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-rw-r--r--usr.bin/sudo/env.c487
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diff --git a/usr.bin/sudo/env.c b/usr.bin/sudo/env.c
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+/*
+ * Copyright (c) 2000, 2001 Todd C. Miller <Todd.Miller@courtesan.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * 4. Products derived from this software may not be called "Sudo" nor
+ * may "Sudo" appear in their names without specific prior written
+ * permission from the author.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#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 */
+#include <pwd.h>
+#include <errno.h>
+
+#include "sudo.h"
+
+#ifndef lint
+static const char rcsid[] = "$Sudo: env.c,v 1.13 2001/12/31 05:53:23 millert Exp $";
+#endif /* lint */
+
+/*
+ * Flags used in env_reset()
+ */
+#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 0x12
+
+/*
+ * Prototypes
+ */
+char **rebuild_env __P((int, char **));
+char **zero_env __P((char **));
+static void insert_env __P((char **, char *));
+static char *format_env __P((char *, char *));
+
+/*
+ * Default table of "bad" variables to remove from the environment.
+ * XXX - how to omit TERMCAP if it starts with '/'?
+ */
+char *initial_badenv_table[] = {
+ "IFS",
+ "LOCALDOMAIN",
+ "RES_OPTIONS",
+ "HOSTALIASES",
+ "NLSPATH",
+ "PATH_LOCALE",
+ "LD_*",
+ "_RLD*",
+#ifdef __hpux
+ "SHLIB_PATH",
+#endif /* __hpux */
+#ifdef _AIX
+ "LIBPATH",
+#endif /* _AIX */
+#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.
+ */
+char *initial_checkenv_table[] = {
+ "LC_*",
+ "LANG",
+ "LANGUAGE",
+ NULL
+};
+
+/*
+ * Zero out environment and replace with a minimal set of
+ * 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;
+{
+ char **ep, **nep;
+ static char *newenv[7];
+
+ for (ep = envp; *ep; ep++) {
+ switch (**ep) {
+ case 'H':
+ if (strncmp("HOME=", *ep, 5) == 0)
+ break;
+ case 'L':
+ if (strncmp("LOGNAME=", *ep, 8) == 0)
+ break;
+ case 'P':
+ if (strncmp("PATH=", *ep, 5) == 0) {
+ user_path = *ep + 5;
+ /* XXX - set to sane default instead of user's? */
+ break;
+ }
+ case 'S':
+ if (strncmp("SHELL=", *ep, 6) == 0) {
+ user_shell = *ep + 6;
+ continue;
+ } else if (!user_prompt && !strncmp("SUDO_PROMPT=", *ep, 12)) {
+ user_prompt = *ep + 12;
+ continue;
+ }
+ case 'T':
+ if (strncmp("TZ=", *ep, 3) == 0)
+ break;
+ case 'U':
+ if (strncmp("USER=", *ep, 5) == 0)
+ break;
+ default:
+ continue;
+ }
+
+ /* Deal with multiply defined variables (take first instance) */
+ for (nep = newenv; *nep; nep++) {
+ if (**nep == **ep)
+ break;
+ }
+ if (*nep == NULL)
+ *nep++ = *ep;
+ }
+ return(&newenv[0]);
+}
+
+/*
+ * Given a variable and value, allocate and format an environment string.
+ */
+static char *
+format_env(var, val)
+ char *var;
+ char *val;
+{
+ char *estring, *p;
+ size_t varlen, vallen;
+
+ varlen = strlen(var);
+ vallen = strlen(val);
+ p = estring = (char *) emalloc(varlen + vallen + 2);
+ strcpy(p, var);
+ p += varlen;
+ *p++ = '=';
+ strcpy(p, val);
+
+ return(estring);
+}
+
+/*
+ * Insert str into envp.
+ * Assumes str has an '=' in it and does not check for available space!
+ */
+static void
+insert_env(envp, str)
+ char **envp;
+ char *str;
+{
+ char **ep;
+ size_t varlen;
+
+ varlen = (strchr(str, '=') - str) + 1;
+
+ for (ep = envp; *ep; ep++) {
+ if (strncmp(str, *ep, varlen) == 0) {
+ *ep = str;
+ break;
+ }
+ }
+ if (*ep == NULL) {
+ *ep++ = str;
+ *ep = 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(sudo_mode, envp)
+ int sudo_mode;
+ char **envp;
+{
+ char **newenvp, **ep, **nep, *cp, *ps1;
+ int okvar, iswild, didvar;
+ size_t env_size, len;
+ struct list_member *cur;
+
+ /* Count number of items in "env_keep" list (if any) */
+ for (len = 0, cur = def_list(I_ENV_KEEP); cur; cur = cur->next)
+ len++;
+
+ /*
+ * Either clean out the environment or reset to a safe default.
+ */
+ ps1 = NULL;
+ didvar = 0;
+ if (def_flag(I_ENV_RESET)) {
+ int keepit;
+
+ /* Alloc space for new environment. */
+ env_size = 32 + len;
+ nep = newenvp = (char **) emalloc(env_size * sizeof(char *));
+
+ /* Pull in vars we want to keep from the old environment. */
+ for (ep = envp; *ep; ep++) {
+ keepit = 0;
+ for (cur = def_list(I_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)
+ didvar |= DID_HOME;
+ break;
+ case 'S':
+ if (strncmp(*ep, "SHELL=", 6) == 0)
+ didvar |= DID_SHELL;
+ break;
+ case 'L':
+ if (strncmp(*ep, "LOGNAME=", 8) == 0)
+ didvar |= DID_LOGNAME;
+ break;
+ case 'U':
+ if (strncmp(*ep, "USER=", 5) == 0)
+ didvar |= DID_USER;
+ break;
+ }
+ *nep++ = *ep;
+ } else {
+ /* Preserve TERM and PATH, ignore anything else. */
+ if (!(didvar & DID_TERM) && !strncmp(*ep, "TERM=", 5)) {
+ *nep++ = *ep;
+ didvar |= DID_TERM;
+ } else if (!(didvar & DID_PATH) && !strncmp(*ep, "PATH=", 5)) {
+ *nep++ = *ep;
+ didvar |= DID_PATH;
+ }
+ }
+ }
+
+ /*
+ * Add in defaults unless they were preserved from the
+ * user's environment.
+ */
+ if (!(didvar & DID_HOME))
+ *nep++ = format_env("HOME", user_dir);
+ if (!(didvar & DID_SHELL))
+ *nep++ = format_env("SHELL", user_shell);
+ if (!(didvar & DID_LOGNAME))
+ *nep++ = format_env("LOGNAME", user_name);
+ if (!(didvar & DID_USER))
+ *nep++ = format_env("USER", user_name);
+ } else {
+ /* Alloc space for new environment. */
+ for (env_size = 16 + len, ep = envp; *ep; ep++, env_size++)
+ ;
+ nep = newenvp = (char **) emalloc(env_size * sizeof(char *));
+
+ /*
+ * Copy envp entries as long as they don't match env_delete or
+ * env_check.
+ */
+ for (ep = envp; *ep; ep++) {
+ okvar = 1;
+
+ /* Skip anything listed in env_delete. */
+ for (cur = def_list(I_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_list(I_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)
+ didvar |= DID_PATH;
+ else if (strncmp(*ep, "TERM=", 5) == 0)
+ didvar |= DID_TERM;
+ *nep++ = *ep;
+ }
+ }
+ }
+ /* Provide default values for $TERM and $PATH if they are not set. */
+ if (!(didvar & DID_TERM))
+ *nep++ = "TERM=unknown";
+ if (!(didvar & DID_PATH))
+ *nep++ = format_env("PATH", _PATH_DEFPATH);
+ *nep = NULL;
+
+ /*
+ * At this point we must use insert_env() to modify newenvp.
+ * Access via 'nep' is not allowed (since we must check for dupes).
+ */
+
+#ifdef SECURE_PATH
+ /* Replace the PATH envariable with a secure one. */
+ insert_env(newenvp, format_env("PATH", SECURE_PATH));
+#endif
+
+ /* Set $USER and $LOGNAME to target if "set_logname" is true. */
+ if (def_flag(I_SET_LOGNAME) && runas_pw->pw_name) {
+ insert_env(newenvp, format_env("LOGNAME", runas_pw->pw_name));
+ insert_env(newenvp, format_env("USER", runas_pw->pw_name));
+ }
+
+ /* Set $HOME for `sudo -H'. Only valid at PERM_RUNAS. */
+ if ((sudo_mode & MODE_RESET_HOME) && runas_pw->pw_dir)
+ insert_env(newenvp, format_env("HOME", runas_pw->pw_dir));
+
+ /* Set PS1 if SUDO_PS1 is set. */
+ if (ps1)
+ insert_env(newenvp, ps1);
+
+ /* Add the SUDO_COMMAND envariable (cmnd + args). */
+ if (user_args) {
+ cp = emalloc(strlen(user_cmnd) + strlen(user_args) + 15);
+ sprintf(cp, "SUDO_COMMAND=%s %s", user_cmnd, user_args);
+ insert_env(newenvp, cp);
+ } else
+ insert_env(newenvp, format_env("SUDO_COMMAND", user_cmnd));
+
+ /* Add the SUDO_USER, SUDO_UID, SUDO_GID environment variables. */
+ insert_env(newenvp, format_env("SUDO_USER", user_name));
+ cp = emalloc(MAX_UID_T_LEN + 10);
+ sprintf(cp, "SUDO_UID=%ld", (long) user_uid);
+ insert_env(newenvp, cp);
+ cp = emalloc(MAX_UID_T_LEN + 10);
+ sprintf(cp, "SUDO_GID=%ld", (long) user_gid);
+ insert_env(newenvp, cp);
+
+ return(newenvp);
+}
+
+void
+dump_badenv()
+{
+ struct list_member *cur;
+
+ puts("Default table of environment variables to clear");
+ for (cur = def_list(I_ENV_DELETE); cur; cur = cur->next)
+ printf("\t%s\n", cur->value);
+
+ puts("Default table of environment variables to sanity check");
+ for (cur = def_list(I_ENV_CHECK); cur; cur = cur->next)
+ printf("\t%s\n", cur->value);
+}
+
+void
+init_envtables()
+{
+ struct list_member *cur;
+ 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_list(I_ENV_DELETE);
+ def_list(I_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_list(I_ENV_CHECK);
+ def_list(I_ENV_CHECK) = cur;
+ }
+}
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