Message ID | 37a8980cbc26bdd47c4e4c7b17e373c4f76b71e0.1601569371.git.fweimer@redhat.com |
---|---|
State | New |
Headers | show |
Series | glibc-hwcaps support | expand |
On 01/10/2020 13:31, Florian Weimer via Libc-alpha wrote: > Introduce struct dl_main_state and move it to <dl-main.h>. > > This avoids the need for putting state that is only needed during > startup into the ld.so data segment. LGTM, with some nits below. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > elf/dl-main.h | 95 +++++++++++++++++++++++++++++++ > elf/rtld.c | 155 +++++++++++++++++++------------------------------- > 2 files changed, 154 insertions(+), 96 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 > + <https://www.gnu.org/licenses/>. */ > + > +#ifndef _DL_MAIN > +#define _DL_MAIN > + > +#include <limits.h> > + > +/* 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 > + Ok. > +/* 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]; > +}; > + Ok. > +/* This is a list of all the modes the dynamic loader can be in. */ > +enum mode { normal, list, verify, trace }; > + With this enum now outside rtld.c maybe it would be better to use more explicit identifiers? > +/* 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; > +}; Ok. > + > +/* 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 */ Ok. > diff --git a/elf/rtld.c b/elf/rtld.c > index 9918fda05e..c1153cb627 100644 > --- a/elf/rtld.c > +++ b/elf/rtld.c > @@ -47,6 +47,7 @@ > #include <not-cancel.h> > #include <array_length.h> > #include <libc-early-init.h> > +#include <dl-main.h> > > #include <assert.h> > > @@ -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 > - Ok. > -/* 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]; > -}; > - Ok. > /* 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; > @@ -316,6 +281,18 @@ audit_list_count (struct audit_list *list) > return naudit; > } > Ok. > +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; > +} > + Ok. > #ifndef HAVE_INLINED_SYSCALLS > /* Set nonzero during loading and initialization of executable and > libraries, cleared before the executable's entry point runs. This > @@ -900,15 +877,6 @@ security_init (void) > > #include <setup-vdso.h> > > -/* 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; > - Ok. > /* 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. > @@ -1150,7 +1118,6 @@ 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; > @@ -1160,8 +1127,8 @@ 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; > Ok. > @@ -1176,7 +1143,7 @@ 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. */ Ok. > @@ -1210,7 +1177,7 @@ 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; > @@ -1219,7 +1186,7 @@ dl_main (const ElfW(Phdr) *phdr, > } > else if (! strcmp (_dl_argv[1], "--verify")) > { > - mode = verify; > + state.mode = verify; > > ++_dl_skip_args; > --_dl_argc; > @@ -1235,7 +1202,7 @@ 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; Ok. > @@ -1252,7 +1219,7 @@ 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; > @@ -1260,7 +1227,7 @@ 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; Ok. > @@ -1328,7 +1295,7 @@ 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; Use __glibc_likely here. > @@ -1357,7 +1324,7 @@ 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]) Ditto. > @@ -1604,7 +1571,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > _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 Ditto. > @@ -1634,7 +1601,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > > /* 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, Ok. > @@ -1699,14 +1666,14 @@ of this helper program; chances are you did not intend to run this program.\n\ > /* 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) > { > - size_t naudit = audit_list_count (&audit_list); > + size_t naudit = audit_list_count (&state.audit_list); > > /* Since we start using the auditing DSOs right away we need to > initialize the data structures now. */ > @@ -1719,7 +1686,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > security_init (); > need_security_init = false; > > - load_audit_modules (main_map, &audit_list); > + load_audit_modules (main_map, &state.audit_list); > > /* The count based on audit strings may overestimate the number > of audit modules that got loaded, but not underestimate. */ Ok. > @@ -1774,19 +1741,21 @@ of this helper program; chances are you did not intend to run this program.\n\ > 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); > } > Ok. > @@ -1893,7 +1862,8 @@ of this helper program; chances are you did not intend to run this program.\n\ > { > 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); > } > > @@ -1920,7 +1890,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > 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] Ok. > @@ -1953,8 +1923,8 @@ of this helper program; chances are you did not intend to run this program.\n\ > 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); > } > Ok. > @@ -1974,7 +1944,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > 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 Use __glibc_likely. > @@ -2076,7 +2046,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > (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; > @@ -2130,7 +2100,7 @@ of this helper program; chances are you did not intend to run this program.\n\ > } > } > #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. */ > @@ -2492,13 +2462,10 @@ 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. */ Ok. > @@ -2555,7 +2522,7 @@ 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; > } > > @@ -2609,11 +2576,10 @@ 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. */ > @@ -2645,25 +2611,25 @@ 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; > } > Ok. > @@ -2712,7 +2678,7 @@ 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; > } > > @@ -2754,7 +2720,7 @@ 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]; > @@ -2764,7 +2730,7 @@ 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 > @@ -2777,9 +2743,6 @@ 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)) > @@ -2808,13 +2771,13 @@ 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); > Ok.
* Adhemerval Zanella via Libc-alpha: >> +/* This is a list of all the modes the dynamic loader can be in. */ >> +enum mode { normal, list, verify, trace }; >> + > > With this enum now outside rtld.c maybe it would be better to use more > explicit identifiers? I pushed this with this suggested change as: commit 2bf9e641fd50ec34b04b70829679abf64fc0ed78 Author: Florian Weimer <fweimer@redhat.com> Date: Thu Oct 8 10:57:09 2020 +0200 elf: Extract command-line/environment variables state from rtld.c Introduce struct dl_main_state and move it to <dl-main.h>. Rename enum mode to enum rtld_mode and add the rtld_mode_ prefix to the enum constants. This avoids the need for putting state that is only needed during startup into the ld.so data segment. It also includes the __glibc_likely/__glibc_unlikely changes. Thanks, Florian
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 + <https://www.gnu.org/licenses/>. */ + +#ifndef _DL_MAIN +#define _DL_MAIN + +#include <limits.h> + +/* 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 9918fda05e..c1153cb627 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -47,6 +47,7 @@ #include <not-cancel.h> #include <array_length.h> #include <libc-early-init.h> +#include <dl-main.h> #include <assert.h> @@ -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; @@ -316,6 +281,18 @@ audit_list_count (struct audit_list *list) return naudit; } +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 @@ -900,15 +877,6 @@ security_init (void) #include <setup-vdso.h> -/* 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. @@ -1150,7 +1118,6 @@ 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; @@ -1160,8 +1127,8 @@ 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; @@ -1176,7 +1143,7 @@ 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. */ @@ -1210,7 +1177,7 @@ 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; @@ -1219,7 +1186,7 @@ dl_main (const ElfW(Phdr) *phdr, } else if (! strcmp (_dl_argv[1], "--verify")) { - mode = verify; + state.mode = verify; ++_dl_skip_args; --_dl_argc; @@ -1235,7 +1202,7 @@ 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; @@ -1252,7 +1219,7 @@ 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; @@ -1260,7 +1227,7 @@ 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; @@ -1328,7 +1295,7 @@ 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; @@ -1357,7 +1324,7 @@ 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]) @@ -1604,7 +1571,7 @@ of this helper program; chances are you did not intend to run this program.\n\ _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 @@ -1634,7 +1601,7 @@ of this helper program; chances are you did not intend to run this program.\n\ /* 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, @@ -1699,14 +1666,14 @@ of this helper program; chances are you did not intend to run this program.\n\ /* 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) { - size_t naudit = audit_list_count (&audit_list); + size_t naudit = audit_list_count (&state.audit_list); /* Since we start using the auditing DSOs right away we need to initialize the data structures now. */ @@ -1719,7 +1686,7 @@ of this helper program; chances are you did not intend to run this program.\n\ security_init (); need_security_init = false; - load_audit_modules (main_map, &audit_list); + load_audit_modules (main_map, &state.audit_list); /* The count based on audit strings may overestimate the number of audit modules that got loaded, but not underestimate. */ @@ -1774,19 +1741,21 @@ of this helper program; chances are you did not intend to run this program.\n\ 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); } @@ -1893,7 +1862,8 @@ of this helper program; chances are you did not intend to run this program.\n\ { 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); } @@ -1920,7 +1890,7 @@ of this helper program; chances are you did not intend to run this program.\n\ 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] @@ -1953,8 +1923,8 @@ of this helper program; chances are you did not intend to run this program.\n\ 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); } @@ -1974,7 +1944,7 @@ of this helper program; chances are you did not intend to run this program.\n\ 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 @@ -2076,7 +2046,7 @@ of this helper program; chances are you did not intend to run this program.\n\ (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; @@ -2130,7 +2100,7 @@ of this helper program; chances are you did not intend to run this program.\n\ } } #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. */ @@ -2492,13 +2462,10 @@ 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. */ @@ -2555,7 +2522,7 @@ 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; } @@ -2609,11 +2576,10 @@ 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. */ @@ -2645,25 +2611,25 @@ 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; } @@ -2712,7 +2678,7 @@ 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; } @@ -2754,7 +2720,7 @@ 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]; @@ -2764,7 +2730,7 @@ 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 @@ -2777,9 +2743,6 @@ 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)) @@ -2808,13 +2771,13 @@ 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);