/* * SPDX-License-Identifier: ISC * * Copyright (c) 2000-2005, 2007-2023 * Todd C. Miller * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Sponsored in part by the Defense Advanced Research Projects * Agency (DARPA) and Air Force Research Laboratory, Air Force * Materiel Command, USAF, under agreement number F39502-99-1-0512. */ /* * This is an open source non-commercial project. Dear PVS-Studio, please check it. * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com */ #include #include #include #include #include #if defined(HAVE_STDINT_H) # include #elif defined(HAVE_INTTYPES_H) # include #endif #ifdef HAVE_LOGIN_CAP_H # include # ifndef LOGIN_SETENV # define LOGIN_SETENV 0 # endif #endif /* HAVE_LOGIN_CAP_H */ #include #include #include #include #include /* * Flags used in rebuild_env() */ #undef DID_TERM #define DID_TERM 0x00000001 #undef DID_PATH #define DID_PATH 0x00000002 #undef DID_HOME #define DID_HOME 0x00000004 #undef DID_SHELL #define DID_SHELL 0x00000008 #undef DID_LOGNAME #define DID_LOGNAME 0x00000010 #undef DID_USER #define DID_USER 0x00000020 #undef DID_LOGIN #define DID_LOGIN 0x00000040 #undef DID_MAIL #define DID_MAIL 0x00000080 #undef DID_MAX #define DID_MAX 0x0000ffff #undef KEPT_TERM #define KEPT_TERM 0x00010000 #undef KEPT_PATH #define KEPT_PATH 0x00020000 #undef KEPT_HOME #define KEPT_HOME 0x00040000 #undef KEPT_SHELL #define KEPT_SHELL 0x00080000 #undef KEPT_LOGNAME #define KEPT_LOGNAME 0x00100000 #undef KEPT_USER #define KEPT_USER 0x00200000 #undef KEPT_LOGIN #define KEPT_LOGIN 0x00400000 #undef KEPT_MAIL #define KEPT_MAIL 0x00800000 #undef KEPT_MAX #define KEPT_MAX 0xffff0000 /* * AIX sets the LOGIN environment variable too. */ #ifdef _AIX # define KEPT_USER_VARIABLES (KEPT_LOGIN|KEPT_LOGNAME|KEPT_USER) #else # define KEPT_USER_VARIABLES (KEPT_LOGNAME|KEPT_USER) #endif /* * Functions to open, close and parse an environment file, either * a system file such as /etc/environment or one specified in sudoers. */ struct sudoers_env_file { void * (*open)(const char *); void (*close)(void *); char * (*next)(void *, int *); }; /* * State for a local environment file. */ struct env_file_local { FILE *fp; char *line; size_t linesize; }; struct environment { char **envp; /* pointer to the new environment */ char **old_envp; /* pointer the old environment we allocated */ size_t env_size; /* size of new_environ in char **'s */ size_t env_len; /* number of slots used, not counting NULL */ }; /* * Copy of the sudo-managed environment. */ static struct environment env; /* * Default table of "bad" variables to remove from the environment. * XXX - how to omit TERMCAP if it starts with '/'? */ static const char *initial_badenv_table[] = { "IFS", "CDPATH", "LOCALDOMAIN", "RES_OPTIONS", "HOSTALIASES", "NLSPATH", "PATH_LOCALE", "LD_*", "_RLD*", #ifdef __hpux "SHLIB_PATH", #endif /* __hpux */ #ifdef _AIX "LDR_*", "LIBPATH", "AUTHSTATE", #endif #ifdef __APPLE__ "DYLD_*", #endif #ifdef HAVE_KERB5 "KRB5_CONFIG*", "KRB5_KTNAME", #endif /* HAVE_KERB5 */ #ifdef HAVE_SECURID "VAR_ACE", "USR_ACE", "DLC_ACE", #endif /* HAVE_SECURID */ "TERMINFO", /* terminfo, exclusive path to terminfo files */ "TERMINFO_DIRS", /* terminfo, path(s) to terminfo files */ "TERMPATH", /* termcap, path(s) to termcap files */ "TERMCAP", /* XXX - only if it starts with '/' */ "ENV", /* ksh, file to source before script runs */ "BASH_ENV", /* bash, file to source before script runs */ "PS4", /* bash, prefix for lines in xtrace mode */ "GLOBIGNORE", /* bash, globbing patterns to ignore */ "BASHOPTS", /* bash, initial "shopt -s" options */ "SHELLOPTS", /* bash, initial "set -o" options */ "JAVA_TOOL_OPTIONS", /* java, extra command line options */ "PERLIO_DEBUG", /* perl, debugging output file */ "PERLLIB", /* perl, search path for modules/includes */ "PERL5LIB", /* perl 5, search path for modules/includes */ "PERL5OPT", /* perl 5, extra command line options */ "PERL5DB", /* perl 5, command used to load debugger */ "FPATH", /* ksh, search path for functions */ "NULLCMD", /* zsh, command for null file redirection */ "READNULLCMD", /* zsh, command for null file redirection */ "ZDOTDIR", /* zsh, search path for dot files */ "TMPPREFIX", /* zsh, prefix for temporary files */ "PYTHONHOME", /* python, module search path */ "PYTHONPATH", /* python, search path */ "PYTHONINSPECT", /* python, allow inspection */ "PYTHONUSERBASE", /* python, per user site-packages directory */ "RUBYLIB", /* ruby, library load path */ "RUBYOPT", /* ruby, extra command line options */ "*=()*", /* bash functions */ NULL }; /* * Default table of variables to check for '%' and '/' characters. */ static const char *initial_checkenv_table[] = { "COLORTERM", "LANG", "LANGUAGE", "LC_*", "LINGUAS", "TERM", "TZ", NULL }; /* * Default table of variables to preserve in the environment. */ static const char *initial_keepenv_table[] = { "COLORS", "DISPLAY", "HOSTNAME", "KRB5CCNAME", "LS_COLORS", "PATH", "PS1", "PS2", "XAUTHORITY", "XAUTHORIZATION", "XDG_CURRENT_DESKTOP", NULL }; /* * Free our copy (or copies) of the environment. * This function is only safe to call after the command has executed. */ void env_free(void) { sudoers_gc_remove(GC_PTR, env.envp); free(env.envp); sudoers_gc_remove(GC_PTR, env.old_envp); free(env.old_envp); memset(&env, 0, sizeof(env)); } /* * Initialize env based on envp. */ bool env_init(char * const envp[]) { char * const *ep; size_t len; debug_decl(env_init, SUDOERS_DEBUG_ENV); if (envp == NULL) { /* Free the old envp we allocated, if any. */ sudoers_gc_remove(GC_PTR, env.old_envp); free(env.old_envp); /* * Reset to initial state but keep a pointer to what we allocated * since it will be passed to execve(2). */ env.old_envp = env.envp; env.envp = NULL; env.env_size = 0; env.env_len = 0; } else { /* Make private copy of envp. */ for (ep = envp; *ep != NULL; ep++) continue; len = (size_t)(ep - envp); env.env_len = len; env.env_size = len + 1 + 128; env.envp = reallocarray(NULL, env.env_size, sizeof(char *)); if (env.envp == NULL) { env.env_size = 0; env.env_len = 0; sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory")); debug_return_bool(false); } sudoers_gc_add(GC_PTR, env.envp); #ifdef ENV_DEBUG memset(env.envp, 0, env.env_size * sizeof(char *)); #endif memcpy(env.envp, envp, len * sizeof(char *)); env.envp[len] = NULL; /* Free the old envp we allocated, if any. */ sudoers_gc_remove(GC_PTR, env.old_envp); free(env.old_envp); env.old_envp = NULL; } debug_return_bool(true); } /* * Getter for private copy of the environment. */ char ** env_get(void) { return env.envp; } /* * Swap the old and new copies of the environment. */ bool env_swap_old(void) { char **old_envp; if (env.old_envp == NULL) return false; old_envp = env.old_envp; env.old_envp = env.envp; env.envp = old_envp; return true; } /* * Similar to putenv(3) but operates on sudo's private copy of the * environment (not environ) and it always overwrites. The dupcheck param * determines whether we need to verify that the variable is not already set. * Will only overwrite an existing variable if overwrite is set. * Does not include warnings or debugging to avoid recursive calls. */ int sudo_putenv_nodebug(char *str, bool dupcheck, bool overwrite) { char **ep; const char *equal; bool found = false; /* Some putenv(3) implementations check for NULL. */ if (str == NULL) { errno = EINVAL; return -1; } /* The string must contain a '=' char but not start with one. */ equal = strchr(str, '='); if (equal == NULL || equal == str) { errno = EINVAL; return -1; } /* Make sure there is room for the new entry plus a NULL. */ if (env.env_size > 2 && env.env_len > env.env_size - 2) { char **nenvp; size_t nsize; if (env.env_size > SIZE_MAX - 128) { sudo_warnx_nodebug(U_("internal error, %s overflow"), "sudo_putenv_nodebug"); errno = EOVERFLOW; return -1; } nsize = env.env_size + 128; if (nsize > SIZE_MAX / sizeof(char *)) { sudo_warnx_nodebug(U_("internal error, %s overflow"), "sudo_putenv_nodebug"); errno = EOVERFLOW; return -1; } sudoers_gc_remove(GC_PTR, env.envp); nenvp = reallocarray(env.envp, nsize, sizeof(char *)); if (nenvp == NULL) { sudoers_gc_add(GC_PTR, env.envp); return -1; } sudoers_gc_add(GC_PTR, nenvp); env.envp = nenvp; env.env_size = nsize; #ifdef ENV_DEBUG memset(env.envp + env.env_len, 0, (env.env_size - env.env_len) * sizeof(char *)); #endif } #ifdef ENV_DEBUG if (env.envp[env.env_len] != NULL) { errno = EINVAL; return -1; } #endif if (dupcheck) { size_t len = (size_t)(equal - str) + 1; for (ep = env.envp; *ep != NULL; ep++) { if (strncmp(str, *ep, len) == 0) { if (overwrite) *ep = str; found = true; break; } } /* Prune out extra instances of the variable we just overwrote. */ if (found && overwrite) { while (*++ep != NULL) { if (strncmp(str, *ep, len) == 0) { char **cur = ep; while ((*cur = *(cur + 1)) != NULL) cur++; ep--; } } env.env_len = (size_t)(ep - env.envp); } } if (!found) { ep = env.envp + env.env_len; env.env_len++; *ep++ = str; *ep = NULL; } return 0; } /* * Similar to putenv(3) but operates on sudo's private copy of the * environment (not environ) and it always overwrites. The dupcheck param * determines whether we need to verify that the variable is not already set. * Will only overwrite an existing variable if overwrite is set. */ static int sudo_putenv(char *str, bool dupcheck, bool overwrite) { int ret; debug_decl(sudo_putenv, SUDOERS_DEBUG_ENV); sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_putenv: %s", str); ret = sudo_putenv_nodebug(str, dupcheck, overwrite); if (ret == -1) { #ifdef ENV_DEBUG if (env.envp[env.env_len] != NULL) { sudo_warnx("%s", U_("sudo_putenv: corrupted envp, length mismatch")); } #endif } debug_return_int(ret); } /* * Similar to setenv(3) but operates on a private copy of the environment. * The dupcheck param determines whether we need to verify that the variable * is not already set. */ static int sudo_setenv2(const char *var, const char *val, bool dupcheck, bool overwrite) { char *estring; size_t esize; int ret = -1; debug_decl(sudo_setenv2, SUDOERS_DEBUG_ENV); esize = strlen(var) + 1 + strlen(val) + 1; if ((estring = malloc(esize)) == NULL) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); debug_return_int(-1); } /* Build environment string and insert it. */ if (strlcpy(estring, var, esize) >= esize || strlcat(estring, "=", esize) >= esize || strlcat(estring, val, esize) >= esize) { sudo_warnx(U_("internal error, %s overflow"), __func__); errno = EOVERFLOW; } else { ret = sudo_putenv(estring, dupcheck, overwrite); } if (ret == -1) free(estring); else sudoers_gc_add(GC_PTR, estring); debug_return_int(ret); } /* * Similar to setenv(3) but operates on a private copy of the environment. */ int sudo_setenv(const char *var, const char *val, int overwrite) { return sudo_setenv2(var, val, true, (bool)overwrite); } /* * Similar to unsetenv(3) but operates on a private copy of the environment. * Does not include warnings or debugging to avoid recursive calls. */ int sudo_unsetenv_nodebug(const char *var) { char **ep = env.envp; size_t len; if (ep == NULL || var == NULL || *var == '\0' || strchr(var, '=') != NULL) { errno = EINVAL; return -1; } len = strlen(var); while (*ep != NULL) { if (strncmp(var, *ep, len) == 0 && (*ep)[len] == '=') { /* Found it; shift remainder + NULL over by one. */ char **cur = ep; while ((*cur = *(cur + 1)) != NULL) cur++; env.env_len--; /* Keep going, could be multiple instances of the var. */ } else { ep++; } } return 0; } /* * Similar to unsetenv(3) but operates on a private copy of the environment. */ int sudo_unsetenv(const char *name) { int ret; debug_decl(sudo_unsetenv, SUDOERS_DEBUG_ENV); sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_unsetenv: %s", name); ret = sudo_unsetenv_nodebug(name); debug_return_int(ret); } /* * Similar to getenv(3) but operates on a private copy of the environment. * Does not include warnings or debugging to avoid recursive calls. */ char * sudo_getenv_nodebug(const char *name) { char **ep, *val = NULL; size_t namelen = 0; if (env.env_len != 0) { /* For BSD compatibility, treat '=' in name like end of string. */ while (name[namelen] != '\0' && name[namelen] != '=') namelen++; for (ep = env.envp; *ep != NULL; ep++) { if (strncmp(*ep, name, namelen) == 0 && (*ep)[namelen] == '=') { val = *ep + namelen + 1; break; } } } return val; } /* * Similar to getenv(3) but operates on a private copy of the environment. */ char * sudo_getenv(const char *name) { char *val; debug_decl(sudo_getenv, SUDOERS_DEBUG_ENV); sudo_debug_printf(SUDO_DEBUG_INFO, "sudo_getenv: %s", name); val = sudo_getenv_nodebug(name); debug_return_str(val); } /* * Check for var against patterns in the specified environment list. * Returns true if the variable was found, else false. */ static bool matches_env_list(const char *var, struct list_members *list, bool *full_match) { struct list_member *cur; bool is_logname = false; debug_decl(matches_env_list, SUDOERS_DEBUG_ENV); switch (*var) { case 'L': if (strncmp(var, "LOGNAME=", 8) == 0) is_logname = true; #ifdef _AIX else if (strncmp(var, "LOGIN=", 6) == 0) is_logname = true; #endif break; case 'U': if (strncmp(var, "USER=", 5) == 0) is_logname = true; break; } if (is_logname) { /* * We treat LOGIN, LOGNAME and USER specially. * If one is preserved/deleted we want to preserve/delete them all. */ SLIST_FOREACH(cur, list, entries) { if (matches_env_pattern(cur->value, "LOGNAME", full_match) || #ifdef _AIX matches_env_pattern(cur->value, "LOGIN", full_match) || #endif matches_env_pattern(cur->value, "USER", full_match)) debug_return_bool(true); } } else { SLIST_FOREACH(cur, list, entries) { if (matches_env_pattern(cur->value, var, full_match)) debug_return_bool(true); } } debug_return_bool(false); } /* * Check the env_delete blocklist. * Returns true if the variable was found, else false. */ static bool matches_env_delete(const char *var) { bool full_match; /* unused */ debug_decl(matches_env_delete, SUDOERS_DEBUG_ENV); /* Skip anything listed in env_delete. */ debug_return_bool(matches_env_list(var, &def_env_delete, &full_match)); } /* * Verify the TZ environment variable is safe. * On many systems it is possible to set this to a pathname. */ static bool tz_is_safe(const char *tzval) { const char *cp; char lastch; debug_decl(tz_is_safe, SUDOERS_DEBUG_ENV); /* tzcode treats a value beginning with a ':' as a path. */ if (tzval[0] == ':') tzval++; /* Reject fully-qualified TZ that doesn't being with the zoneinfo dir. */ if (tzval[0] == '/') { #ifdef _PATH_ZONEINFO if (strncmp(tzval, _PATH_ZONEINFO, sizeof(_PATH_ZONEINFO) - 1) != 0 || tzval[sizeof(_PATH_ZONEINFO) - 1] != '/') debug_return_bool(false); #else /* Assume the worst. */ debug_return_bool(false); #endif } /* * Make sure TZ only contains printable non-space characters * and does not contain a '..' path element. */ lastch = '/'; for (cp = tzval; *cp != '\0'; cp++) { if (isspace((unsigned char)*cp) || !isprint((unsigned char)*cp)) debug_return_bool(false); if (lastch == '/' && cp[0] == '.' && cp[1] == '.' && (cp[2] == '/' || cp[2] == '\0')) debug_return_bool(false); lastch = *cp; } /* Reject extra long TZ values (even if not a path). */ if ((size_t)(cp - tzval) >= PATH_MAX) debug_return_bool(false); debug_return_bool(true); } /* * Apply the env_check list. * Returns true if the variable is allowed, false if denied * or -1 if no match. */ static int matches_env_check(const char *var, bool *full_match) { int keepit = -1; debug_decl(matches_env_check, SUDOERS_DEBUG_ENV); /* Skip anything listed in env_check that includes '/' or '%'. */ if (matches_env_list(var, &def_env_check, full_match)) { if (strncmp(var, "TZ=", 3) == 0) { /* Special case for TZ */ keepit = tz_is_safe(var + 3); } else { const char *val = strchr(var, '='); if (val != NULL) keepit = !strpbrk(val + 1, "/%"); } } debug_return_int(keepit); } /* * Check the env_keep list. * Returns true if the variable is allowed else false. */ static bool matches_env_keep(const struct sudoers_context *ctx, const char *var, bool *full_match) { bool keepit = false; debug_decl(matches_env_keep, SUDOERS_DEBUG_ENV); /* Preserve SHELL variable for "sudo -s". */ if (ISSET(ctx->mode, MODE_SHELL) && strncmp(var, "SHELL=", 6) == 0) { keepit = true; } else if (matches_env_list(var, &def_env_keep, full_match)) { keepit = true; } debug_return_bool(keepit); } /* * Look up var in the env_delete and env_check. * Returns true if we should delete the variable, else false. */ static bool env_should_delete(const char *var) { int delete_it; bool full_match = false; debug_decl(env_should_delete, SUDOERS_DEBUG_ENV); delete_it = matches_env_delete(var); if (!delete_it) delete_it = matches_env_check(var, &full_match) == false; sudo_debug_printf(SUDO_DEBUG_INFO, "delete %s: %s", var, delete_it ? "YES" : "NO"); debug_return_bool(delete_it); } /* * Lookup var in the env_check and env_keep lists. * Returns true if the variable is allowed else false. */ static bool env_should_keep(const struct sudoers_context *ctx, const char *var) { int keepit; bool full_match = false; const char *cp; debug_decl(env_should_keep, SUDOERS_DEBUG_ENV); keepit = matches_env_check(var, &full_match); if (keepit == -1) keepit = matches_env_keep(ctx, var, &full_match); /* Skip bash functions unless we matched on the value as well as name. */ if (keepit && !full_match) { if ((cp = strchr(var, '=')) != NULL) { if (strncmp(cp, "=() ", 4) == 0) keepit = false; } } sudo_debug_printf(SUDO_DEBUG_INFO, "keep %s: %s", var, keepit == true ? "YES" : "NO"); debug_return_bool(keepit == true); } #ifdef HAVE_PAM /* * Merge another environment with our private copy. * Only overwrite an existing variable if it is not * being preserved from the user's environment. * Returns true on success or false on failure. */ bool env_merge(const struct sudoers_context *ctx, char * const envp[]) { char * const *ep; bool ret = true; debug_decl(env_merge, SUDOERS_DEBUG_ENV); for (ep = envp; *ep != NULL; ep++) { /* XXX - avoid checking value here, should only check name */ bool overwrite = def_env_reset ? !env_should_keep(ctx, *ep) : env_should_delete(*ep); if (sudo_putenv(*ep, true, overwrite) == -1) { /* XXX cannot undo on failure */ ret = false; break; } } debug_return_bool(ret); } #endif /* HAVE_PAM */ static void env_update_didvar(const char *ep, unsigned int *didvar) { switch (*ep) { case 'H': if (strncmp(ep, "HOME=", 5) == 0) SET(*didvar, DID_HOME); break; case 'L': #ifdef _AIX if (strncmp(ep, "LOGIN=", 8) == 0) SET(*didvar, DID_LOGIN); #endif if (strncmp(ep, "LOGNAME=", 8) == 0) SET(*didvar, DID_LOGNAME); break; case 'M': if (strncmp(ep, "MAIL=", 5) == 0) SET(*didvar, DID_MAIL); break; case 'P': if (strncmp(ep, "PATH=", 5) == 0) SET(*didvar, DID_PATH); break; case 'S': if (strncmp(ep, "SHELL=", 6) == 0) SET(*didvar, DID_SHELL); break; case 'T': if (strncmp(ep, "TERM=", 5) == 0) SET(*didvar, DID_TERM); break; case 'U': if (strncmp(ep, "USER=", 5) == 0) SET(*didvar, DID_USER); break; } } #define CHECK_PUTENV(a, b, c) do { \ if (sudo_putenv((char *)(a), (b), (c)) == -1) { \ goto bad; \ } \ } while (0) #define CHECK_SETENV2(a, b, c, d) do { \ if (sudo_setenv2((char *)(a), (b), (c), (d)) == -1) { \ goto bad; \ } \ } while (0) /* * Build a new environment and either clear potentially dangerous * variables from the old one or start with a clean slate. * Also adds sudo-specific variables (SUDO_*). * Returns true on success or false on failure. */ bool rebuild_env(const struct sudoers_context *ctx) { char **ep, *cp, *ps1; char idbuf[STRLEN_MAX_UNSIGNED(uid_t) + 1]; unsigned int didvar; bool reset_home = false; int len; debug_decl(rebuild_env, SUDOERS_DEBUG_ENV); /* * Either clean out the environment or reset to a safe default. */ ps1 = NULL; didvar = 0; env.env_len = 0; env.env_size = 128; sudoers_gc_remove(GC_PTR, env.old_envp); free(env.old_envp); env.old_envp = env.envp; env.envp = reallocarray(NULL, env.env_size, sizeof(char *)); if (env.envp == NULL) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); env.env_size = 0; goto bad; } sudoers_gc_add(GC_PTR, env.envp); #ifdef ENV_DEBUG memset(env.envp, 0, env.env_size * sizeof(char *)); #else env.envp[0] = NULL; #endif /* Reset HOME based on target user if configured to. */ if (ISSET(ctx->mode, MODE_RUN)) { if (def_always_set_home || ISSET(ctx->mode, MODE_RESET_HOME | MODE_LOGIN_SHELL) || (ISSET(ctx->mode, MODE_SHELL) && def_set_home)) reset_home = true; } if (def_env_reset || ISSET(ctx->mode, MODE_LOGIN_SHELL)) { /* * If starting with a fresh environment, initialize it based on * /etc/environment or login.conf. For "sudo -i" we want those * variables to override the invoking user's environment, so we * defer reading them until later. */ if (!ISSET(ctx->mode, MODE_LOGIN_SHELL)) { #ifdef HAVE_LOGIN_CAP_H /* Insert login class environment variables. */ if (ctx->runas.class) { login_cap_t *lc = login_getclass(ctx->runas.class); if (lc != NULL) { setusercontext(lc, ctx->runas.pw, ctx->runas.pw->pw_uid, LOGIN_SETPATH|LOGIN_SETENV); login_close(lc); } } #endif /* HAVE_LOGIN_CAP_H */ #ifdef _PATH_ENVIRONMENT /* Insert system-wide environment variables. */ if (!read_env_file(ctx, _PATH_ENVIRONMENT, true, false)) sudo_warn("%s", _PATH_ENVIRONMENT); #endif for (ep = env.envp; *ep; ep++) env_update_didvar(*ep, &didvar); } /* Pull in vars we want to keep from the old environment. */ if (env.old_envp != NULL) { for (ep = env.old_envp; *ep; ep++) { bool keepit; /* * Look up the variable in the env_check and env_keep lists. */ keepit = env_should_keep(ctx, *ep); /* * Do SUDO_PS1 -> PS1 conversion. * This must happen *after* env_should_keep() is called. */ if (strncmp(*ep, "SUDO_PS1=", 9) == 0) ps1 = *ep + 5; if (keepit) { /* Preserve variable. */ CHECK_PUTENV(*ep, true, false); env_update_didvar(*ep, &didvar); } } } didvar |= didvar << 16; /* convert DID_* to KEPT_* */ /* * Add in defaults. In -i mode these come from the runas user, * otherwise they may be from the user's environment (depends * on sudoers options). */ if (ISSET(ctx->mode, MODE_LOGIN_SHELL)) { CHECK_SETENV2("SHELL", ctx->runas.pw->pw_shell, ISSET(didvar, DID_SHELL), true); #ifdef _AIX CHECK_SETENV2("LOGIN", ctx->runas.pw->pw_name, ISSET(didvar, DID_LOGIN), true); #endif CHECK_SETENV2("LOGNAME", ctx->runas.pw->pw_name, ISSET(didvar, DID_LOGNAME), true); CHECK_SETENV2("USER", ctx->runas.pw->pw_name, ISSET(didvar, DID_USER), true); } else { /* We will set LOGNAME later in the def_set_logname case. */ if (!def_set_logname) { #ifdef _AIX if (!ISSET(didvar, DID_LOGIN)) CHECK_SETENV2("LOGIN", ctx->user.name, false, true); #endif if (!ISSET(didvar, DID_LOGNAME)) CHECK_SETENV2("LOGNAME", ctx->user.name, false, true); if (!ISSET(didvar, DID_USER)) CHECK_SETENV2("USER", ctx->user.name, false, true); } } /* If we didn't keep HOME, reset it based on target user. */ if (!ISSET(didvar, KEPT_HOME)) reset_home = true; /* * Set MAIL to target user in -i mode or if MAIL is not preserved * from user's environment. */ if (ISSET(ctx->mode, MODE_LOGIN_SHELL) || !ISSET(didvar, KEPT_MAIL)) { if (_PATH_MAILDIR[sizeof(_PATH_MAILDIR) - 2] == '/') { len = asprintf(&cp, "MAIL=%s%s", _PATH_MAILDIR, ctx->runas.pw->pw_name); } else { len = asprintf(&cp, "MAIL=%s/%s", _PATH_MAILDIR, ctx->runas.pw->pw_name); } if (len == -1) goto bad; if (sudo_putenv(cp, ISSET(didvar, DID_MAIL), true) == -1) { free(cp); goto bad; } sudoers_gc_add(GC_PTR, cp); } } else { /* * Copy environ entries as long as they don't match env_delete or * env_check. */ if (env.old_envp != NULL) { for (ep = env.old_envp; *ep; ep++) { /* Add variable unless it matches a blocklist. */ if (!env_should_delete(*ep)) { if (strncmp(*ep, "SUDO_PS1=", 9) == 0) ps1 = *ep + 5; else if (strncmp(*ep, "SHELL=", 6) == 0) SET(didvar, DID_SHELL); else if (strncmp(*ep, "PATH=", 5) == 0) SET(didvar, DID_PATH); else if (strncmp(*ep, "TERM=", 5) == 0) SET(didvar, DID_TERM); CHECK_PUTENV(*ep, true, false); } } } } /* Replace the PATH envariable with a secure one? */ if (def_secure_path && !user_is_exempt(ctx)) { CHECK_SETENV2("PATH", def_secure_path, true, true); SET(didvar, DID_PATH); } /* * Set LOGIN, LOGNAME, and USER to target if "set_logname" is not * disabled. We skip this if we are running a login shell (because * they have already been set). */ if (def_set_logname && !ISSET(ctx->mode, MODE_LOGIN_SHELL)) { if ((didvar & KEPT_USER_VARIABLES) == 0) { /* Nothing preserved, set them all. */ #ifdef _AIX CHECK_SETENV2("LOGIN", ctx->runas.pw->pw_name, true, true); #endif CHECK_SETENV2("LOGNAME", ctx->runas.pw->pw_name, true, true); CHECK_SETENV2("USER", ctx->runas.pw->pw_name, true, true); } else if ((didvar & KEPT_USER_VARIABLES) != KEPT_USER_VARIABLES) { /* * Preserved some of LOGIN, LOGNAME, USER but not all. * Make the unset ones match so we don't end up with some * set to the invoking user and others set to the runas user. */ if (ISSET(didvar, KEPT_LOGNAME)) cp = sudo_getenv("LOGNAME"); #ifdef _AIX else if (ISSET(didvar, KEPT_LOGIN)) cp = sudo_getenv("LOGIN"); #endif else if (ISSET(didvar, KEPT_USER)) cp = sudo_getenv("USER"); else cp = NULL; if (cp != NULL) { #ifdef _AIX if (!ISSET(didvar, KEPT_LOGIN)) CHECK_SETENV2("LOGIN", cp, true, true); #endif if (!ISSET(didvar, KEPT_LOGNAME)) CHECK_SETENV2("LOGNAME", cp, true, true); if (!ISSET(didvar, KEPT_USER)) CHECK_SETENV2("USER", cp, true, true); } } } /* Set $HOME to target user if not preserving user's value. */ if (reset_home) CHECK_SETENV2("HOME", ctx->runas.pw->pw_dir, true, true); /* Provide default values for $SHELL, $TERM and $PATH if not set. */ if (!ISSET(didvar, DID_SHELL)) CHECK_SETENV2("SHELL", ctx->runas.pw->pw_shell, false, false); if (!ISSET(didvar, DID_TERM)) CHECK_PUTENV("TERM=unknown", false, false); if (!ISSET(didvar, DID_PATH)) CHECK_SETENV2("PATH", _PATH_STDPATH, false, true); /* Set PS1 if SUDO_PS1 is set. */ if (ps1 != NULL) CHECK_PUTENV(ps1, true, true); /* Add the SUDO_COMMAND envariable (cmnd + args). */ if (ctx->user.cmnd_args) { /* * We limit ctx->user.cmnd_args to 4096 bytes to avoid an execve(2) * failure for very long argument vectors. The command's environment * also counts against the ARG_MAX limit. */ len = asprintf(&cp, "SUDO_COMMAND=%s %.*s", ctx->user.cmnd, 4096, ctx->user.cmnd_args); if (len == -1) goto bad; if (sudo_putenv(cp, true, true) == -1) { free(cp); goto bad; } sudoers_gc_add(GC_PTR, cp); } else { CHECK_SETENV2("SUDO_COMMAND", ctx->user.cmnd, true, true); } /* Add the SUDO_USER, SUDO_UID, SUDO_GID environment variables. */ CHECK_SETENV2("SUDO_USER", ctx->user.name, true, true); (void)snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int) ctx->user.uid); CHECK_SETENV2("SUDO_UID", idbuf, true, true); (void)snprintf(idbuf, sizeof(idbuf), "%u", (unsigned int) ctx->user.gid); CHECK_SETENV2("SUDO_GID", idbuf, true, true); debug_return_bool(true); bad: sudo_warn("%s", U_("unable to rebuild the environment")); debug_return_bool(false); } /* * Insert all environment variables in envp into the private copy * of the environment. * Returns true on success or false on failure. */ bool insert_env_vars(char * const envp[]) { char * const *ep; bool ret = true; debug_decl(insert_env_vars, SUDOERS_DEBUG_ENV); /* Add user-specified environment variables. */ if (envp != NULL) { for (ep = envp; *ep != NULL; ep++) { /* XXX - no undo on failure */ if (sudo_putenv(*ep, true, true) == -1) { ret = false; break; } } } debug_return_bool(ret); } /* * Validate the list of environment variables passed in on the command * line against env_delete, env_check, and env_keep. * Calls log_warning() if any specified variables are not allowed. * Returns true if allowed, else false. */ bool validate_env_vars(const struct sudoers_context *ctx, char * const env_vars[]) { char * const *ep; char errbuf[4096]; char *errpos = errbuf; bool okvar, ret = true; debug_decl(validate_env_vars, SUDOERS_DEBUG_ENV); if (env_vars == NULL) debug_return_bool(true); /* nothing to do */ /* Add user-specified environment variables. */ for (ep = env_vars; *ep != NULL; ep++) { char *eq = strchr(*ep, '='); if (eq == NULL || eq == *ep) { /* Must be in the form var=val. */ okvar = false; } else if (def_secure_path && !user_is_exempt(ctx) && strncmp(*ep, "PATH=", 5) == 0) { okvar = false; } else if (def_env_reset) { okvar = env_should_keep(ctx, *ep); } else { okvar = !env_should_delete(*ep); } if (okvar == false) { /* Not allowed, append to error buffer if space remains. */ if (errpos < &errbuf[sizeof(errbuf)]) { const size_t varlen = strcspn(*ep, "="); const size_t errsize = sizeof(errbuf) - (size_t)(errpos - errbuf); int len = snprintf(errpos, errsize, "%s%.*s", errpos != errbuf ? ", " : "", (int)varlen, *ep); if (len >= ssizeof(errbuf) - (errpos - errbuf)) { memcpy(&errbuf[sizeof(errbuf) - 4], "...", 4); errpos = &errbuf[sizeof(errbuf)]; } else { errpos += len; } } } } if (errpos != errbuf) { /* XXX - audit? */ log_warningx(ctx, 0, N_("sorry, you are not allowed to set the following environment variables: %s"), errbuf); ret = false; } debug_return_bool(ret); } static void * env_file_open_local(const char *path) { struct env_file_local *efl; debug_decl(env_file_open_local, SUDOERS_DEBUG_ENV); efl = calloc(1, sizeof(*efl)); if (efl != NULL) { if ((efl->fp = fopen(path, "r")) == NULL) { if (errno != ENOENT) { free(efl); efl = NULL; } } } debug_return_ptr(efl); } static void env_file_close_local(void *cookie) { struct env_file_local *efl = cookie; debug_decl(env_file_close_local, SUDOERS_DEBUG_ENV); if (efl != NULL) { if (efl->fp != NULL) fclose(efl->fp); free(efl->line); free(efl); } debug_return; } /* * Parse /etc/environment lines ala AIX and Linux. * Lines may be in either of three formats: * NAME=VALUE * NAME="VALUE" * NAME='VALUE' * with an optional "export" prefix so the shell can source the file. * Invalid lines, blank lines, or lines consisting solely of a comment * character are skipped. */ static char * env_file_next_local(void *cookie, int *errnum) { struct env_file_local *efl = cookie; char *var, *val, *ret = NULL; size_t var_len, val_len; debug_decl(env_file_next_local, SUDOERS_DEBUG_ENV); *errnum = 0; if (efl->fp == NULL) debug_return_ptr(NULL); for (;;) { if (sudo_parseln(&efl->line, &efl->linesize, NULL, efl->fp, PARSELN_CONT_IGN) == -1) { if (!feof(efl->fp)) *errnum = errno; break; } /* Skip blank or comment lines */ if (*(var = efl->line) == '\0') continue; /* Skip optional "export " */ if (strncmp(var, "export", 6) == 0 && isspace((unsigned char) var[6])) { var += 7; while (isspace((unsigned char) *var)) { var++; } } /* Must be of the form name=["']value['"] */ for (val = var; *val != '\0' && *val != '='; val++) continue; if (var == val || *val != '=') continue; var_len = (size_t)(val - var); val_len = strlen(++val); /* Strip leading and trailing single/double quotes */ if ((val[0] == '\'' || val[0] == '\"') && val_len > 1 && val[0] == val[val_len - 1]) { val[val_len - 1] = '\0'; val++; val_len -= 2; } if ((ret = malloc(var_len + 1 + val_len + 1)) == NULL) { *errnum = errno; sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); } else { memcpy(ret, var, var_len + 1); /* includes '=' */ memcpy(ret + var_len + 1, val, val_len + 1); /* includes NUL */ sudoers_gc_add(GC_PTR, ret); } break; } debug_return_str(ret); } static struct sudoers_env_file env_file_sudoers = { env_file_open_local, env_file_close_local, env_file_next_local }; static struct sudoers_env_file env_file_system = { env_file_open_local, env_file_close_local, env_file_next_local }; void register_env_file(void * (*ef_open)(const char *), void (*ef_close)(void *), char * (*ef_next)(void *, int *), bool sys) { struct sudoers_env_file *ef = sys ? &env_file_system : &env_file_sudoers; ef->open = ef_open; ef->close = ef_close; ef->next = ef_next; } bool read_env_file(const struct sudoers_context *ctx, const char *path, bool overwrite, bool restricted) { struct sudoers_env_file *ef; bool ret = true; char *envstr; void *cookie; int errnum; debug_decl(read_env_file, SUDOERS_DEBUG_ENV); /* * The environment file may be handled differently depending on * whether it is specified in sudoers or the system. */ if (path == def_env_file || path == def_restricted_env_file) ef = &env_file_sudoers; else ef = &env_file_system; cookie = ef->open(path); if (cookie == NULL) debug_return_bool(false); for (;;) { /* Keep reading until EOF or error. */ if ((envstr = ef->next(cookie, &errnum)) == NULL) { if (errnum != 0) ret = false; break; } /* * If the env file is restricted, apply env_check and env_keep * when env_reset is set or env_delete when it is not. */ if (restricted) { if (def_env_reset ? !env_should_keep(ctx, envstr) : env_should_delete(envstr)) { free(envstr); continue; } } if (sudo_putenv(envstr, true, overwrite) == -1) { /* XXX - no undo on failure */ ret = false; break; } } ef->close(cookie); debug_return_bool(ret); } bool init_envtables(void) { struct list_member *cur; const char **p; debug_decl(init_envtables, SUDOERS_DEBUG_ENV); /* Fill in the "env_delete" list. */ for (p = initial_badenv_table; *p; p++) { cur = calloc(1, sizeof(struct list_member)); if (cur == NULL || (cur->value = strdup(*p)) == NULL) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); free(cur); debug_return_bool(false); } SLIST_INSERT_HEAD(&def_env_delete, cur, entries); } /* Fill in the "env_check" list. */ for (p = initial_checkenv_table; *p; p++) { cur = calloc(1, sizeof(struct list_member)); if (cur == NULL || (cur->value = strdup(*p)) == NULL) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); free(cur); debug_return_bool(false); } SLIST_INSERT_HEAD(&def_env_check, cur, entries); } /* Fill in the "env_keep" list. */ for (p = initial_keepenv_table; *p; p++) { cur = calloc(1, sizeof(struct list_member)); if (cur == NULL || (cur->value = strdup(*p)) == NULL) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "unable to allocate memory"); free(cur); debug_return_bool(false); } SLIST_INSERT_HEAD(&def_env_keep, cur, entries); } debug_return_bool(true); }