a05:6a00:26e0:b0:4e1:7131:de2b with SMTP id p32-20020a056a0026e000b004e17131de2bmr28262636pfw.20.1646151429889; Tue, 01 Mar 2022 08:17:09 -0800 (PST) Received: from gnu-tgl-3.localdomain ([172.58.35.88]) by smtp.gmail.com with ESMTPSA id t11-20020a056a0021cb00b004ce1a7d5ce8sm18051866pfj.113.2022.03.01.08.17.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Mar 2022 08:17:08 -0800 (PST) Received: from gnu-tgl-3.. (localhost [IPv6:::1]) by gnu-tgl-3.localdomain (Postfix) with ESMTP id 97D34C04BB; Tue, 1 Mar 2022 08:17:07 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v4 3/5] Add GLIBC_ABI_DT_RELR for DT_RELR support Date: Tue, 1 Mar 2022 08:17:04 -0800 Message-Id: <20220301161706.185216-4-hjl.tools@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220301161706.185216-1-hjl.tools@gmail.com> References: <20220301161706.185216-1-hjl.tools@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-3028.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE, URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: "H.J. Lu via Libc-alpha" From: "H.J. Lu" Reply-To: "H.J. Lu" Cc: Joseph Myers Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" The EI_ABIVERSION field of the ELF header in executables and shared libraries can be bumped to indicate the minimum ABI requirement on the dynamic linker. However, EI_ABIVERSION in executables isn't checked by the Linux kernel ELF loader nor the existing dynamic linker. Executables will crash mysteriously if the dynamic linker doesn't support the ABI features required by the EI_ABIVERSION field. The dynamic linker should be changed to check EI_ABIVERSION in executables. Add a glibc version, GLIBC_ABI_DT_RELR, to indicate DT_RELR support so that the existing dynamic linkers will issue an error on executables with GLIBC_ABI_DT_RELR dependency. Issue an error if there is a DT_RELR entry without GLIBC_ABI_DT_RELR dependency nor GLIBC_PRIVATE definition. Support __placeholder_only_for_empty_version_map as the placeholder symbol used only for empty version map to generate GLIBC_ABI_DT_RELR without any symbols. --- elf/Makefile | 16 ++++++++++++++-- elf/Versions | 5 +++++ elf/dl-version.c | 33 +++++++++++++++++++++++++++++++-- elf/libc-abi-version.exp | 1 + include/link.h | 6 ++++++ scripts/abilist.awk | 2 ++ scripts/versions.awk | 7 ++++++- 7 files changed, 65 insertions(+), 5 deletions(-) create mode 100644 elf/libc-abi-version.exp diff --git a/elf/Makefile b/elf/Makefile index fd462ba315..f533d377fd 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -1113,8 +1113,10 @@ $(eval $(call include_dsosort_tests,dso-sort-tests-1.def)) $(eval $(call include_dsosort_tests,dso-sort-tests-2.def)) endif -check-abi: $(objpfx)check-abi-ld.out -tests-special += $(objpfx)check-abi-ld.out +check-abi: $(objpfx)check-abi-ld.out \ + $(objpfx)check-abi-version-libc.out +tests-special += $(objpfx)check-abi-ld.out \ + $(objpfx)check-abi-version-libc.out update-abi: update-abi-ld update-all-abi: update-all-abi-ld @@ -2739,3 +2741,13 @@ $(objpfx)check-tst-relr-pie.out: $(objpfx)tst-relr-pie | sed -ne '/required from libc.so/,$$ p' \ | grep GLIBC_ABI_DT_RELR > $@; \ $(evaluate-test) + +$(objpfx)check-abi-version-libc.out: libc-abi-version.exp \ + $(objpfx)libc.symlist-abi-version + cmp $^ > $@; \ + $(evaluate-test) + +$(objpfx)libc.symlist-abi-version: $(common-objpfx)libc.so + LC_ALL=C $(OBJDUMP) --dynamic-syms $< | grep " GLIBC_ABI_" \ + | sed "s/0\+/00000000/g;s/[ \t]\+/ /g" > $@T + mv -f $@T $@ diff --git a/elf/Versions b/elf/Versions index 8bed855d8c..a9ff278de7 100644 --- a/elf/Versions +++ b/elf/Versions @@ -23,6 +23,11 @@ libc { GLIBC_2.35 { _dl_find_object; } + GLIBC_ABI_DT_RELR { + # This symbol is used only for empty version map and will be removed + # by scripts/versions.awk. + __placeholder_only_for_empty_version_map; + } GLIBC_PRIVATE { # functions used in other libraries __libc_early_init; diff --git a/elf/dl-version.c b/elf/dl-version.c index b47bd91727..720ec596a5 100644 --- a/elf/dl-version.c +++ b/elf/dl-version.c @@ -214,12 +214,20 @@ _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) while (1) { /* Match the symbol. */ + const char *string = strtab + aux->vna_name; result |= match_symbol (DSO_FILENAME (map->l_name), map->l_ns, aux->vna_hash, - strtab + aux->vna_name, - needed->l_real, verbose, + string, needed->l_real, verbose, aux->vna_flags & VER_FLG_WEAK); + if (map->l_abi_version == lav_none + /* 0xfd0e42: _dl_elf_hash ("GLIBC_ABI_DT_RELR"). */ + && aux->vna_hash == 0xfd0e42 + && __glibc_likely (strcmp (string, + "GLIBC_ABI_DT_RELR") + == 0)) + map->l_abi_version = lav_dt_relr_ref; + /* Compare the version index. */ if ((unsigned int) (aux->vna_other & 0x7fff) > ndx_high) ndx_high = aux->vna_other & 0x7fff; @@ -253,6 +261,16 @@ _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr); while (1) { + /* 0x0963cf85: _dl_elf_hash ("GLIBC_PRIVATE"). */ + if (ent->vd_hash == 0x0963cf85) + { + ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) ent + + ent->vd_aux); + if (__glibc_likely (strcmp ("GLIBC_PRIVATE", + strtab + aux->vda_name) == 0)) + map->l_abi_version = lav_private_def; + } + if ((unsigned int) (ent->vd_ndx & 0x7fff) > ndx_high) ndx_high = ent->vd_ndx & 0x7fff; @@ -352,6 +370,17 @@ _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) } } + /* Issue an error if there is a DT_RELR entry without GLIBC_ABI_DT_RELR + dependency nor GLIBC_PRIVATE definition. */ + if (map->l_info[DT_RELR] != NULL + && __glibc_unlikely (map->l_abi_version == lav_none)) + { + _dl_exception_create + (&exception, DSO_FILENAME (map->l_name), + N_("DT_RELR without GLIBC_ABI_DT_RELR dependency")); + goto call_error; + } + return result; } diff --git a/elf/libc-abi-version.exp b/elf/libc-abi-version.exp new file mode 100644 index 0000000000..ff8506b3ba --- /dev/null +++ b/elf/libc-abi-version.exp @@ -0,0 +1 @@ +00000000 g DO *ABS* 00000000 GLIBC_ABI_DT_RELR GLIBC_ABI_DT_RELR diff --git a/include/link.h b/include/link.h index 03db14c7b0..8ec5e35cf2 100644 --- a/include/link.h +++ b/include/link.h @@ -177,6 +177,12 @@ struct link_map lt_library, /* Library needed by main executable. */ lt_loaded /* Extra run-time loaded shared object. */ } l_type:2; + enum /* ABI dependency of this object. */ + { + lav_none, /* No ABI dependency. */ + lav_dt_relr_ref, /* Need GLIBC_ABI_DT_RELR. */ + lav_private_def /* Define GLIBC_PRIVATE. */ + } l_abi_version:2; unsigned int l_relocated:1; /* Nonzero if object's relocations done. */ unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */ unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */ diff --git a/scripts/abilist.awk b/scripts/abilist.awk index 24a34ccbed..6cc7af6ac8 100644 --- a/scripts/abilist.awk +++ b/scripts/abilist.awk @@ -55,6 +55,8 @@ $2 == "g" || $2 == "w" && (NF == 7 || NF == 8) { # caused STV_HIDDEN symbols to appear in .dynsym, though that is useless. if (NF > 7 && $7 == ".hidden") next; + if (version ~ /^GLIBC_ABI_/ && !include_abi_version) next; + if (version == "GLIBC_PRIVATE" && !include_private) next; desc = ""; diff --git a/scripts/versions.awk b/scripts/versions.awk index 357ad1355e..d70b07bd1a 100644 --- a/scripts/versions.awk +++ b/scripts/versions.awk @@ -185,8 +185,13 @@ END { closeversion(oldver, veryoldver); veryoldver = oldver; } - printf("%s {\n global:\n", $2) > outfile; oldver = $2; + # Skip the placeholder symbol used only for empty version map. + if ($3 == "__placeholder_only_for_empty_version_map;") { + printf("%s {\n", $2) > outfile; + continue; + } + printf("%s {\n global:\n", $2) > outfile; } printf(" ") > outfile; for (n = 3; n <= NF; ++n) {