471 lines
12 KiB
C
471 lines
12 KiB
C
/*
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* Copyright (c) 2000-2002 Todd C. Miller <Todd.Miller@courtesan.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* 4. Products derived from this software may not be called "Sudo" nor
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* may "Sudo" appear in their names without specific prior written
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* permission from the author.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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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 <errno.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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/*
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* Prototypes
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*/
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char **rebuild_env __P((int, char **));
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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 *, 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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"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
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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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char **ep, **nep;
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static char *newenv[7];
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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 '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))
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user_prompt = *ep + 12;
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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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*nep++ = *ep;
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}
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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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format_env(var, val)
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char *var;
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char *val;
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{
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char *estring, *p;
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size_t varlen, vallen;
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varlen = strlen(var);
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vallen = strlen(val);
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p = estring = (char *) emalloc(varlen + vallen + 2);
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strcpy(p, var);
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p += varlen;
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*p++ = '=';
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strcpy(p, val);
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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. */
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if (env_len + 1 > env_size) {
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env_size += 128;
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new_environ = erealloc(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(sudo_mode, envp)
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int sudo_mode;
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char **envp;
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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_flag(I_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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for (cur = def_list(I_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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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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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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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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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 (!(didvar & DID_TERM) && !strncmp(*ep, "TERM=", 5)) {
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insert_env(*ep, 0);
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didvar |= DID_TERM;
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} else if (!(didvar & DID_PATH) && !strncmp(*ep, "PATH=", 5)) {
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insert_env(*ep, 0);
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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 unless they were preserved from the
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* user's environment.
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*/
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if (!(didvar & DID_HOME))
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insert_env(format_env("HOME", user_dir), 0);
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if (!(didvar & DID_SHELL))
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insert_env(format_env("SHELL", sudo_user.pw->pw_shell), 0);
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if (!(didvar & DID_LOGNAME))
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insert_env(format_env("LOGNAME", user_name), 0);
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if (!(didvar & DID_USER))
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insert_env(format_env("USER", user_name), 0);
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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 anything listed in env_delete. */
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for (cur = def_list(I_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_list(I_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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didvar |= DID_PATH;
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else if (strncmp(*ep, "TERM=", 5) == 0)
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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 (!(didvar & DID_TERM))
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insert_env("TERM=unknown", 0);
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if (!(didvar & DID_PATH))
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insert_env(format_env("PATH", _PATH_DEFPATH), 0);
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#ifdef SECURE_PATH
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/* Replace the PATH envariable with a secure one. */
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insert_env(format_env("PATH", SECURE_PATH), 1);
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#endif
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/* Set $USER and $LOGNAME to target if "set_logname" is true. */
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if (def_flag(I_SET_LOGNAME) && runas_pw->pw_name) {
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insert_env(format_env("LOGNAME", runas_pw->pw_name), 1);
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insert_env(format_env("USER", runas_pw->pw_name), 1);
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}
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/* Set $HOME for `sudo -H'. Only valid at PERM_RUNAS. */
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if ((sudo_mode & MODE_RESET_HOME) && runas_pw->pw_dir)
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insert_env(format_env("HOME", runas_pw->pw_dir), 1);
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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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easprintf(&cp, "SUDO_COMMAND=%s %s", user_cmnd, user_args);
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insert_env(cp, 1);
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} else
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insert_env(format_env("SUDO_COMMAND", user_cmnd), 1);
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/* Add the SUDO_USER, SUDO_UID, SUDO_GID environment variables. */
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insert_env(format_env("SUDO_USER", user_name), 1);
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easprintf(&cp, "SUDO_UID=%ld", (long) user_uid);
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insert_env(cp, 1);
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easprintf(&cp, "SUDO_GID=%ld", (long) user_gid);
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insert_env(cp, 1);
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return(new_environ);
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}
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void
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init_envtables()
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{
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struct list_member *cur;
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const char **p;
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/* Fill in "env_delete" variable. */
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for (p = initial_badenv_table; *p; p++) {
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cur = emalloc(sizeof(struct list_member));
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cur->value = estrdup(*p);
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cur->next = def_list(I_ENV_DELETE);
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def_list(I_ENV_DELETE) = cur;
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}
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/* Fill in "env_check" variable. */
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for (p = initial_checkenv_table; *p; p++) {
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cur = emalloc(sizeof(struct list_member));
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cur->value = estrdup(*p);
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cur->next = def_list(I_ENV_CHECK);
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def_list(I_ENV_CHECK) = cur;
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}
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}
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