From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by sourceware.org (Postfix) with ESMTPS id 3ACEF398543D for ; Tue, 3 Nov 2020 12:45:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 3ACEF398543D Received: by mail-qk1-x741.google.com with SMTP id b18so14418520qkc.9 for ; Tue, 03 Nov 2020 04:45:47 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:references:from:autocrypt:subject:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=UAF9h/uX/P5SkbyAUvG3I+obDUDSpdQZK9gHqIcwtFU=; b=AtawrTZxVpH/Z08awW1BAOryp6d/isNTcbgDiupiUamMthL1HmGFDEiayRmVzl/HST C3KJ2GlGoFJYgdpj+m9QpKpg/7TR9QAxekYgM+b6JesajPJq4C6dbFmqJvimYhmVXjZV 4N6MBUEppvgbeUEfMgKvxnHWDEZXm+z7jR5H1FM6/L2aTcCsZo24CsK6p2nncth5pll4 8UIUJVnF4jYLTw+IzedmT7pUqeGe9Kb/ACj4de7VH4bEKiq2cnK2iKCUPX26eocgcp4L FTTGaxbyn7zLM0uPQUmyVGZFQMw3hTL+s0DaGS8M6J2mjmVApq104Cp4H5UsOKKd3tbG TuPA== X-Gm-Message-State: AOAM533jOXEH6S6lpQOOERamIy0Duxd1/GkY/RhqnTl65XQdW+5mZNSW XtOSNP1c6FN0Mg0Zj0MY7DGlZzGFVp1lIA== X-Google-Smtp-Source: ABdhPJw62hzDJ//8R3FB5pkqQLX8XiWiZKbm3zc0ZsfdkrNB72j4Ad4Fgmrbu/URBMjj0+fLAFgaNw== X-Received: by 2002:ae9:f444:: with SMTP id z4mr19165878qkl.338.1604407546563; Tue, 03 Nov 2020 04:45:46 -0800 (PST) Received: from [192.168.1.4] ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id q27sm4378580qki.60.2020.11.03.04.45.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Nov 2020 04:45:45 -0800 (PST) To: Florian Weimer , Adhemerval Zanella via Libc-alpha References: <87sg9vnbsf.fsf@oldenburg2.str.redhat.com> From: Adhemerval Zanella Autocrypt: addr=adhemerval.zanella@linaro.org; prefer-encrypt=mutual; keydata= mQINBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABtElBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+iQI3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AquQINBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABiQIfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Subject: Re: [PATCH 22/28] elf: Add extension mechanism to ld.so.cache Message-ID: <010f9832-5287-1004-8c73-a012b3b89c7f@linaro.org> Date: Tue, 3 Nov 2020 09:45:43 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <87sg9vnbsf.fsf@oldenburg2.str.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-8.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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-List-Received-Date: Tue, 03 Nov 2020 12:45:48 -0000 On 30/10/2020 09:22, Florian Weimer wrote: > * Adhemerval Zanella via Libc-alpha: > >>> +/* Print the extension information at the cache at start address >>> + FILE_BASE, of ltength FILE_SIZE bytes. The new-format cache header >> >> s/ltength/length > > Fixed. > >>> + is at CACHE, and the file name for diagnostics is CACHE_NAME. */ >>> +static void >>> +print_extensions (struct cache_extension_all_loaded *ext) >>> +{ >>> + if (ext->sections[cache_extension_tag_generator].base != NULL) >>> + { >>> + fputs (_("Cache generated by: "), stdout); >>> + fwrite (ext->sections[cache_extension_tag_generator].base, 1, >>> + ext->sections[cache_extension_tag_generator].size, stdout); >>> + putchar ('\n'); >>> + } >>> +} >>> + >> >> Ok. Will be the extension tag data always comprised of ascii printable >> characters? > > For the generator extension: Yes. But not for other extensions. > This code only deals with the generator extension. > >>> +/* Size of the cache extension directory. All tags are assumed to be >>> + present. */ >>> +enum >>> + { >>> + cache_extension_size = (offsetof (struct cache_extension, sections) >>> + + (cache_extension_count >>> + * sizeof (struct cache_extension_section))) >>> + }; >>> + >>> +/* Write the cache extensions to FD. The extension directory is >>> + assumed to be located at CACHE_EXTENSION_OFFSET. */ >>> +static void >>> +write_extensions (int fd, uint32_t cache_extension_offset) >>> +{ >>> + assert ((cache_extension_offset % 4) == 0); >> >> Maybe a proper error msg instead of an assert here? > > This is in the cache generator, so it's a code bug if the assert fires, > not corrupted input. Ack. > >>> @@ -435,6 +497,25 @@ save_cache (const char *cache_name) >>> && idx_old < cache_entry_old_count) >>> file_entries->libs[idx_old] = file_entries->libs[idx_old - 1]; >>> >>> + /* Compute the location of the extension directory. This >>> + implementation puts the directory after the string table. The >>> + size computation matches the write calls below. The extension >>> + directory does not exist with format 0, so the value does not >>> + matter. */ >>> + uint32_t extension_offset = 0; >>> + if (opt_format != 2) >>> + extension_offset += file_entries_size; >>> + if (opt_format != 0) >>> + { >>> + if (opt_format != 2) >>> + extension_offset += pad; >>> + extension_offset += file_entries_new_size; >>> + } >> >> Ok, although I think we should be good move the 'opt_format' definition to >> a proper enumeration. > > Can this wait? Something for a future patch? Alright, although it does simplify reading this patchset and the change should most mechanical. > >>> +static bool __attribute__ ((unused)) >> >> Maybe use inline and let the compiler decide? Or the function is >> really duplicate in a lot of places? > > The compiler already decides for static functions and will inline them > if they are only used once. Given the size of the function, I think > that's the appropriate approach here. Ack. > >>> +cache_extension_load (const struct cache_file_new *cache, >>> + const void *file_base, size_t file_size, >>> + struct cache_extension_all_loaded *loaded) >>> +{ >>> + memset (loaded, 0, sizeof (*loaded)); >>> + if (cache->extension_offset == 0) >>> + /* No extensions present. This is not a format error. */ >>> + return true; >>> + if ((cache->extension_offset % 4) != 0) >>> + /* Extension offset is misaligned. */ >>> + return false; >>> + size_t size_tmp; >>> + if (__builtin_add_overflow (cache->extension_offset, >>> + sizeof (struct cache_extension), &size_tmp) >>> + || size_tmp > file_size) >>> + /* Extension extends beyond the end of the file. */ >>> + return false; >>> + const struct cache_extension *ext = file_base + cache->extension_offset; >> >> Maybe we should add an alignment check for 'file_base' as well (to >> avoid unaligned struct member deference)? > > This pointer comes from mmap, so it's not something that can be wrong as > the result of the file data. I could add an assert, but I don't think > this is likely to go wrong. Ack.