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/* python-setuid.c - Wrapper for execution of Python setuid scripts |
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* Copyright (C) 2003 Domenico Andreoli |
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* |
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* python-setuid.c is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* python-setuid.c is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with Prua; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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#ifndef PYTHON |
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#error "This wrapper requires PYTHON macro be defined to specify which Python interpreter is to be used." |
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#endif |
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#ifndef FULLPATH |
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#error "This wrapper requires FULLPATH macro be defined to specify which Python script is to be wrapped." |
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#endif |
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|
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#include <unistd.h> |
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#include <stdlib.h> |
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#include <stdio.h> |
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#include <sys/stat.h> |
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#include <sys/resource.h> |
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#include <string.h> |
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#include <stdarg.h> |
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#include <errno.h> |
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|
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#if defined(__STDC__) && defined(__sgi) |
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#define environ _environ |
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#endif |
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|
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static char python[] = PYTHON; |
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static char fullpath[] = FULLPATH; |
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|
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static char def_IFS[] = "IFS= \t\n"; |
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static char def_CDPATH[] = "CDPATH=."; |
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static char def_ENV[] = "ENV=:"; |
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static char def_PATH[] = "PATH=/usr/bin:/bin"; /* :/usr/bin/local"; */ |
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|
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static void die(const char *fmt, ...) |
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{ |
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va_list ap; |
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va_start(ap, fmt); |
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vfprintf(stderr, fmt, ap); |
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va_end(ap); |
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exit(1); |
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} |
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|
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/* |
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* This function changes all environment variables that start with LD_ |
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* into variables that start with XD_. This is important since we |
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* don't want the script that is executed to use any funny shared |
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* libraries. |
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* |
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* If IFS is set in the environment, set it to space,tab,newline. |
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* If CDPATH is set in the environment, set it to ".". |
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* Set PATH to a reasonable default. |
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*/ |
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static void clean_environ(void) |
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{ |
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char **p; |
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extern char **environ; |
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|
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for(p = environ; *p; p++) { |
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if(strncmp(*p, "LD_", 3) == 0) |
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**p = 'X'; |
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else if(strncmp(*p, "_RLD", 4) == 0) |
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**p = 'X'; |
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else if(strncmp(*p, "PYTHON", 6) == 0) |
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**p = 'X'; |
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else if(strncmp(*p, "IFS=", 4) == 0) |
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*p = def_IFS; |
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else if(strncmp(*p, "CDPATH=", 7) == 0) |
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*p = def_CDPATH; |
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else if(strncmp(*p, "ENV=", 4) == 0) |
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*p = def_ENV; |
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} |
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putenv(def_PATH); |
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} |
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|
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int main(int argc, char *argv[]) |
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{ |
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int i; |
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char **args, **a; |
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|
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struct stat statb; |
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struct rlimit rlim; |
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|
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const gid_t egid = getegid(); |
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const uid_t euid = geteuid(); |
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|
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args = (char**) malloc((argc+3) * sizeof(char*)); |
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if(args == NULL) |
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die("%s: malloc: %s\n", argv[0], strerror(errno)); |
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|
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a = args; |
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*(a++) = python; |
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|
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if(euid != getuid() || egid != getgid()) { |
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if(fullpath[0] != '/') |
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die("%s: not a full path name: %s\n", argv[0], fullpath); |
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|
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if(stat(fullpath, &statb) < 0) |
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die("%s: stat: %s\n", argv[0], strerror(errno)); |
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if(statb.st_uid != 0 && statb.st_uid != euid) |
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die("%s: wrong owner: %s\n", argv[0], fullpath); |
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|
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clean_environ(); |
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|
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umask(077); |
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|
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rlim.rlim_cur = 0; |
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rlim.rlim_max = 0; |
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if(setrlimit(RLIMIT_CORE, &rlim) < 0) |
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die("%s: setrlimit: %s\n", argv[0], strerror(errno)); |
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|
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#ifdef PYTHON_VERSION |
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/* the -E switch has been added in version 2.2 */ |
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if(strcmp(PYTHON_VERSION, "2.2") >= 0) { |
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/* this should be superfluous given the castrated environment */ |
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*(a++) = "-E"; |
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} |
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#endif |
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} |
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|
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*(a++) = fullpath; |
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|
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for(i = 1; argv[i] != NULL; i++) |
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*(a++) = argv[i]; |
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|
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*a = NULL; |
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|
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execv(python, args); |
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|
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die("%s: unable to execute %s: %s\n", argv[0], fullpath, strerror(errno)); |
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|
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return 1; |
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} |