From patchwork Mon Jun 22 15:13:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 39737 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 17C8738930E0; Mon, 22 Jun 2020 15:14:06 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 17C8738930E0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1592838846; bh=HFWPUaJPoatQnF8ZdDJcVk0PF6dw6uGkuMlew4jtE5s=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=KCMCX7uu69VZNy60nNvGqsD93c6/o0Q9rx9xzRKBusCdTCeoXqEjD9vTkBHNk5Owu hfhpPdVh3kcdK7GnyevJIDbqn2SIdgtzSEWKe8GPMcwTSViZf2xxD2T6WuOcgsSvR2 BN9gjl7dqpPmRU5ISXE3O2kaKynEseHK0rEigvq8= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by sourceware.org (Postfix) with ESMTP id AEE6F3870840 for ; Mon, 22 Jun 2020 15:14:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org AEE6F3870840 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-201-a4-NGvmdN_uvDkB76U0lWw-1; Mon, 22 Jun 2020 11:13:59 -0400 X-MC-Unique: a4-NGvmdN_uvDkB76U0lWw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 75C9319057D8 for ; Mon, 22 Jun 2020 15:13:38 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-112-185.ams2.redhat.com [10.36.112.185]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 934FC7167F for ; Mon, 22 Jun 2020 15:13:37 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 06/30] elf: Extract command-line/environment variables state from rtld.c In-Reply-To: References: Message-Id: <041345fbb6b211068964376cfcc976d418df323f.1592836143.git.fweimer@redhat.com> Date: Mon, 22 Jun 2020 17:13:35 +0200 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-13.7 required=5.0 tests=BAYES_00, DKIM_INVALID, DKIM_SIGNED, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, 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-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Introduce struct dl_main_state and move it to . This avoids the need for putting state that is only needed during startup into the ld.so data segment. --- elf/dl-main.h | 95 +++++++++++++++++++++++++++++++ elf/rtld.c | 153 +++++++++++++++++++------------------------------- 2 files changed, 153 insertions(+), 95 deletions(-) create mode 100644 elf/dl-main.h diff --git a/elf/dl-main.h b/elf/dl-main.h new file mode 100644 index 0000000000..ad9250171f --- /dev/null +++ b/elf/dl-main.h @@ -0,0 +1,95 @@ +/* Information collection during ld.so startup. + Copyright (C) 1995-2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef _DL_MAIN +#define _DL_MAIN + +#include + +/* Length limits for names and paths, to protect the dynamic linker, + particularly when __libc_enable_secure is active. */ +#ifdef NAME_MAX +# define SECURE_NAME_LIMIT NAME_MAX +#else +# define SECURE_NAME_LIMIT 255 +#endif +#ifdef PATH_MAX +# define SECURE_PATH_LIMIT PATH_MAX +#else +# define SECURE_PATH_LIMIT 1024 +#endif + +/* Strings containing colon-separated lists of audit modules. */ +struct audit_list +{ + /* Array of strings containing colon-separated path lists. Each + audit module needs its own namespace, so pre-allocate the largest + possible list. */ + const char *audit_strings[DL_NNS]; + + /* Number of entries added to audit_strings. */ + size_t length; + + /* Index into the audit_strings array (for the iteration phase). */ + size_t current_index; + + /* Tail of audit_strings[current_index] which still needs + processing. */ + const char *current_tail; + + /* Scratch buffer for returning a name which is part of the strings + in audit_strings. */ + char fname[SECURE_NAME_LIMIT]; +}; + +/* This is a list of all the modes the dynamic loader can be in. */ +enum mode { normal, list, verify, trace }; + +/* Aggregated state information extracted from environment variables + and the ld.so command line. */ +struct dl_main_state +{ + struct audit_list audit_list; + + /* The library search path. */ + const char *library_path; + + /* The list preloaded objects from LD_PRELOAD. */ + const char *preloadlist; + + /* The preload list passed as a command argument. */ + const char *preloadarg; + + enum mode mode; + + /* True if any of the debugging options is enabled. */ + bool any_debug; + + /* True if information about versions has to be printed. */ + bool version_info; +}; + +/* Helper function to invoke _dl_init_paths with the right arguments + from *STATE. */ +static inline void +call_init_paths (const struct dl_main_state *state) +{ + _dl_init_paths (state->library_path); +} + +#endif /* _DL_MAIN */ diff --git a/elf/rtld.c b/elf/rtld.c index 882b070cc0..e3556eabc4 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -47,6 +47,7 @@ #include #include #include +#include #include @@ -111,42 +112,6 @@ static void print_missing_version (int errcode, const char *objname, /* Print the various times we collected. */ static void print_statistics (const hp_timing_t *total_timep); -/* Length limits for names and paths, to protect the dynamic linker, - particularly when __libc_enable_secure is active. */ -#ifdef NAME_MAX -# define SECURE_NAME_LIMIT NAME_MAX -#else -# define SECURE_NAME_LIMIT 255 -#endif -#ifdef PATH_MAX -# define SECURE_PATH_LIMIT PATH_MAX -#else -# define SECURE_PATH_LIMIT 1024 -#endif - -/* Strings containing colon-separated lists of audit modules. */ -struct audit_list -{ - /* Array of strings containing colon-separated path lists. Each - audit module needs its own namespace, so pre-allocate the largest - possible list. */ - const char *audit_strings[DL_NNS]; - - /* Number of entries added to audit_strings. */ - size_t length; - - /* Index into the audit_strings array (for the iteration phase). */ - size_t current_index; - - /* Tail of audit_strings[current_index] which still needs - processing. */ - const char *current_tail; - - /* Scratch buffer for returning a name which is part of the strings - in audit_strings. */ - char fname[SECURE_NAME_LIMIT]; -}; - /* Creates an empty audit list. */ static void audit_list_init (struct audit_list *); @@ -167,13 +132,13 @@ static void audit_list_add_dynamic_tag (struct audit_list *, audit_list_add_dynamic_tags calls. */ static const char *audit_list_next (struct audit_list *); -/* This is a list of all the modes the dynamic loader can be in. */ -enum mode { normal, list, verify, trace }; +/* Initialize *STATE with the defaults. */ +static void dl_main_state_init (struct dl_main_state *state); /* Process all environments variables the dynamic linker must recognize. Since all of them start with `LD_' we are a bit smarter while finding all the entries. */ -static void process_envvars (enum mode *modep, struct audit_list *); +static void process_envvars (struct dl_main_state *state); #ifdef DL_ARGV_NOT_RELRO int _dl_argc attribute_hidden; @@ -299,6 +264,18 @@ audit_list_next (struct audit_list *list) } } +static void +dl_main_state_init (struct dl_main_state *state) +{ + audit_list_init (&state->audit_list); + state->library_path = NULL; + state->preloadlist = NULL; + state->preloadarg = NULL; + state->mode = normal; + state->any_debug = false; + state->version_info = false; +} + #ifndef HAVE_INLINED_SYSCALLS /* Set nonzero during loading and initialization of executable and libraries, cleared before the executable's entry point runs. This @@ -880,15 +857,6 @@ security_init (void) #include -/* The library search path. */ -static const char *library_path attribute_relro; -/* The list preloaded objects. */ -static const char *preloadlist attribute_relro; -/* Nonzero if information about versions has to be printed. */ -static int version_info attribute_relro; -/* The preload list passed as a command argument. */ -static const char *preloadarg attribute_relro; - /* The LD_PRELOAD environment variable gives list of libraries separated by white space or colons that are loaded before the executable's dependencies and prepended to the global scope list. @@ -1130,7 +1098,6 @@ dl_main (const ElfW(Phdr) *phdr, ElfW(auxv_t) *auxv) { const ElfW(Phdr) *ph; - enum mode mode; struct link_map *main_map; size_t file_size; char *file; @@ -1140,8 +1107,8 @@ dl_main (const ElfW(Phdr) *phdr, bool rtld_is_main = false; void *tcbp = NULL; - struct audit_list audit_list; - audit_list_init (&audit_list); + struct dl_main_state state; + dl_main_state_init (&state); GL(dl_init_static_tls) = &_dl_nothread_init_static_tls; @@ -1156,7 +1123,7 @@ dl_main (const ElfW(Phdr) *phdr, GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable; /* Process the environment variable which control the behaviour. */ - process_envvars (&mode, &audit_list); + process_envvars (&state); #ifndef HAVE_INLINED_SYSCALLS /* Set up a flag which tells we are just starting. */ @@ -1188,7 +1155,7 @@ dl_main (const ElfW(Phdr) *phdr, while (_dl_argc > 1) if (! strcmp (_dl_argv[1], "--list")) { - mode = list; + state.mode = list; GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */ ++_dl_skip_args; @@ -1197,7 +1164,7 @@ dl_main (const ElfW(Phdr) *phdr, } else if (! strcmp (_dl_argv[1], "--verify")) { - mode = verify; + state.mode = verify; ++_dl_skip_args; --_dl_argc; @@ -1213,7 +1180,7 @@ dl_main (const ElfW(Phdr) *phdr, else if (! strcmp (_dl_argv[1], "--library-path") && _dl_argc > 2) { - library_path = _dl_argv[2]; + state.library_path = _dl_argv[2]; _dl_skip_args += 2; _dl_argc -= 2; @@ -1230,7 +1197,7 @@ dl_main (const ElfW(Phdr) *phdr, } else if (! strcmp (_dl_argv[1], "--audit") && _dl_argc > 2) { - audit_list_add_string (&audit_list, _dl_argv[2]); + audit_list_add_string (&state.audit_list, _dl_argv[2]); _dl_skip_args += 2; _dl_argc -= 2; @@ -1238,7 +1205,7 @@ dl_main (const ElfW(Phdr) *phdr, } else if (! strcmp (_dl_argv[1], "--preload") && _dl_argc > 2) { - preloadarg = _dl_argv[2]; + state.preloadarg = _dl_argv[2]; _dl_skip_args += 2; _dl_argc -= 2; _dl_argv += 2; @@ -1297,7 +1264,7 @@ of this helper program; chances are you did not intend to run this program.\n\ break; } - if (__builtin_expect (mode, normal) == verify) + if (__builtin_expect (state.mode, normal) == verify) { const char *objname; const char *err_str = NULL; @@ -1326,7 +1293,7 @@ of this helper program; chances are you did not intend to run this program.\n\ /* Now the map for the main executable is available. */ main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded; - if (__builtin_expect (mode, normal) == normal + if (__builtin_expect (state.mode, normal) == normal && GL(dl_rtld_map).l_info[DT_SONAME] != NULL && main_map->l_info[DT_SONAME] != NULL && strcmp ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB]) @@ -1563,7 +1530,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); _dl_setup_hash (main_map); } - if (__builtin_expect (mode, normal) == verify) + if (__builtin_expect (state.mode, normal) == verify) { /* We were called just to verify that this is a dynamic executable using us as the program interpreter. Exit with an @@ -1593,7 +1560,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); /* Initialize the data structures for the search paths for shared objects. */ - _dl_init_paths (library_path); + call_init_paths (&state); /* Initialize _r_debug. */ struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr, @@ -1658,12 +1625,12 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); /* Assign a module ID. Do this before loading any audit modules. */ GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid (); - audit_list_add_dynamic_tag (&audit_list, main_map, DT_AUDIT); - audit_list_add_dynamic_tag (&audit_list, main_map, DT_DEPAUDIT); + audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_AUDIT); + audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_DEPAUDIT); /* If we have auditing DSOs to load, do it now. */ bool need_security_init = true; - if (audit_list.length > 0) + if (state.audit_list.length > 0) { /* Since we start using the auditing DSOs right away we need to initialize the data structures now. */ @@ -1676,7 +1643,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); security_init (); need_security_init = false; - load_audit_modules (main_map, &audit_list); + load_audit_modules (main_map, &state.audit_list); } /* Keep track of the currently loaded modules to count how many @@ -1727,19 +1694,21 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); struct link_map **preloads = NULL; unsigned int npreloads = 0; - if (__glibc_unlikely (preloadlist != NULL)) + if (__glibc_unlikely (state.preloadlist != NULL)) { RTLD_TIMING_VAR (start); rtld_timer_start (&start); - npreloads += handle_preload_list (preloadlist, main_map, "LD_PRELOAD"); + npreloads += handle_preload_list (state.preloadlist, main_map, + "LD_PRELOAD"); rtld_timer_accum (&load_time, start); } - if (__glibc_unlikely (preloadarg != NULL)) + if (__glibc_unlikely (state.preloadarg != NULL)) { RTLD_TIMING_VAR (start); rtld_timer_start (&start); - npreloads += handle_preload_list (preloadarg, main_map, "--preload"); + npreloads += handle_preload_list (state.preloadarg, main_map, + "--preload"); rtld_timer_accum (&load_time, start); } @@ -1846,7 +1815,8 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); { RTLD_TIMING_VAR (start); rtld_timer_start (&start); - _dl_map_object_deps (main_map, preloads, npreloads, mode == trace, 0); + _dl_map_object_deps (main_map, preloads, npreloads, + state.mode == trace, 0); rtld_timer_accum (&load_time, start); } @@ -1873,7 +1843,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); rtld_multiple_ref = true; GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1]; - if (__builtin_expect (mode, normal) == normal) + if (__builtin_expect (state.mode, normal) == normal) { GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist ? main_map->l_searchlist.r_list[i + 1] @@ -1906,8 +1876,8 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); versions we need. */ { struct version_check_args args; - args.doexit = mode == normal; - args.dotrace = mode == trace; + args.doexit = state.mode == normal; + args.dotrace = state.mode == trace; _dl_receive_error (print_missing_version, version_check_doit, &args); } @@ -1927,7 +1897,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); earlier. */ security_init (); - if (__builtin_expect (mode, normal) != normal) + if (__builtin_expect (state.mode, normal) != normal) { /* We were run just to list the shared libraries. It is important that we do this before real relocation, because the @@ -2029,7 +1999,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); (size_t) l->l_map_start); } - if (__builtin_expect (mode, trace) != trace) + if (__builtin_expect (state.mode, trace) != trace) for (i = 1; i < (unsigned int) _dl_argc; ++i) { const ElfW(Sym) *ref = NULL; @@ -2083,7 +2053,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); } } #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED)) - if (version_info) + if (state.version_info) { /* Print more information. This means here, print information about the versions needed. */ @@ -2445,13 +2415,10 @@ print_missing_version (int errcode __attribute__ ((unused)), objname, errstring); } -/* Nonzero if any of the debugging options is enabled. */ -static int any_debug attribute_relro; - /* Process the string given as the parameter which explains which debugging options are enabled. */ static void -process_dl_debug (const char *dl_debug) +process_dl_debug (struct dl_main_state *state, const char *dl_debug) { /* When adding new entries make sure that the maximal length of a name is correctly handled in the LD_DEBUG_HELP code below. */ @@ -2508,7 +2475,7 @@ process_dl_debug (const char *dl_debug) && memcmp (dl_debug, debopts[cnt].name, len) == 0) { GLRO(dl_debug_mask) |= debopts[cnt].mask; - any_debug = 1; + state->any_debug = true; break; } @@ -2562,11 +2529,10 @@ extern char **_environ attribute_hidden; static void -process_envvars (enum mode *modep, struct audit_list *audit_list) +process_envvars (struct dl_main_state *state) { char **runp = _environ; char *envline; - enum mode mode = normal; char *debug_output = NULL; /* This is the default place for profiling data file. */ @@ -2598,25 +2564,25 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) /* Debugging of the dynamic linker? */ if (memcmp (envline, "DEBUG", 5) == 0) { - process_dl_debug (&envline[6]); + process_dl_debug (state, &envline[6]); break; } if (memcmp (envline, "AUDIT", 5) == 0) - audit_list_add_string (audit_list, &envline[6]); + audit_list_add_string (&state->audit_list, &envline[6]); break; case 7: /* Print information about versions. */ if (memcmp (envline, "VERBOSE", 7) == 0) { - version_info = envline[8] != '\0'; + state->version_info = envline[8] != '\0'; break; } /* List of objects to be preloaded. */ if (memcmp (envline, "PRELOAD", 7) == 0) { - preloadlist = &envline[8]; + state->preloadlist = &envline[8]; break; } @@ -2665,7 +2631,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) if (!__libc_enable_secure && memcmp (envline, "LIBRARY_PATH", 12) == 0) { - library_path = &envline[13]; + state->library_path = &envline[13]; break; } @@ -2707,7 +2673,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) /* The mode of the dynamic linker can be set. */ if (memcmp (envline, "TRACE_PRELINKING", 16) == 0) { - mode = trace; + state->mode = trace; GLRO(dl_verbose) = 1; GLRO(dl_debug_mask) |= DL_DEBUG_PRELINK; GLRO(dl_trace_prelink) = &envline[17]; @@ -2717,7 +2683,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) case 20: /* The mode of the dynamic linker can be set. */ if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0) - mode = trace; + state->mode = trace; break; /* We might have some extra environment variable to handle. This @@ -2730,9 +2696,6 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) } } - /* The caller wants this information. */ - *modep = mode; - /* Extra security for SUID binaries. Remove all dangerous environment variables. */ if (__builtin_expect (__libc_enable_secure, 0)) @@ -2761,13 +2724,13 @@ process_envvars (enum mode *modep, struct audit_list *audit_list) GLRO(dl_debug_mask) = 0; } - if (mode != normal) + if (state->mode != normal) _exit (5); } /* If we have to run the dynamic linker in debugging mode and the LD_DEBUG_OUTPUT environment variable is given, we write the debug messages to this file. */ - else if (any_debug && debug_output != NULL) + else if (state->any_debug && debug_output != NULL) { const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW; size_t name_len = strlen (debug_output);