551 lines
14 KiB
C
551 lines
14 KiB
C
/*
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* Copyright (c) 2000-2004 Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Sponsored in part by the Defense Advanced Research Projects
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* Agency (DARPA) and Air Force Research Laboratory, Air Force
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* Materiel Command, USAF, under agreement number F39502-99-1-0512.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#ifdef HAVE_STRING_H
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# include <string.h>
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#else
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# ifdef HAVE_STRINGS_H
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# include <strings.h>
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# endif
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#include <pwd.h>
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#include "sudo.h"
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#ifndef lint
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static const char rcsid[] = "$Sudo$";
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#endif /* lint */
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/*
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* Flags used in rebuild_env()
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*/
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#undef DID_TERM
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#define DID_TERM 0x01
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#undef DID_PATH
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#define DID_PATH 0x02
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#undef DID_HOME
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#define DID_HOME 0x04
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#undef DID_SHELL
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#define DID_SHELL 0x08
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#undef DID_LOGNAME
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#define DID_LOGNAME 0x10
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#undef DID_USER
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#define DID_USER 0x12
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#undef VNULL
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#define VNULL (VOID *)NULL
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/*
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* Prototypes
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*/
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char **rebuild_env __P((char **, int, int));
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char **zero_env __P((char **));
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static void insert_env __P((char *, int));
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static char *format_env __P((char *, ...));
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/*
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* Default table of "bad" variables to remove from the environment.
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* XXX - how to omit TERMCAP if it starts with '/'?
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*/
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static const char *initial_badenv_table[] = {
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"IFS",
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"CDPATH",
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"LOCALDOMAIN",
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"RES_OPTIONS",
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"HOSTALIASES",
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"NLSPATH",
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"PATH_LOCALE",
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"LD_*",
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"_RLD*",
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#ifdef __hpux
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"SHLIB_PATH",
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#endif /* __hpux */
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#ifdef _AIX
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"LIBPATH",
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#endif /* _AIX */
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#ifdef __APPLE__
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"DYLD_*",
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#endif
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#ifdef HAVE_KERB4
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"KRB_CONF*",
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"KRBCONFDIR",
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"KRBTKFILE",
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#endif /* HAVE_KERB4 */
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#ifdef HAVE_KERB5
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"KRB5_CONFIG*",
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#endif /* HAVE_KERB5 */
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#ifdef HAVE_SECURID
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"VAR_ACE",
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"USR_ACE",
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"DLC_ACE",
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#endif /* HAVE_SECURID */
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"TERMINFO",
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"TERMINFO_DIRS",
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"TERMPATH",
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"TERMCAP", /* XXX - only if it starts with '/' */
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"ENV",
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"BASH_ENV",
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NULL
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};
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/*
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* Default table of variables to check for '%' and '/' characters.
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*/
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static const char *initial_checkenv_table[] = {
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"LC_*",
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"LANG",
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"LANGUAGE",
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NULL
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};
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static char **new_environ; /* Modified copy of the environment */
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static size_t env_size; /* size of new_environ in char **'s */
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static size_t env_len; /* number of slots used, not counting NULL */
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/*
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* Zero out environment and replace with a minimal set of KRB5CCNAME
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* USER, LOGNAME, HOME, TZ, PATH (XXX - should just set path to default)
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* May set user_path, user_shell, and/or user_prompt as side effects.
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*/
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char **
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zero_env(envp)
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char **envp;
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{
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static char *newenv[9];
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char **ep, **nep = newenv;
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char **ne_last = &newenv[(sizeof(newenv) / sizeof(newenv[0])) - 1];
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extern char *prev_user;
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for (ep = envp; *ep; ep++) {
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switch (**ep) {
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case 'H':
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if (strncmp("HOME=", *ep, 5) == 0)
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break;
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continue;
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case 'K':
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if (strncmp("KRB5CCNAME=", *ep, 11) == 0)
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break;
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continue;
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case 'L':
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if (strncmp("LOGNAME=", *ep, 8) == 0)
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break;
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continue;
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case 'P':
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if (strncmp("PATH=", *ep, 5) == 0) {
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user_path = *ep + 5;
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/* XXX - set to sane default instead of user's? */
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break;
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}
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continue;
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case 'S':
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if (strncmp("SHELL=", *ep, 6) == 0)
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user_shell = *ep + 6;
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else if (!user_prompt && strncmp("SUDO_PROMPT=", *ep, 12) == 0)
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user_prompt = *ep + 12;
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else if (strncmp("SUDO_USER=", *ep, 10) == 0)
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prev_user = *ep + 10;
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continue;
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case 'T':
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if (strncmp("TZ=", *ep, 3) == 0)
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break;
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continue;
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case 'U':
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if (strncmp("USER=", *ep, 5) == 0)
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break;
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continue;
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default:
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continue;
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}
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/* Deal with multiply defined variables (take first instance) */
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for (nep = newenv; *nep; nep++) {
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if (**nep == **ep)
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break;
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}
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if (*nep == NULL) {
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if (nep < ne_last)
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*nep++ = *ep;
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else
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errorx(1, "internal error, attempt to write outside newenv");
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}
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}
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#ifdef HAVE_LDAP
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/*
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* Prevent OpenLDAP from reading any user dotfiles
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* or files in the current directory.
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*
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*/
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if (nep < ne_last)
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*nep++ = "LDAPNOINIT=1";
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else
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errorx(1, "internal error, attempt to write outside newenv");
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#endif
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return(&newenv[0]);
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}
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/*
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* Given a variable and value, allocate and format an environment string.
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*/
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static char *
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#ifdef __STDC__
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format_env(char *var, ...)
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#else
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format_env(var, va_alist)
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char *var;
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va_dcl
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#endif
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{
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char *estring;
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char *val;
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size_t esize;
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va_list ap;
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#ifdef __STDC__
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va_start(ap, var);
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#else
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va_start(ap);
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#endif
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esize = strlen(var) + 2;
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while ((val = va_arg(ap, char *)) != NULL)
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esize += strlen(val);
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va_end(ap);
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estring = (char *) emalloc(esize);
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/* Store variable name and the '=' separator. */
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if (strlcpy(estring, var, esize) >= esize ||
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strlcat(estring, "=", esize) >= esize) {
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errorx(1, "internal error, format_env() overflow");
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}
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/* Now store the variable's value (if any) */
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#ifdef __STDC__
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va_start(ap, var);
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#else
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va_start(ap);
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#endif
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while ((val = va_arg(ap, char *)) != NULL) {
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if (strlcat(estring, val, esize) >= esize)
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errorx(1, "internal error, format_env() overflow");
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}
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va_end(ap);
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return(estring);
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}
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/*
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* Insert str into new_environ, assumes str has an '=' in it.
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* NOTE: no other routines may modify new_environ, env_size, or env_len.
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*/
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static void
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insert_env(str, dupcheck)
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char *str;
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int dupcheck;
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{
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char **nep;
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size_t varlen;
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/* Make sure there is room for the new entry plus a NULL. */
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if (env_len + 2 > env_size) {
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env_size += 128;
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new_environ = erealloc3(new_environ, env_size, sizeof(char *));
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}
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if (dupcheck) {
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varlen = (strchr(str, '=') - str) + 1;
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for (nep = new_environ; *nep; nep++) {
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if (strncmp(str, *nep, varlen) == 0) {
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*nep = str;
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return;
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}
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}
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} else
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nep = &new_environ[env_len];
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env_len++;
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*nep++ = str;
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*nep = NULL;
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}
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/*
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* Build a new environment and ether clear potentially dangerous
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* variables from the old one or start with a clean slate.
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* Also adds sudo-specific variables (SUDO_*).
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*/
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char **
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rebuild_env(envp, sudo_mode, noexec)
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char **envp;
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int sudo_mode;
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int noexec;
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{
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char **ep, *cp, *ps1;
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int okvar, iswild, didvar;
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size_t len;
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struct list_member *cur;
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/*
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* Either clean out the environment or reset to a safe default.
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*/
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ps1 = NULL;
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didvar = 0;
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if (def_env_reset) {
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int keepit;
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/* Pull in vars we want to keep from the old environment. */
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for (ep = envp; *ep; ep++) {
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keepit = 0;
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/* Skip variables with values beginning with () (bash functions) */
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if ((cp = strchr(*ep, '=')) != NULL) {
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if (strncmp(cp, "=() ", 3) == 0)
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continue;
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}
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for (cur = def_env_keep; cur; cur = cur->next) {
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len = strlen(cur->value);
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/* Deal with '*' wildcard */
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if (cur->value[len - 1] == '*') {
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len--;
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iswild = 1;
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} else
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iswild = 0;
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if (strncmp(cur->value, *ep, len) == 0 &&
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(iswild || (*ep)[len] == '=')) {
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/* We always preserve TERM, no special treatment needed. */
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if (strncmp(*ep, "TERM=", 5) != 0)
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keepit = 1;
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break;
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}
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}
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/* For SUDO_PS1 -> PS1 conversion. */
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if (strncmp(*ep, "SUDO_PS1=", 8) == 0)
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ps1 = *ep + 5;
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if (keepit) {
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/* Preserve variable. */
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switch (**ep) {
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case 'H':
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if (strncmp(*ep, "HOME=", 5) == 0)
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SET(didvar, DID_HOME);
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break;
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case 'S':
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if (strncmp(*ep, "SHELL=", 6) == 0)
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SET(didvar, DID_SHELL);
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break;
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case 'L':
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if (strncmp(*ep, "LOGNAME=", 8) == 0)
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SET(didvar, DID_LOGNAME);
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break;
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case 'U':
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if (strncmp(*ep, "USER=", 5) == 0)
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SET(didvar, DID_USER);
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break;
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}
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insert_env(*ep, 0);
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} else {
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/* Preserve TERM and PATH, ignore anything else. */
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if (!ISSET(didvar, DID_TERM) && strncmp(*ep, "TERM=", 5) == 0) {
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insert_env(*ep, 0);
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SET(didvar, DID_TERM);
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} else if (!ISSET(didvar, DID_PATH) && strncmp(*ep, "PATH=", 5) == 0) {
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insert_env(*ep, 0);
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SET(didvar, DID_PATH);
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}
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}
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}
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/*
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* Add in defaults. In -i mode these come from the runas user,
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* otherwise they may be from the user's environment (depends
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* on sudoers options).
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*/
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if (ISSET(sudo_mode, MODE_LOGIN_SHELL)) {
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insert_env(format_env("HOME", runas_pw->pw_dir, VNULL), 0);
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insert_env(format_env("SHELL", runas_pw->pw_shell, VNULL), 0);
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insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), 0);
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insert_env(format_env("USER", runas_pw->pw_name, VNULL), 0);
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} else {
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if (!ISSET(didvar, DID_HOME))
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insert_env(format_env("HOME", user_dir, VNULL), 0);
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if (!ISSET(didvar, DID_SHELL))
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insert_env(format_env("SHELL", sudo_user.pw->pw_shell, VNULL), 0);
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if (!ISSET(didvar, DID_LOGNAME))
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insert_env(format_env("LOGNAME", user_name, VNULL), 0);
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if (!ISSET(didvar, DID_USER))
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insert_env(format_env("USER", user_name, VNULL), 0);
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}
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} else {
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/*
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* Copy envp entries as long as they don't match env_delete or
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* env_check.
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*/
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for (ep = envp; *ep; ep++) {
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okvar = 1;
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/* Skip variables with values beginning with () (bash functions) */
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if ((cp = strchr(*ep, '=')) != NULL) {
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if (strncmp(cp, "=() ", 3) == 0)
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continue;
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}
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/* Skip anything listed in env_delete. */
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for (cur = def_env_delete; cur && okvar; cur = cur->next) {
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len = strlen(cur->value);
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/* Deal with '*' wildcard */
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if (cur->value[len - 1] == '*') {
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len--;
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iswild = 1;
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} else
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iswild = 0;
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if (strncmp(cur->value, *ep, len) == 0 &&
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(iswild || (*ep)[len] == '=')) {
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okvar = 0;
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}
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}
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/* Check certain variables for '%' and '/' characters. */
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for (cur = def_env_check; cur && okvar; cur = cur->next) {
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len = strlen(cur->value);
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/* Deal with '*' wildcard */
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if (cur->value[len - 1] == '*') {
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len--;
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iswild = 1;
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} else
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iswild = 0;
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if (strncmp(cur->value, *ep, len) == 0 &&
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(iswild || (*ep)[len] == '=') &&
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strpbrk(*ep, "/%")) {
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okvar = 0;
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}
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}
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if (okvar) {
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if (strncmp(*ep, "SUDO_PS1=", 9) == 0)
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ps1 = *ep + 5;
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else if (strncmp(*ep, "PATH=", 5) == 0)
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SET(didvar, DID_PATH);
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else if (strncmp(*ep, "TERM=", 5) == 0)
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SET(didvar, DID_TERM);
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insert_env(*ep, 0);
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}
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}
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}
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/* Provide default values for $TERM and $PATH if they are not set. */
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if (!ISSET(didvar, DID_TERM))
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insert_env("TERM=unknown", 0);
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if (!ISSET(didvar, DID_PATH))
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insert_env(format_env("PATH", _PATH_DEFPATH, VNULL), 0);
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/* Replace the PATH envariable with a secure one. */
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if (def_secure_path && !user_is_exempt())
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insert_env(format_env("PATH", def_secure_path, VNULL), 1);
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/* Set $USER and $LOGNAME to target if "set_logname" is true. */
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if (def_set_logname && runas_pw->pw_name) {
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insert_env(format_env("LOGNAME", runas_pw->pw_name, VNULL), 1);
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insert_env(format_env("USER", runas_pw->pw_name, VNULL), 1);
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}
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/* Set $HOME for `sudo -H'. Only valid at PERM_FULL_RUNAS. */
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if (ISSET(sudo_mode, MODE_RESET_HOME) && runas_pw->pw_dir)
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insert_env(format_env("HOME", runas_pw->pw_dir, VNULL), 1);
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/*
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* Preload a noexec file? For a list of LD_PRELOAD-alikes, see
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* http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html
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* XXX - should prepend to original value, if any
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*/
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if (noexec && def_noexec_file != NULL) {
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#if defined(__darwin__) || defined(__APPLE__)
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insert_env(format_env("DYLD_INSERT_LIBRARIES", def_noexec_file, VNULL), 1);
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insert_env(format_env("DYLD_FORCE_FLAT_NAMESPACE", VNULL), 1);
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#else
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# if defined(__osf__) || defined(__sgi)
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insert_env(format_env("_RLD_LIST", def_noexec_file, ":DEFAULT", VNULL), 1);
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# else
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insert_env(format_env("LD_PRELOAD", def_noexec_file, VNULL), 1);
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# endif
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#endif
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}
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/* Set PS1 if SUDO_PS1 is set. */
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if (ps1)
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insert_env(ps1, 1);
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/* Add the SUDO_COMMAND envariable (cmnd + args). */
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if (user_args)
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insert_env(format_env("SUDO_COMMAND", user_cmnd, " ", user_args, VNULL), 1);
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else
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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;
|
|
}
|
|
}
|