From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp4-g21.free.fr (smtp4-g21.free.fr [212.27.42.4]) by sourceware.org (Postfix) with ESMTPS id E75153858D35 for ; Mon, 22 May 2023 19:48:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org E75153858D35 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=free.fr Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=free.fr Received: from [192.168.2.42] (unknown [88.173.63.180]) (Authenticated sender: tgingold@free.fr) by smtp4-g21.free.fr (Postfix) with ESMTPSA id C767E19F746 for ; Mon, 22 May 2023 21:48:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=free.fr; s=smtp-20201208; t=1684784902; bh=0A+diEoEf/jsnlmNdkXB1BSzIEs+hXKnFYeCsxTyNpE=; h=Date:To:From:Subject:From; b=aW2FPejXw3gEnneCPum9FLDgjLg0xMg7Rj/yZ9vXkm+704wPHbPwv4K4xulC9lbEW rUtobls3zpNVsmF049IS8sEOwtMzVWIQQOYf65A6+qjxDpBxPruvmmnaJa8bmiQ3wF fn04zscEohwilQuACpkSYFCIY8pOjrQBuI23xDy2uFnehf1S3K4rrZdGoDHGEWQlp7 BAgTlK/czsFJHhK2jFDS0i0Y9mDXaDxJdPXYjAByd2UT8d/3Tql3Kj5GQSElAftyzu ppu6W80rAQ1Nw5dXEDNIQSu7hPXZlk9/gkP+FGl6TZTX6yMtZbIXhUzhMpEUMVDq4I ye8fdaN+1sNEA== Message-ID: Date: Mon, 22 May 2023 21:48:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Content-Language: en-US To: binutils From: Tristan Gingold Subject: [PATCH v2] pe/coff - add support for base64 encoded long section names Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-10.5 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,GIT_PATCH_0,JMQ_SPF_NEUTRAL,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,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 List-Id: Hello, so new version of the patch, including generation of base64 encoded section name indexes. I was able to assemble the test from PR 30444 (using -mbig-obj to overcome the 2^16 sections number limit). I haven't added a test due to its size. No failures on x86_64-gnu-linux for binutils configured for x86_64-pc-mingw64. Tristan. 2023-05-22 Tristan Gingold PR 30444 * coffcode.h (coff_write_object_contents): Handle base64 encoding on PE. Also check for too large string table. * coffgen.c (extract_long_section_name): New function extracted from ... (make_a_section_from_file): ... here. Add support for base64 long section names. (decode_base64): New function. diff --git a/bfd/coffcode.h b/bfd/coffcode.h index 974c8ad9854..097afe9d16c 100644 --- a/bfd/coffcode.h +++ b/bfd/coffcode.h @@ -3625,18 +3625,54 @@ coff_write_object_contents (bfd * abfd) len = strlen (current->name); if (len > SCNNMLEN) { - /* The s_name field is defined to be NUL-padded but need not be - NUL-terminated. We use a temporary buffer so that we can still - sprintf all eight chars without splatting a terminating NUL - over the first byte of the following member (s_paddr). */ - /* PR 21096: The +20 is to stop a bogus warning from gcc7 about - a possible buffer overflow. */ - char s_name_buf[SCNNMLEN + 1 + 20]; /* An inherent limitation of the /nnnnnnn notation used to indicate the offset of the long name in the string table is that we cannot address entries beyone the ten million byte boundary. */ - if (string_size >= 10000000) + if (string_size < 10000000) + { + /* The s_name field is defined to be NUL-padded but need not + be NUL-terminated. We use a temporary buffer so that we + can still sprintf all eight chars without splatting a + terminating NUL over the first byte of the following + member (s_paddr). */ + /* PR 21096: The +20 is to stop a bogus warning from gcc7 + about a possible buffer overflow. */ + char s_name_buf[SCNNMLEN + 1 + 20]; + + /* We do not need to use snprintf here as we have already + verified that string_size is not too big, plus we have + an overlarge buffer, just in case. */ + sprintf (s_name_buf, "/%lu", (unsigned long) string_size); + /* Then strncpy takes care of any padding for us. */ + strncpy (section.s_name, s_name_buf, SCNNMLEN); + } + else +#ifdef COFF_WITH_PE + { + /* PE use a bae64 encoding for long section names whose + index is very large. */ + static const char base64[] = + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789+/"; + unsigned long off = string_size; + unsigned i; + + section.s_name[0] = '/'; + section.s_name[1] = '/'; + for (i = SCNNMLEN - 1; i >=2; i--) + { + section.s_name[i] = base64[off & 0x3f]; + off >>= 6; + } + } +#endif + if (string_size > 0xffffffffUL - (len + 1) +#ifndef COFF_WITH_PE + || string_size >= 10000000 +#endif + ) { bfd_set_error (bfd_error_file_too_big); _bfd_error_handler @@ -3646,12 +3682,6 @@ coff_write_object_contents (bfd * abfd) return false; } - /* We do not need to use snprintf here as we have already verfied - that string_size is not too big, plus we have an overlarge - buffer, just in case. */ - sprintf (s_name_buf, "/%lu", (unsigned long) string_size); - /* Then strncpy takes care of any padding for us. */ - strncpy (section.s_name, s_name_buf, SCNNMLEN); string_size += len + 1; long_section_names = true; } diff --git a/bfd/coffgen.c b/bfd/coffgen.c index ac936def566..970e06bf2c0 100644 --- a/bfd/coffgen.c +++ b/bfd/coffgen.c @@ -43,6 +43,69 @@ #include "coff/internal.h" #include "libcoff.h" +/* Extract a long section name at STRINDEX and copy it to the bfd objstack. + Return NULL in case of error. */ + +static char * +extract_long_section_name(bfd *abfd, unsigned long strindex) +{ + const char *strings; + char *name; + + strings = _bfd_coff_read_string_table (abfd); + if (strings == NULL) + return NULL; + if ((bfd_size_type)(strindex + 2) >= obj_coff_strings_len (abfd)) + return NULL; + strings += strindex; + name = (char *) bfd_alloc (abfd, (bfd_size_type) strlen (strings) + 1); + if (name == NULL) + return NULL; + strcpy (name, strings); + + return name; +} + +/* Decode a base64 coded string at STR of length LEN, and write the result + to RES. Return true on success. + Return false in case of invalid character or overflow. */ + +static bool +decode_base64 (const char *str, unsigned len, uint32_t *res) +{ + unsigned i; + uint32_t val; + + val = 0; + for (i = 0; i < len; i++) + { + char c = str[i]; + unsigned d; + + if (c >= 'A' && c <= 'Z') + d = c - 'A'; + else if (c >= 'a' && c <= 'z') + d = c - 'a' + 26; + else if (c >= '0' && c <= '9') + d = c - '0' + 52; + else if (c == '+') + d = 62; + else if (c == '/') + d = 63; + else + return false; + + /* Check for overflow. */ + if ((val >> 26) != 0) + return false; + + val = (val << 6) + d; + } + + *res = val; + return true; +} + /* Take a section header read from a coff file (in HOST byte order), and make a BFD "section" out of it. This is used by ECOFF. */ @@ -67,32 +130,46 @@ make_a_section_from_file (bfd *abfd, if (bfd_coff_set_long_section_names (abfd, bfd_coff_long_section_names (abfd)) && hdr->s_name[0] == '/') { - char buf[SCNNMLEN]; - long strindex; - char *p; - const char *strings; - /* Flag that this BFD uses long names, even though the format might expect them to be off by default. This won't directly affect the format of any output BFD created from this one, but the information can be used to decide what to do. */ bfd_coff_set_long_section_names (abfd, true); - memcpy (buf, hdr->s_name + 1, SCNNMLEN - 1); - buf[SCNNMLEN - 1] = '\0'; - strindex = strtol (buf, &p, 10); - if (*p == '\0' && strindex >= 0) + + if (hdr->s_name[1] == '/') { - strings = _bfd_coff_read_string_table (abfd); - if (strings == NULL) - return false; - if ((bfd_size_type)(strindex + 2) >= obj_coff_strings_len (abfd)) + /* LLVM extension: the '/' is followed by another '/' and then by + the index in the strtab encoded in base64 without NUL at the + end. */ + uint32_t strindex; + + /* Decode the index. No overflow is expected as the string table + length is at most 2^32 - 1 (the length is written on the first + four bytes). */ + if (!decode_base64 (hdr->s_name + 2, SCNNMLEN - 2, &strindex)) return false; - strings += strindex; - name = (char *) bfd_alloc (abfd, - (bfd_size_type) strlen (strings) + 1 + 1); + + name = extract_long_section_name (abfd, strindex); if (name == NULL) return false; - strcpy (name, strings); + } + else + { + /* PE classic long section name. The '/' is followed by the index + in the strtab. The index is formatted as a decimal string. */ + char buf[SCNNMLEN]; + long strindex; + char *p; + + memcpy (buf, hdr->s_name + 1, SCNNMLEN - 1); + buf[SCNNMLEN - 1] = '\0'; + strindex = strtol (buf, &p, 10); + if (*p == '\0' && strindex >= 0) + { + name = extract_long_section_name (abfd, strindex); + if (name == NULL) + return false; + } } }