/* * Copyright (c) 2000-2004 Todd C. Miller <Todd.Miller@courtesan.com> * * 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 "config.h" #include <sys/types.h> #include <sys/param.h> #include <sys/stat.h> #include <stdio.h> #ifdef STDC_HEADERS # include <stdlib.h> # include <stddef.h> #else # ifdef HAVE_STDLIB_H # include <stdlib.h> # endif #endif /* STDC_HEADERS */ #ifdef HAVE_STRING_H # include <string.h> #else # ifdef HAVE_STRINGS_H # include <strings.h> # endif #endif /* HAVE_STRING_H */ #ifdef HAVE_UNISTD_H # include <unistd.h> #endif /* HAVE_UNISTD_H */ #ifdef HAVE_ERR_H # include <err.h> #else # include "emul/err.h" #endif /* HAVE_ERR_H */ #include <pwd.h> #include "sudo.h" #ifndef lint static const char rcsid[] = "$Sudo: env.c,v 1.42 2004/09/08 15:57:49 millert Exp $"; #endif /* lint */ /* * Flags used in rebuild_env() */ #undef DID_TERM #define DID_TERM 0x01 #undef DID_PATH #define DID_PATH 0x02 #undef DID_HOME #define DID_HOME 0x04 #undef DID_SHELL #define DID_SHELL 0x08 #undef DID_LOGNAME #define DID_LOGNAME 0x10 #undef DID_USER #define DID_USER 0x20 #undef VNULL #define VNULL (VOID *)NULL /* * Prototypes */ char **rebuild_env __P((char **, int, int)); char **zero_env __P((char **)); static void insert_env __P((char *, int)); static char *format_env __P((char *, ...)); /* * 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 "LIBPATH", #endif /* _AIX */ #ifdef __APPLE__ "DYLD_*", #endif #ifdef HAVE_KERB4 "KRB_CONF*", "KRBCONFDIR", "KRBTKFILE", #endif /* HAVE_KERB4 */ #ifdef HAVE_KERB5 "KRB5_CONFIG*", #endif /* HAVE_KERB5 */ #ifdef HAVE_SECURID "VAR_ACE", "USR_ACE", "DLC_ACE", #endif /* HAVE_SECURID */ "TERMINFO", "TERMINFO_DIRS", "TERMPATH", "TERMCAP", /* XXX - only if it starts with '/' */ "ENV", "BASH_ENV", NULL }; /* * Default table of variables to check for '%' and '/' characters. */ static const char *initial_checkenv_table[] = { "LC_*", "LANG", "LANGUAGE", NULL }; static char **new_environ; /* Modified copy of the environment */ static size_t env_size; /* size of new_environ in char **'s */ static size_t env_len; /* number of slots used, not counting NULL */ /* * Zero out environment and replace with a minimal set of KRB5CCNAME * USER, LOGNAME, HOME, TZ, PATH (XXX - should just set path to default) * May set user_path, user_shell, and/or user_prompt as side effects. */ char ** zero_env(envp) char **envp; { static char *newenv[9]; char **ep, **nep = newenv; char **ne_last = &newenv[(sizeof(newenv) / sizeof(newenv[0])) - 1]; extern char *prev_user; for (ep = envp; *ep; ep++) { switch (**ep) { case 'H': if (strncmp("HOME=", *ep, 5) == 0) break; continue; case 'K': if (strncmp("KRB5CCNAME=", *ep, 11) == 0) break; continue; case 'L': if (strncmp("LOGNAME=", *ep, 8) == 0) break; continue; case 'P': if (strncmp("PATH=", *ep, 5) == 0) { user_path = *ep + 5; /* XXX - set to sane default instead of user's? */ break; } continue; case 'S': if (strncmp("SHELL=", *ep, 6) == 0) user_shell = *ep + 6; else if (!user_prompt && strncmp("SUDO_PROMPT=", *ep, 12) == 0) user_prompt = *ep + 12; else if (strncmp("SUDO_USER=", *ep, 10) == 0) prev_user = *ep + 10; continue; case 'T': if (strncmp("TZ=", *ep, 3) == 0) break; continue; case 'U': if (strncmp("USER=", *ep, 5) == 0) break; continue; default: continue; } /* Deal with multiply defined variables (take first instance) */ for (nep = newenv; *nep; nep++) { if (**nep == **ep) break; } if (*nep == NULL) { if (nep < ne_last) *nep++ = *ep; else errx(1, "internal error, attempt to write outside newenv"); } } #ifdef HAVE_LDAP /* * Prevent OpenLDAP from reading any user dotfiles * or files in the current directory. * */ if (nep < ne_last) *nep++ = "LDAPNOINIT=1"; else errx(1, "internal error, attempt to write outside newenv"); #endif return(&newenv[0]); } /* * 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 new_environ, assumes str has an '=' in it. * NOTE: no other routines may modify new_environ, env_size, or env_len. */ static void insert_env(str, dupcheck) char *str; int dupcheck; { char **nep; size_t varlen; /* Make sure there is room for the new entry plus a NULL. */ if (env_len + 2 > env_size) { env_size += 128; new_environ = erealloc3(new_environ, env_size, sizeof(char *)); } if (dupcheck) { varlen = (strchr(str, '=') - str) + 1; for (nep = new_environ; *nep; nep++) { if (strncmp(str, *nep, varlen) == 0) { *nep = str; return; } } } else nep = &new_environ[env_len]; env_len++; *nep++ = str; *nep = NULL; } /* * 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; int okvar, iswild, didvar; size_t len; struct list_member *cur; /* * Either clean out the environment or reset to a safe default. */ ps1 = NULL; didvar = 0; if (def_env_reset) { int keepit; /* Pull in vars we want to keep from the old environment. */ for (ep = envp; *ep; ep++) { keepit = 0; /* Skip variables with values beginning with () (bash functions) */ if ((cp = strchr(*ep, '=')) != NULL) { if (strncmp(cp, "=() ", 3) == 0) continue; } for (cur = def_env_keep; cur; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = 1; } else iswild = 0; if (strncmp(cur->value, *ep, len) == 0 && (iswild || (*ep)[len] == '=')) { /* We always preserve TERM, no special treatment needed. */ if (strncmp(*ep, "TERM=", 5) != 0) keepit = 1; break; } } /* 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 'S': if (strncmp(*ep, "SHELL=", 6) == 0) SET(didvar, DID_SHELL); break; case 'L': if (strncmp(*ep, "LOGNAME=", 8) == 0) SET(didvar, DID_LOGNAME); break; case 'U': if (strncmp(*ep, "USER=", 5) == 0) SET(didvar, DID_USER); break; } insert_env(*ep, 0); } else { /* Preserve TERM and PATH, ignore anything else. */ if (!ISSET(didvar, DID_TERM) && strncmp(*ep, "TERM=", 5) == 0) { insert_env(*ep, 0); SET(didvar, DID_TERM); } else if (!ISSET(didvar, DID_PATH) && strncmp(*ep, "PATH=", 5) == 0) { insert_env(*ep, 0); SET(didvar, DID_PATH); } } } /* * 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), 0); insert_env(format_env("SHELL", runas_pw->pw_shell, VNULL), 0); insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), 0); insert_env(format_env("USER", runas_pw->pw_name, VNULL), 0); } else { if (!ISSET(didvar, DID_HOME)) insert_env(format_env("HOME", user_dir, VNULL), 0); if (!ISSET(didvar, DID_SHELL)) insert_env(format_env("SHELL", sudo_user.pw->pw_shell, VNULL), 0); if (!ISSET(didvar, DID_LOGNAME)) insert_env(format_env("LOGNAME", user_name, VNULL), 0); if (!ISSET(didvar, DID_USER)) insert_env(format_env("USER", user_name, VNULL), 0); } } else { /* * Copy envp entries as long as they don't match env_delete or * env_check. */ for (ep = envp; *ep; ep++) { okvar = 1; /* Skip variables with values beginning with () (bash functions) */ if ((cp = strchr(*ep, '=')) != NULL) { if (strncmp(cp, "=() ", 3) == 0) continue; } /* Skip anything listed in env_delete. */ for (cur = def_env_delete; cur && okvar; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = 1; } else iswild = 0; if (strncmp(cur->value, *ep, len) == 0 && (iswild || (*ep)[len] == '=')) { okvar = 0; } } /* Check certain variables for '%' and '/' characters. */ for (cur = def_env_check; cur && okvar; cur = cur->next) { len = strlen(cur->value); /* Deal with '*' wildcard */ if (cur->value[len - 1] == '*') { len--; iswild = 1; } else iswild = 0; if (strncmp(cur->value, *ep, len) == 0 && (iswild || (*ep)[len] == '=') && strpbrk(*ep, "/%")) { okvar = 0; } } 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, 0); } } } /* Provide default values for $TERM and $PATH if they are not set. */ if (!ISSET(didvar, DID_TERM)) insert_env("TERM=unknown", 0); if (!ISSET(didvar, DID_PATH)) insert_env(format_env("PATH", _PATH_DEFPATH, VNULL), 0); #ifdef SECURE_PATH /* Replace the PATH envariable with a secure one. */ insert_env(format_env("PATH", SECURE_PATH, VNULL), 1); #endif /* Set $USER and $LOGNAME to target if "set_logname" is true. */ if (def_set_logname && runas_pw->pw_name) { insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), 1); insert_env(format_env("USER", runas_pw->pw_name, VNULL), 1); } /* Set $HOME for `sudo -H'. Only valid at PERM_FULL_RUNAS. */ if (ISSET(sudo_mode, MODE_RESET_HOME) && runas_pw->pw_dir) insert_env(format_env("HOME", runas_pw->pw_dir, VNULL), 1); /* * 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), 1); insert_env(format_env("DYLD_FORCE_FLAT_NAMESPACE", VNULL), 1); #else # if defined(__osf__) || defined(__sgi) insert_env(format_env("_RLD_LIST", def_noexec_file, ":DEFAULT", VNULL), 1); # else insert_env(format_env("LD_PRELOAD", def_noexec_file, VNULL), 1); # endif #endif } /* Set PS1 if SUDO_PS1 is set. */ if (ps1) insert_env(ps1, 1); /* Add the SUDO_COMMAND envariable (cmnd + args). */ if (user_args) insert_env(format_env("SUDO_COMMAND", user_cmnd, " ", user_args, VNULL), 1); else insert_env(format_env("SUDO_COMMAND", user_cmnd, VNULL), 1); /* Add the SUDO_USER, SUDO_UID, SUDO_GID environment variables. */ insert_env(format_env("SUDO_USER", user_name, VNULL), 1); easprintf(&cp, "SUDO_UID=%lu", (unsigned long) user_uid); insert_env(cp, 1); easprintf(&cp, "SUDO_GID=%lu", (unsigned long) user_gid); insert_env(cp, 1); return(new_environ); } void init_envtables() { struct list_member *cur; const char **p; /* Fill in "env_delete" variable. */ 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 "env_check" variable. */ 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; } }