diff options
| -rw-r--r-- | ChangeLog | 15 | ||||
| -rw-r--r-- | elf/rtld.c | 362 |
2 files changed, 215 insertions, 162 deletions
@@ -1,3 +1,18 @@ +2019-02-12 Florian Weimer <fweimer@redhat.com> + + [BZ #24122] + * elf/rtld.c (unload_audit_module): New function. + (report_audit_module_load_error): Likewise. + (load_audit_module): Likewise. Extracted from dl_main. Call + _dl_close if the laversion symbol cannot be found. Use early + returns for error handling. Add malloc error check. Check for a + zero return value from la_version. Remove spurious comment about + static TLS initialization. Remove useless casts. + (notify_audit_modules_of_loaded_object): New function. Extracted + from dl_main. + (load_audit_module): Likewise. + (dl_main): Call load_audit_modules. + 2019-02-12 Joseph Myers <joseph@codesourcery.com> * elf/dl-exception.c (_dl_exception_create_format): Add @@ -866,6 +866,205 @@ handle_preload_list (const char *preloadlist, struct link_map *main_map, return npreloads; } +/* Called if the audit DSO cannot be used: if it does not have the + appropriate interfaces, or it expects a more recent version library + version than what the dynamic linker provides. */ +static void +unload_audit_module (struct link_map *map, int original_tls_idx) +{ +#ifndef NDEBUG + Lmid_t ns = map->l_ns; +#endif + _dl_close (map); + + /* Make sure the namespace has been cleared entirely. */ + assert (GL(dl_ns)[ns]._ns_loaded == NULL); + assert (GL(dl_ns)[ns]._ns_nloaded == 0); + + GL(dl_tls_max_dtv_idx) = original_tls_idx; +} + +/* Called to print an error message if loading of an audit module + failed. */ +static void +report_audit_module_load_error (const char *name, const char *err_str, + bool malloced) +{ + _dl_error_printf ("\ +ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", + name, err_str); + if (malloced) + free ((char *) err_str); +} + +/* Load one audit module. */ +static void +load_audit_module (const char *name, struct audit_ifaces **last_audit) +{ + int original_tls_idx = GL(dl_tls_max_dtv_idx); + + struct dlmopen_args dlmargs; + dlmargs.fname = name; + dlmargs.map = NULL; + + const char *objname; + const char *err_str = NULL; + bool malloced; + _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit, &dlmargs); + if (__glibc_unlikely (err_str != NULL)) + { + report_audit_module_load_error (name, err_str, malloced); + return; + } + + struct lookup_args largs; + largs.name = "la_version"; + largs.map = dlmargs.map; + _dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs); + if (__glibc_likely (err_str != NULL)) + { + unload_audit_module (dlmargs.map, original_tls_idx); + report_audit_module_load_error (name, err_str, malloced); + return; + } + + unsigned int (*laversion) (unsigned int) = largs.result; + + /* A null symbol indicates that something is very wrong with the + loaded object because defined symbols are supposed to have a + valid, non-null address. */ + assert (laversion != NULL); + + unsigned int lav = laversion (LAV_CURRENT); + if (lav == 0) + { + /* Only print an error message if debugging because this can + happen deliberately. */ + if (GLRO(dl_debug_mask) & DL_DEBUG_FILES) + _dl_debug_printf ("\ +file=%s [%lu]; audit interface function la_version returned zero; ignored.\n", + dlmargs.map->l_name, dlmargs.map->l_ns); + unload_audit_module (dlmargs.map, original_tls_idx); + return; + } + + if (lav > LAV_CURRENT) + { + _dl_debug_printf ("\ +ERROR: audit interface '%s' requires version %d (maximum supported version %d); ignored.\n", + name, lav, LAV_CURRENT); + unload_audit_module (dlmargs.map, original_tls_idx); + return; + } + + enum { naudit_ifaces = 8 }; + union + { + struct audit_ifaces ifaces; + void (*fptr[naudit_ifaces]) (void); + } *newp = malloc (sizeof (*newp)); + if (newp == NULL) + _dl_fatal_printf ("Out of memory while loading audit modules\n"); + + /* Names of the auditing interfaces. All in one + long string. */ + static const char audit_iface_names[] = + "la_activity\0" + "la_objsearch\0" + "la_objopen\0" + "la_preinit\0" +#if __ELF_NATIVE_CLASS == 32 + "la_symbind32\0" +#elif __ELF_NATIVE_CLASS == 64 + "la_symbind64\0" +#else +# error "__ELF_NATIVE_CLASS must be defined" +#endif +#define STRING(s) __STRING (s) + "la_" STRING (ARCH_LA_PLTENTER) "\0" + "la_" STRING (ARCH_LA_PLTEXIT) "\0" + "la_objclose\0"; + unsigned int cnt = 0; + const char *cp = audit_iface_names; + do + { + largs.name = cp; + _dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs); + + /* Store the pointer. */ + if (err_str == NULL && largs.result != NULL) + { + newp->fptr[cnt] = largs.result; + + /* The dynamic linker link map is statically allocated, + initialize the data now. */ + GL(dl_rtld_map).l_audit[cnt].cookie = (intptr_t) &GL(dl_rtld_map); + } + else + newp->fptr[cnt] = NULL; + ++cnt; + + cp = rawmemchr (cp, '\0') + 1; + } + while (*cp != '\0'); + assert (cnt == naudit_ifaces); + + /* Now append the new auditing interface to the list. */ + newp->ifaces.next = NULL; + if (*last_audit == NULL) + *last_audit = GLRO(dl_audit) = &newp->ifaces; + else + *last_audit = (*last_audit)->next = &newp->ifaces; + ++GLRO(dl_naudit); + + /* Mark the DSO as being used for auditing. */ + dlmargs.map->l_auditing = 1; +} + +/* Notify the the audit modules that the object MAP has already been + loaded. */ +static void +notify_audit_modules_of_loaded_object (struct link_map *map) +{ + struct audit_ifaces *afct = GLRO(dl_audit); + for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) + { + if (afct->objopen != NULL) + { + map->l_audit[cnt].bindflags + = afct->objopen (map, LM_ID_BASE, &map->l_audit[cnt].cookie); + map->l_audit_any_plt |= map->l_audit[cnt].bindflags != 0; + } + + afct = afct->next; + } +} + +/* Load all audit modules. */ +static void +load_audit_modules (struct link_map *main_map) +{ + struct audit_ifaces *last_audit = NULL; + struct audit_list_iter al_iter; + audit_list_iter_init (&al_iter); + + while (true) + { + const char *name = audit_list_iter_next (&al_iter); + if (name == NULL) + break; + load_audit_module (name, &last_audit); + } + + /* Notify audit modules of the initially loaded modules (the main + program and the dynamic linker itself). */ + if (GLRO(dl_naudit) > 0) + { + notify_audit_modules_of_loaded_object (main_map); + notify_audit_modules_of_loaded_object (&GL(dl_rtld_map)); + } +} + static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum, @@ -1406,10 +1605,6 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); if (__glibc_unlikely (audit_list != NULL) || __glibc_unlikely (audit_list_string != NULL)) { - struct audit_ifaces *last_audit = NULL; - struct audit_list_iter al_iter; - audit_list_iter_init (&al_iter); - /* Since we start using the auditing DSOs right away we need to initialize the data structures now. */ tcbp = init_tls (); @@ -1421,164 +1616,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]); security_init (); need_security_init = false; - while (true) - { - const char *name = audit_list_iter_next (&al_iter); - if (name == NULL) - break; - - int tls_idx = GL(dl_tls_max_dtv_idx); - - /* Now it is time to determine the layout of the static TLS - block and allocate it for the initial thread. Note that we - always allocate the static block, we never defer it even if - no DF_STATIC_TLS bit is set. The reason is that we know - glibc will use the static model. */ - struct dlmopen_args dlmargs; - dlmargs.fname = name; - dlmargs.map = NULL; - - const char *objname; - const char *err_str = NULL; - bool malloced; - (void) _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit, - &dlmargs); - if (__glibc_unlikely (err_str != NULL)) - { - not_loaded: - _dl_error_printf ("\ -ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", - name, err_str); - if (malloced) - free ((char *) err_str); - } - else - { - struct lookup_args largs; - largs.name = "la_version"; - largs.map = dlmargs.map; - - /* Check whether the interface version matches. */ - (void) _dl_catch_error (&objname, &err_str, &malloced, - lookup_doit, &largs); - - unsigned int (*laversion) (unsigned int); - unsigned int lav; - if (err_str == NULL - && (laversion = largs.result) != NULL - && (lav = laversion (LAV_CURRENT)) > 0 - && lav <= LAV_CURRENT) - { - /* Allocate structure for the callback function pointers. - This call can never fail. */ - union - { - struct audit_ifaces ifaces; -#define naudit_ifaces 8 - void (*fptr[naudit_ifaces]) (void); - } *newp = malloc (sizeof (*newp)); - - /* Names of the auditing interfaces. All in one - long string. */ - static const char audit_iface_names[] = - "la_activity\0" - "la_objsearch\0" - "la_objopen\0" - "la_preinit\0" -#if __ELF_NATIVE_CLASS == 32 - "la_symbind32\0" -#elif __ELF_NATIVE_CLASS == 64 - "la_symbind64\0" -#else -# error "__ELF_NATIVE_CLASS must be defined" -#endif -#define STRING(s) __STRING (s) - "la_" STRING (ARCH_LA_PLTENTER) "\0" - "la_" STRING (ARCH_LA_PLTEXIT) "\0" - "la_objclose\0"; - unsigned int cnt = 0; - const char *cp = audit_iface_names; - do - { - largs.name = cp; - (void) _dl_catch_error (&objname, &err_str, &malloced, - lookup_doit, &largs); - - /* Store the pointer. */ - if (err_str == NULL && largs.result != NULL) - { - newp->fptr[cnt] = largs.result; - - /* The dynamic linker link map is statically - allocated, initialize the data now. */ - GL(dl_rtld_map).l_audit[cnt].cookie - = (intptr_t) &GL(dl_rtld_map); - } - else - newp->fptr[cnt] = NULL; - ++cnt; - - cp = (char *) rawmemchr (cp, '\0') + 1; - } - while (*cp != '\0'); - assert (cnt == naudit_ifaces); - - /* Now append the new auditing interface to the list. */ - newp->ifaces.next = NULL; - if (last_audit == NULL) - last_audit = GLRO(dl_audit) = &newp->ifaces; - else - last_audit = last_audit->next = &newp->ifaces; - ++GLRO(dl_naudit); - - /* Mark the DSO as being used for auditing. */ - dlmargs.map->l_auditing = 1; - } - else - { - /* We cannot use the DSO, it does not have the - appropriate interfaces or it expects something - more recent. */ -#ifndef NDEBUG - Lmid_t ns = dlmargs.map->l_ns; -#endif - _dl_close (dlmargs.map); - - /* Make sure the namespace has been cleared entirely. */ - assert (GL(dl_ns)[ns]._ns_loaded == NULL); - assert (GL(dl_ns)[ns]._ns_nloaded == 0); - - GL(dl_tls_max_dtv_idx) = tls_idx; - goto not_loaded; - } - } - } - - /* If we have any auditing modules, announce that we already - have two objects loaded. */ - if (__glibc_unlikely (GLRO(dl_naudit) > 0)) - { - struct link_map *ls[2] = { main_map, &GL(dl_rtld_map) }; - - for (unsigned int outer = 0; outer < 2; ++outer) - { - struct audit_ifaces *afct = GLRO(dl_audit); - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - if (afct->objopen != NULL) - { - ls[outer]->l_audit[cnt].bindflags - = afct->objopen (ls[outer], LM_ID_BASE, - &ls[outer]->l_audit[cnt].cookie); - - ls[outer]->l_audit_any_plt - |= ls[outer]->l_audit[cnt].bindflags != 0; - } - - afct = afct->next; - } - } - } + load_audit_modules (main_map); } /* Keep track of the currently loaded modules to count how many |