From patchwork Tue Dec 21 15:06:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 49150 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 15C0E3858438 for ; Tue, 21 Dec 2021 15:08:11 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 15C0E3858438 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1640099291; bh=vzudlVICs35gnMSFQrpfR81AVXPAPeU/mcMd6Q1yirc=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=l00lE8F4WWVVzE/IIHDHEvKWRMsD1FOaI31yGmXoeP5M/fgm53NU1c4KaZFWC99Mh wSswRRr6a2nkKviSAbPR73dlQQ5CwM5pCfptpd4lWwK0j6p1GHhUpcAbn5Rgx7EWwv 0+et9kSrua38DtvPopH4ERdIRbkWB/mSNTNX3vfw= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by sourceware.org (Postfix) with ESMTPS id 28C423858401 for ; Tue, 21 Dec 2021 15:07:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 28C423858401 Received: by mail-pl1-x62f.google.com with SMTP id v19so10958169plo.7 for ; Tue, 21 Dec 2021 07:07:04 -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:subject:date:message-id:mime-version :content-transfer-encoding; bh=vzudlVICs35gnMSFQrpfR81AVXPAPeU/mcMd6Q1yirc=; b=teOR8oIVbQp77Ue7P5uhtRMgZLHvapCu7CZg4LhGUs5d0mSoQkJ0oE39hEH6WFEBKL LqIWYAV1gcPyps2xKCGU4Sbi0vMYGSFGXNEwhPa9BkFYwi03vRaz8ESBd8IDqX67uOfB 6Uio3tspDCd/m1og1JxasCqIMtizz/KuexlSwQjXUgpJn1bvU34d8brUEunNGGvtZZN3 N4ISvgpPVFMT9pN9EdeOWBjSkgkh4T7p5wUMgj2OX2eovsWRkgDvB6wcdq9eq9/vspCX Svz/FPE1LNHDlC8wWPoWnyM7v2jL0hRxRfEZ/4m3lreP6EAnxX5FumR/rorLydW8PMBS WPlA== X-Gm-Message-State: AOAM533EGi0Ej4EK+2bFIMdXikofoEjrWQGMcM7tVUbXM9WswB7nL7el RgCbD4yvvuI2CqCETukrjZSy7rNL4p4= X-Google-Smtp-Source: ABdhPJyEJxabqgd4NhBXvVgJXnrf1Gi2UtQiWoJKYlLy9AMTQ36hFLAS3jsRMr39Ty2mwNaYAxnESQ== X-Received: by 2002:a17:903:1210:b0:148:a2e7:fb2a with SMTP id l16-20020a170903121000b00148a2e7fb2amr3753540plh.107.1640099222902; Tue, 21 Dec 2021 07:07:02 -0800 (PST) Received: from gnu-tgl-3.localdomain ([172.58.35.133]) by smtp.gmail.com with ESMTPSA id d11sm15291638pfv.17.2021.12.21.07.07.02 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Dec 2021 07:07:02 -0800 (PST) Received: from gnu-tgl-2.localdomain (gnu-tgl-2 [192.168.1.42]) by gnu-tgl-3.localdomain (Postfix) with ESMTPS id 4BBD9C0722 for ; Tue, 21 Dec 2021 07:07:01 -0800 (PST) Received: from gnu-tgl-2.. (localhost [IPv6:::1]) by gnu-tgl-2.localdomain (Postfix) with ESMTP id 339F73003DA for ; Tue, 21 Dec 2021 07:07:00 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v4 1/2] elf: Properly align all PT_LOAD segments [BZ #28676] Date: Tue, 21 Dec 2021 07:06:59 -0800 Message-Id: <20211221150700.1595916-1-hjl.tools@gmail.com> X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 X-Spam-Status: No, score=-3029.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP 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" Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" Linker may set p_align of a PT_LOAD segment larger than p_align of the first PT_LOAD segment to satisfy a section alignment: Elf file type is DYN (Shared object file) Entry point 0x0 There are 10 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000834 0x0000000000000834 R E 0x1000 LOAD 0x0000000000000e00 0x0000000000001e00 0x0000000000001e00 0x0000000000000230 0x0000000000000230 RW 0x1000 LOAD 0x0000000000400000 0x0000000000400000 0x0000000000400000 0x0000000000000004 0x0000000000000008 RW 0x400000 ... Section to Segment mapping: Segment Sections... 00 .note.gnu.property .note.gnu.build-id .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .plt.got .text .fini .rodata .eh_frame_hdr .eh_frame 01 .init_array .fini_array .data.rel.ro .dynamic .got .got.plt 02 .data .bss We should align the first PT_LOAD segment to the maximum p_align of all PT_LOAD segments, similar to the kernel commit: commit ce81bb256a224259ab686742a6284930cbe4f1fa Author: Chris Kennelly Date: Thu Oct 15 20:12:32 2020 -0700 fs/binfmt_elf: use PT_LOAD p_align values for suitable start address --- elf/dl-load.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/elf/dl-load.c b/elf/dl-load.c index 721593135e..e61515771a 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1101,6 +1101,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, size_t nloadcmds = 0; bool has_holes = false; bool empty_dynamic = false; + ElfW(Addr) p_align_max = 0; /* The struct is initialized to zero so this is not necessary: l->l_ld = 0; @@ -1151,7 +1152,9 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, c->mapend = ALIGN_UP (ph->p_vaddr + ph->p_filesz, GLRO(dl_pagesize)); c->dataend = ph->p_vaddr + ph->p_filesz; c->allocend = ph->p_vaddr + ph->p_memsz; - c->mapalign = ph->p_align; + /* Remember the maximum p_align. */ + if (ph->p_align > p_align_max) + p_align_max = ph->p_align; c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize)); /* Determine whether there is a gap between the last segment @@ -1226,6 +1229,10 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, goto lose; } + /* Align all PT_LOAD segments to the maximum p_align. */ + for (size_t i = 0; i < nloadcmds; i++) + loadcmds[i].mapalign = p_align_max; + /* dlopen of an executable is not valid because it is not possible to perform proper relocations, handle static TLS, or run the ELF constructors. For PIE, the check needs the dynamic