Date: Thu, 02 Apr 2026 02:17:06 +0000 From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 1e4debcf698f - stable/15 - rtld: properly handle update of several vars in rtld_set_var() Message-ID: <69cdd1a2.3413a.6f854c4@gitrepo.freebsd.org>
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The branch stable/15 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=1e4debcf698f364fe857f7cbda53272e4fafa161 commit 1e4debcf698f364fe857f7cbda53272e4fafa161 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2026-03-24 01:43:23 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2026-04-02 02:13:50 +0000 rtld: properly handle update of several vars in rtld_set_var() (cherry picked from commit b9f046d941c4dbd0e4fc634827ada6e7cf6a6bcf) --- libexec/rtld-elf/rtld.c | 188 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 152 insertions(+), 36 deletions(-) diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c index 8ac897508870..0cdb09f10121 100644 --- a/libexec/rtld-elf/rtld.c +++ b/libexec/rtld-elf/rtld.c @@ -187,6 +187,10 @@ static char *origin_subst_one(Obj_Entry *, char *, const char *, const char *, static char *origin_subst(Obj_Entry *, const char *); static bool obj_resolve_origin(Obj_Entry *obj); static void preinit_main(void); +static void rtld_recalc_bind_not(const char *); +static void rtld_recalc_dangerous_ld_env(void); +static void rtld_recalc_debug(const char *); +static void rtld_recalc_path_rpath(const char *); static int rtld_verify_versions(const Objlist *); static int rtld_verify_object_versions(Obj_Entry *); static void object_add_name(Obj_Entry *, const char *); @@ -198,6 +202,17 @@ static uint32_t gnu_hash(const char *); static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, const unsigned long); +struct ld_env_var_desc; +static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd); +static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd); +static void rtld_set_var_debug(struct ld_env_var_desc *lvd); +static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd); +static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd); +static void rtld_set_var_library_path(struct ld_env_var_desc *lvd); +static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd); +static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd); +static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd); + void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; void _r_debug_postinit(struct link_map *) __noinline __exported; @@ -215,7 +230,6 @@ static bool dangerous_ld_env; /* True if environment variables have been used to affect the libraries loaded */ bool ld_bind_not; /* Disable PLT update */ static const char *ld_bind_now; /* Environment variable for immediate binding */ -static const char *ld_debug; /* Environment variable for debugging */ static bool ld_dynamic_weak = true; /* True if non-weak definition overrides weak definition */ static const char *ld_library_path; /* Environment variable for search path */ @@ -367,26 +381,35 @@ struct ld_env_var_desc { const char *val; const bool unsecure : 1; const bool can_update : 1; - const bool debug : 1; bool owned : 1; + void (*const on_update)(struct ld_env_var_desc *); }; #define LD_ENV_DESC(var, unsec, ...) \ [LD_##var] = { .n = #var, .unsecure = unsec, __VA_ARGS__ } static struct ld_env_var_desc ld_env_vars[] = { - LD_ENV_DESC(BIND_NOW, false), + LD_ENV_DESC(BIND_NOW, false, .can_update = true, + .on_update = rtld_set_var_bind_now), LD_ENV_DESC(PRELOAD, true), LD_ENV_DESC(LIBMAP, true), - LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true), - LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true), - LD_ENV_DESC(LIBMAP_DISABLE, true), - LD_ENV_DESC(BIND_NOT, true), - LD_ENV_DESC(DEBUG, true, .can_update = true, .debug = true), + LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true, + .on_update = rtld_set_var_library_path), + LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true, + .on_update = rtld_set_var_library_path_fds), + LD_ENV_DESC(LIBMAP_DISABLE, true, .can_update = true, + .on_update = rtld_set_var_libmap_disable), + LD_ENV_DESC(BIND_NOT, true, .can_update = true, + .on_update = rtld_set_var_bind_not), + LD_ENV_DESC(DEBUG, true, .can_update = true, + .on_update = rtld_set_var_debug), LD_ENV_DESC(ELF_HINTS_PATH, true), - LD_ENV_DESC(LOADFLTR, true), - LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true), + LD_ENV_DESC(LOADFLTR, true, .can_update = true, + .on_update = rtld_set_var_loadfltr), + LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true, + .on_update = rtld_set_var_library_path_rpath), LD_ENV_DESC(PRELOAD_FDS, true), - LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true), + LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true, + .on_update = rtld_set_var_dynamic_weak), LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), LD_ENV_DESC(UTRACE, false, .can_update = true), LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true), @@ -515,7 +538,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) struct stat st; Elf_Addr *argcp; char **argv, **env, **envp, *kexecpath; - const char *argv0, *binpath, *library_path_rpath, *static_tls_extra; + const char *argv0, *binpath, *static_tls_extra; struct ld_env_var_desc *lvd; caddr_t imgentry; char buf[MAXPATHLEN]; @@ -720,9 +743,8 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) } } - ld_debug = ld_get_env_var(LD_DEBUG); - if (ld_bind_now == NULL) - ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; + rtld_recalc_debug(ld_get_env_var(LD_DEBUG)); + rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT)); ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; libmap_override = ld_get_env_var(LD_LIBMAP); @@ -732,31 +754,18 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; - library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); - if (library_path_rpath != NULL) { - if (library_path_rpath[0] == 'y' || - library_path_rpath[0] == 'Y' || - library_path_rpath[0] == '1') - ld_library_path_rpath = true; - else - ld_library_path_rpath = false; - } + rtld_recalc_path_rpath(ld_get_env_var(LD_LIBRARY_PATH_RPATH)); static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { sz = parse_integer(static_tls_extra); if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) ld_static_tls_extra = sz; } - dangerous_ld_env = libmap_disable || libmap_override != NULL || - ld_library_path != NULL || ld_preload != NULL || - ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || - static_tls_extra != NULL; + rtld_recalc_dangerous_ld_env(); ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); ld_utrace = ld_get_env_var(LD_UTRACE); set_ld_elf_hints_path(); - if (ld_debug != NULL && *ld_debug != '\0') - debug = 1; dbg("%s is initialized, base address = %p", __progname, (caddr_t)aux_info[AT_BASE]->a_un.a_ptr); dbg("RTLD dynamic = %p", obj_rtld.dynamic); @@ -6615,18 +6624,121 @@ rtld_get_var(const char *name) return (NULL); } +static void +rtld_recalc_dangerous_ld_env(void) +{ + /* + * Never reset dangerous_ld_env back to false if rtld was ever + * contaminated with it set to true. + */ + dangerous_ld_env |= libmap_disable || libmap_override != NULL || + ld_library_path != NULL || ld_preload != NULL || + ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || + ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL; +} + +static void +rtld_recalc_debug(const char *ld_debug) +{ + if (ld_debug != NULL && *ld_debug != '\0') + debug = 1; +} + +static void +rtld_set_var_debug(struct ld_env_var_desc *lvd) +{ + rtld_recalc_debug(lvd->val); +} + +static void +rtld_set_var_library_path(struct ld_env_var_desc *lvd) +{ + ld_library_path = lvd->val; +} + +static void +rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd) +{ + ld_library_dirs = lvd->val; +} + +static void +rtld_recalc_path_rpath(const char *library_path_rpath) +{ + if (library_path_rpath != NULL) { + if (library_path_rpath[0] == 'y' || + library_path_rpath[0] == 'Y' || + library_path_rpath[0] == '1') + ld_library_path_rpath = true; + else + ld_library_path_rpath = false; + } else { + ld_library_path_rpath = false; + } +} + +static void +rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd) +{ + rtld_recalc_path_rpath(lvd->val); +} + +static void +rtld_recalc_bind_not(const char *bind_not_val) +{ + if (ld_bind_now == NULL) + ld_bind_not = bind_not_val != NULL; +} + +static void +rtld_set_var_bind_now(struct ld_env_var_desc *lvd) +{ + ld_bind_now = lvd->val; + rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT)); +} + +static void +rtld_set_var_bind_not(struct ld_env_var_desc *lvd) +{ + rtld_recalc_bind_not(lvd->val); +} + +static void +rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd) +{ + ld_dynamic_weak = lvd->val == NULL; +} + +static void +rtld_set_var_loadfltr(struct ld_env_var_desc *lvd) +{ + ld_loadfltr = lvd->val != NULL; +} + +static void +rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd) +{ + libmap_disable = lvd->val != NULL; +} + int rtld_set_var(const char *name, const char *val) { + RtldLockState lockstate; struct ld_env_var_desc *lvd; u_int i; + int error; + error = ENOENT; + wlock_acquire(rtld_bind_lock, &lockstate); for (i = 0; i < nitems(ld_env_vars); i++) { lvd = &ld_env_vars[i]; if (strcmp(lvd->n, name) != 0) continue; - if (!lvd->can_update || (lvd->unsecure && !trust)) - return (EPERM); + if (!lvd->can_update || (lvd->unsecure && !trust)) { + error = EPERM; + break; + } if (lvd->owned) free(__DECONST(char *, lvd->val)); if (val != NULL) @@ -6634,11 +6746,15 @@ rtld_set_var(const char *name, const char *val) else lvd->val = NULL; lvd->owned = true; - if (lvd->debug) - debug = lvd->val != NULL && *lvd->val != '\0'; - return (0); + if (lvd->on_update != NULL) + lvd->on_update(lvd); + error = 0; + break; } - return (ENOENT); + if (error == 0) + rtld_recalc_dangerous_ld_env(); + lock_release(rtld_bind_lock, &lockstate); + return (error); } /*home | help
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