/* * Copyright (c) 2000-2007 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. */ #include #include #include #include #include #ifdef STDC_HEADERS # include # include #else # ifdef HAVE_STDLIB_H # include # endif #endif /* STDC_HEADERS */ #ifdef HAVE_STRING_H # include #else # ifdef HAVE_STRINGS_H # include # endif #endif /* HAVE_STRING_H */ #ifdef HAVE_UNISTD_H # include #endif /* HAVE_UNISTD_H */ #ifdef HAVE_ERR_H # include #else # include "emul/err.h" #endif /* HAVE_ERR_H */ #include #include "sudo.h" #ifndef lint __unused static const char rcsid[] = "$Sudo: env.c,v 1.39.2.19 2008/06/21 19:04:07 millert Exp $"; #endif /* lint */ /* * Flags used in rebuild_env() */ #undef DID_TERM #define DID_TERM 0x0001 #undef DID_PATH #define DID_PATH 0x0002 #undef DID_HOME #define DID_HOME 0x0004 #undef DID_SHELL #define DID_SHELL 0x0008 #undef DID_LOGNAME #define DID_LOGNAME 0x0010 #undef DID_USER #define DID_USER 0x0020 #undef DID_USERNAME #define DID_USERNAME 0x0040 #undef DID_MAX #define DID_MAX 0x00ff #undef KEPT_TERM #define KEPT_TERM 0x0100 #undef KEPT_PATH #define KEPT_PATH 0x0200 #undef KEPT_HOME #define KEPT_HOME 0x0400 #undef KEPT_SHELL #define KEPT_SHELL 0x0800 #undef KEPT_LOGNAME #define KEPT_LOGNAME 0x1000 #undef KEPT_USER #define KEPT_USER 0x2000 #undef KEPT_USERNAME #define KEPT_USERNAME 0x4000 #undef KEPT_MAX #define KEPT_MAX 0xff00 #undef VNULL #define VNULL (VOID *)NULL struct environment { char **envp; /* pointer to the new environment */ size_t env_size; /* size of new_environ in char **'s */ size_t env_len; /* number of slots used, not counting NULL */ }; /* * Prototypes */ char **rebuild_env __P((char **, int, int)); static void insert_env __P((char *, struct environment *, int)); static char *format_env __P((char *, ...)); /* * 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", #endif #ifdef __APPLE__ "DYLD_*", #endif #ifdef HAVE_KERB4 "KRB_CONF*", "KRBCONFDIR", "KRBTKFILE", #endif /* HAVE_KERB4 */ #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 */ "SHELLOPTS", /* bash, extra command line 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 */ "RUBYLIB", /* ruby, library load path */ "RUBYOPT", /* ruby, extra command line options */ NULL }; /* * Default table of variables to check for '%' and '/' characters. */ static const char *initial_checkenv_table[] = { "COLORTERM", "LANG", "LANGUAGE", "LC_*", "LINGUAS", "TERM", NULL }; /* * Default table of variables to preserve in the environment. */ static const char *initial_keepenv_table[] = { "COLORS", "DISPLAY", "HOME", "HOSTNAME", "KRB5CCNAME", "LS_COLORS", "MAIL", "PATH", "PS1", "PS2", "TZ", "XAUTHORITY", "XAUTHORIZATION", NULL }; /* * Given a variable and value, allocate and format an environment string. */ static char * #ifdef __STDC__ format_env(char *var, ...) #else format_env(var, va_alist) char *var; va_dcl #endif { char *estring; char *val; size_t esize; va_list ap; #ifdef __STDC__ va_start(ap, var); #else va_start(ap); #endif esize = strlen(var) + 2; while ((val = va_arg(ap, char *)) != NULL) esize += strlen(val); va_end(ap); estring = (char *) emalloc(esize); /* Store variable name and the '=' separator. */ if (strlcpy(estring, var, esize) >= esize || strlcat(estring, "=", esize) >= esize) { errx(1, "internal error, format_env() overflow"); } /* Now store the variable's value (if any) */ #ifdef __STDC__ va_start(ap, var); #else va_start(ap); #endif while ((val = va_arg(ap, char *)) != NULL) { if (strlcat(estring, val, esize) >= esize) errx(1, "internal error, format_env() overflow"); } va_end(ap); return(estring); } /* * Insert str into e->envp, assumes str has an '=' in it. */ static void insert_env(str, e, dupcheck) char *str; struct environment *e; int dupcheck; { char **nep; size_t varlen; /* Make sure there is room for the new entry plus a NULL. */ if (e->env_len + 2 > e->env_size) { e->env_size += 128; e->envp = erealloc3(e->envp, e->env_size, sizeof(char *)); } if (dupcheck) { varlen = (strchr(str, '=') - str) + 1; for (nep = e->envp; *nep; nep++) { if (strncmp(str, *nep, varlen) == 0) { *nep = str; return; } } } else nep = e->envp + e->env_len; e->env_len++; *nep++ = str; *nep = NULL; } /* * Check the env_delete blacklist. * Returns TRUE if the variable was found, else false. */ static int matches_env_delete(var) const char *var; { struct list_member *cur; size_t len; int iswild, match = FALSE; /* Skip anything listed in env_delete. */ for (cur = def_env_delete; cur; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = TRUE; } else iswild = FALSE; if (strncmp(cur->value, var, len) == 0 && (iswild || var[len] == '=')) { match = TRUE; break; } } return(match); } /* * 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(var) const char *var; { struct list_member *cur; size_t len; int iswild, keepit = -1; for (cur = def_env_check; cur; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = TRUE; } else iswild = FALSE; if (strncmp(cur->value, var, len) == 0 && (iswild || var[len] == '=')) { keepit = !strpbrk(var, "/%"); break; } } return(keepit); } /* * Check the env_keep list. * Returns TRUE if the variable is allowed else FALSE. */ static int matches_env_keep(var) const char *var; { struct list_member *cur; size_t len; int iswild, keepit = FALSE; for (cur = def_env_keep; cur; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = TRUE; } else iswild = FALSE; if (strncmp(cur->value, var, len) == 0 && (iswild || var[len] == '=')) { keepit = TRUE; break; } } return(keepit); } /* * Build a new environment and ether clear potentially dangerous * variables from the old one or start with a clean slate. * Also adds sudo-specific variables (SUDO_*). */ char ** rebuild_env(envp, sudo_mode, noexec) char **envp; int sudo_mode; int noexec; { char **ep, *cp, *ps1; unsigned int didvar; /* * Either clean out the environment or reset to a safe default. */ ps1 = NULL; didvar = 0; memset(&env, 0, sizeof(env)); if (def_env_reset || ISSET(sudo_mode, MODE_LOGIN_SHELL)) { /* Pull in vars we want to keep from the old environment. */ for (ep = envp; *ep; ep++) { int keepit; /* Skip variables with values beginning with () (bash functions) */ if ((cp = strchr(*ep, '=')) != NULL) { if (strncmp(cp, "=() ", 3) == 0) continue; } /* * First check certain variables for '%' and '/' characters. * If no match there, check the keep list. * If nothing matched, we remove it from the environment. */ keepit = matches_env_check(*ep); if (keepit == -1) keepit = matches_env_keep(*ep); /* For SUDO_PS1 -> PS1 conversion. */ if (strncmp(*ep, "SUDO_PS1=", 8) == 0) ps1 = *ep + 5; if (keepit) { /* Preserve variable. */ switch (**ep) { case 'H': if (strncmp(*ep, "HOME=", 5) == 0) SET(didvar, DID_HOME); break; case 'L': if (strncmp(*ep, "LOGNAME=", 8) == 0) SET(didvar, DID_LOGNAME); 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); if (strncmp(*ep, "USERNAME=", 5) == 0) SET(didvar, DID_USERNAME); break; } insert_env(*ep, &env, 0); } } didvar |= didvar << 8; /* 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(sudo_mode, MODE_LOGIN_SHELL)) { insert_env(format_env("HOME", runas_pw->pw_dir, VNULL), &env, ISSET(didvar, DID_HOME)); insert_env(format_env("SHELL", runas_pw->pw_shell, VNULL), &env, ISSET(didvar, DID_SHELL)); insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), &env, ISSET(didvar, DID_LOGNAME)); insert_env(format_env("USER", runas_pw->pw_name, VNULL), &env, ISSET(didvar, DID_USER)); insert_env(format_env("USERNAME", runas_pw->pw_name, VNULL), &env, ISSET(didvar, DID_USERNAME)); } else { if (!ISSET(didvar, DID_HOME)) insert_env(format_env("HOME", user_dir, VNULL), &env, 0); if (!ISSET(didvar, DID_SHELL)) insert_env(format_env("SHELL", sudo_user.pw->pw_shell, VNULL), &env, 0); if (!ISSET(didvar, DID_LOGNAME)) insert_env(format_env("LOGNAME", user_name, VNULL), &env, 0); if (!ISSET(didvar, DID_USER)) insert_env(format_env("USER", user_name, VNULL), &env, 0); if (!ISSET(didvar, DID_USERNAME)) insert_env(format_env("USERNAME", user_name, VNULL), &env, 0); } } else { /* * Copy envp entries as long as they don't match env_delete or * env_check. */ for (ep = envp; *ep; ep++) { int okvar; /* Skip variables with values beginning with () (bash functions) */ if ((cp = strchr(*ep, '=')) != NULL) { if (strncmp(cp, "=() ", 3) == 0) continue; } /* * First check variables against the blacklist in env_delete. * If no match there check for '%' and '/' characters. */ okvar = matches_env_delete(*ep) != TRUE; if (okvar) okvar = matches_env_check(*ep) != FALSE; if (okvar) { if (strncmp(*ep, "SUDO_PS1=", 9) == 0) ps1 = *ep + 5; else if (strncmp(*ep, "PATH=", 5) == 0) SET(didvar, DID_PATH); else if (strncmp(*ep, "TERM=", 5) == 0) SET(didvar, DID_TERM); insert_env(*ep, &env, 0); } } } #ifdef SECURE_PATH /* Replace the PATH envariable with a secure one. */ if (!user_is_exempt()) { insert_env(format_env("PATH", SECURE_PATH, VNULL), &env, 1); SET(didvar, DID_PATH); } #endif /* Set $USER, $LOGNAME and $USERNAME to target if "set_logname" is true. */ /* XXX - not needed for MODE_LOGIN_SHELL */ if (def_set_logname && runas_pw->pw_name) { if (!ISSET(didvar, KEPT_LOGNAME)) insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), &env, 1); if (!ISSET(didvar, KEPT_USER)) insert_env(format_env("USER", runas_pw->pw_name, VNULL), &env, 1); if (!ISSET(didvar, KEPT_USERNAME)) insert_env(format_env("USERNAME", runas_pw->pw_name, VNULL), &env, 1); } /* Set $HOME for `sudo -H'. Only valid at PERM_FULL_RUNAS. */ /* XXX - not needed for MODE_LOGIN_SHELL */ if (runas_pw->pw_dir) { if (ISSET(sudo_mode, MODE_RESET_HOME) || (ISSET(sudo_mode, MODE_RUN) && (def_always_set_home || (ISSET(sudo_mode, MODE_SHELL) && def_set_home)))) insert_env(format_env("HOME", runas_pw->pw_dir, VNULL), &env, 1); } /* Provide default values for $TERM and $PATH if they are not set. */ if (!ISSET(didvar, DID_TERM)) insert_env("TERM=unknown", &env, 0); if (!ISSET(didvar, DID_PATH)) insert_env(format_env("PATH", _PATH_DEFPATH, VNULL), &env, 0); /* * Preload a noexec file? For a list of LD_PRELOAD-alikes, see * http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html * XXX - should prepend to original value, if any */ if (noexec && def_noexec_file != NULL) { #if defined(__darwin__) || defined(__APPLE__) insert_env(format_env("DYLD_INSERT_LIBRARIES", def_noexec_file, VNULL), &env, 1); insert_env(format_env("DYLD_FORCE_FLAT_NAMESPACE", VNULL), &env, 1); #else # if defined(__osf__) || defined(__sgi) insert_env(format_env("_RLD_LIST", def_noexec_file, ":DEFAULT", VNULL), &env, 1); # else # ifdef _AIX insert_env(format_env("LDR_PRELOAD", def_noexec_file, VNULL), &env, 1); # else insert_env(format_env("LD_PRELOAD", def_noexec_file, VNULL), &env, 1); # endif /* _AIX */ # endif /* __osf__ || __sgi */ #endif /* __darwin__ || __APPLE__ */ } /* Set PS1 if SUDO_PS1 is set. */ if (ps1) insert_env(ps1, &env, 1); /* Add the SUDO_COMMAND envariable (cmnd + args). */ if (user_args) insert_env(format_env("SUDO_COMMAND", user_cmnd, " ", user_args, VNULL), &env, 1); else insert_env(format_env("SUDO_COMMAND", user_cmnd, VNULL), &env, 1); /* Add the SUDO_USER, SUDO_UID, SUDO_GID environment variables. */ insert_env(format_env("SUDO_USER", user_name, VNULL), &env, 1); easprintf(&cp, "SUDO_UID=%lu", (unsigned long) user_uid); insert_env(cp, &env, 1); easprintf(&cp, "SUDO_GID=%lu", (unsigned long) user_gid); insert_env(cp, &env, 1); return(env.envp); } char ** insert_env_vars(envp, env_vars) char **envp; struct list_member *env_vars; { struct list_member *cur; if (env_vars == NULL) return (envp); /* * Make sure we still own the environment and steal it back if not. */ if (env.envp != envp) { size_t evlen; char **ep; for (ep = envp; *ep != NULL; ep++) continue; evlen = ep - envp; if (evlen + 1 > env.env_size) { efree(env.envp); env.env_size = evlen + 1 + 128; env.envp = emalloc2(env.env_size, sizeof(char *)); } memcpy(env.envp, envp, (evlen + 1) * sizeof(char *)); env.env_len = evlen; } /* Add user-specified environment variables. */ for (cur = env_vars; cur != NULL; cur = cur->next) insert_env(cur->value, &env, 1); return(env.envp); } /* * Validate the list of environment variables passed in on the command * line against env_delete, env_check, and env_keep. * Calls log_error() if any specified variables are not allowed. */ void validate_env_vars(env_vars) struct list_member *env_vars; { struct list_member *var; char *eq, *bad = NULL; size_t len, blen = 0, bsize = 0; int okvar; for (var = env_vars; var != NULL; var = var->next) { #ifdef SECURE_PATH if (!user_is_exempt() && strncmp(var->value, "PATH=", 5) == 0) { okvar = FALSE; } else #endif if (def_env_reset) { okvar = matches_env_check(var->value); if (okvar == -1) okvar = matches_env_keep(var->value); } else { okvar = matches_env_delete(var->value) == FALSE; if (okvar == FALSE) okvar = matches_env_check(var->value) != FALSE; } if (okvar == FALSE) { /* Not allowed, add to error string, allocating as needed. */ if ((eq = strchr(var->value, '=')) != NULL) *eq = '\0'; len = strlen(var->value) + 2; if (blen + len >= bsize) { do { bsize += 1024; } while (blen + len >= bsize); bad = erealloc(bad, bsize); bad[blen] = '\0'; } strlcat(bad, var->value, bsize); strlcat(bad, ", ", bsize); blen += len; if (eq != NULL) *eq = '='; } } if (bad != NULL) { bad[blen - 2] = '\0'; /* remove trailing ", " */ log_error(NO_MAIL, "sorry, you are not allowed to set the following environment variables: %s", bad); /* NOTREACHED */ efree(bad); } } void init_envtables() { struct list_member *cur; const char **p; /* Fill in the "env_delete" list. */ for (p = initial_badenv_table; *p; p++) { cur = emalloc(sizeof(struct list_member)); cur->value = estrdup(*p); cur->next = def_env_delete; def_env_delete = cur; } /* Fill in the "env_check" list. */ for (p = initial_checkenv_table; *p; p++) { cur = emalloc(sizeof(struct list_member)); cur->value = estrdup(*p); cur->next = def_env_check; def_env_check = cur; } /* Fill in the "env_keep" list. */ for (p = initial_keepenv_table; *p; p++) { cur = emalloc(sizeof(struct list_member)); cur->value = estrdup(*p); cur->next = def_env_keep; def_env_keep = cur; } }