diff -r ffa851df0825 -r 2fb8b9db1c86 symbian-qemu-0.9.1-12/python-2.6.1/Misc/setuid-prog.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/symbian-qemu-0.9.1-12/python-2.6.1/Misc/setuid-prog.c Fri Jul 31 15:01:17 2009 +0100 @@ -0,0 +1,176 @@ +/* + Template for a setuid program that calls a script. + + The script should be in an unwritable directory and should itself + be unwritable. In fact all parent directories up to the root + should be unwritable. The script must not be setuid, that's what + this program is for. + + This is a template program. You need to fill in the name of the + script that must be executed. This is done by changing the + definition of FULL_PATH below. + + There are also some rules that should be adhered to when writing + the script itself. + + The first and most important rule is to never, ever trust that the + user of the program will behave properly. Program defensively. + Check your arguments for reasonableness. If the user is allowed to + create files, check the names of the files. If the program depends + on argv[0] for the action it should perform, check it. + + Assuming the script is a Bourne shell script, the first line of the + script should be + #!/bin/sh - + The - is important, don't omit it. If you're using esh, the first + line should be + #!/usr/local/bin/esh -f + and for ksh, the first line should be + #!/usr/local/bin/ksh -p + The script should then set the variable IFS to the string + consisting of , , and . After this (*not* + before!), the PATH variable should be set to a reasonable value and + exported. Do not expect the PATH to have a reasonable value, so do + not trust the old value of PATH. You should then set the umask of + the program by calling + umask 077 # or 022 if you want the files to be readable + If you plan to change directories, you should either unset CDPATH + or set it to a good value. Setting CDPATH to just ``.'' (dot) is a + good idea. + If, for some reason, you want to use csh, the first line should be + #!/bin/csh -fb + You should then set the path variable to something reasonable, + without trusting the inherited path. Here too, you should set the + umask using the command + umask 077 # or 022 if you want the files to be readable +*/ + +#include +#include +#include +#include +#include +#include + +/* CONFIGURATION SECTION */ + +#ifndef FULL_PATH /* so that this can be specified from the Makefile */ +/* Uncomment the following line: +#define FULL_PATH "/full/path/of/script" +* Then comment out the #error line. */ +#error "You must define FULL_PATH somewhere" +#endif +#ifndef UMASK +#define UMASK 077 +#endif + +/* END OF CONFIGURATION SECTION */ + +#if defined(__STDC__) && defined(__sgi) +#define environ _environ +#endif + +/* don't change def_IFS */ +char def_IFS[] = "IFS= \t\n"; +/* you may want to change def_PATH, but you should really change it in */ +/* your script */ +#ifdef __sgi +char def_PATH[] = "PATH=/usr/bsd:/usr/bin:/bin:/usr/local/bin:/usr/sbin"; +#else +char def_PATH[] = "PATH=/usr/ucb:/usr/bin:/bin:/usr/local/bin"; +#endif +/* don't change def_CDPATH */ +char def_CDPATH[] = "CDPATH=."; +/* don't change def_ENV */ +char def_ENV[] = "ENV=:"; + +/* + This function changes all environment variables that start with LD_ + into variables that start with XD_. This is important since we + don't want the script that is executed to use any funny shared + libraries. + + The other changes to the environment are, strictly speaking, not + needed here. They can safely be done in the script. They are done + here because we don't trust the script writer (just like the script + writer shouldn't trust the user of the script). + If IFS is set in the environment, set it to space,tab,newline. + If CDPATH is set in the environment, set it to ``.''. + Set PATH to a reasonable default. +*/ +void +clean_environ(void) +{ + char **p; + extern char **environ; + + for (p = environ; *p; p++) { + if (strncmp(*p, "LD_", 3) == 0) + **p = 'X'; + else if (strncmp(*p, "_RLD", 4) == 0) + **p = 'X'; + else if (strncmp(*p, "PYTHON", 6) == 0) + **p = 'X'; + else if (strncmp(*p, "IFS=", 4) == 0) + *p = def_IFS; + else if (strncmp(*p, "CDPATH=", 7) == 0) + *p = def_CDPATH; + else if (strncmp(*p, "ENV=", 4) == 0) + *p = def_ENV; + } + putenv(def_PATH); +} + +int +main(int argc, char **argv) +{ + struct stat statb; + gid_t egid = getegid(); + uid_t euid = geteuid(); + + /* + Sanity check #1. + This check should be made compile-time, but that's not possible. + If you're sure that you specified a full path name for FULL_PATH, + you can omit this check. + */ + if (FULL_PATH[0] != '/') { + fprintf(stderr, "%s: %s is not a full path name\n", argv[0], + FULL_PATH); + fprintf(stderr, "You can only use this wrapper if you\n"); + fprintf(stderr, "compile it with an absolute path.\n"); + exit(1); + } + + /* + Sanity check #2. + Check that the owner of the script is equal to either the + effective uid or the super user. + */ + if (stat(FULL_PATH, &statb) < 0) { + perror("stat"); + exit(1); + } + if (statb.st_uid != 0 && statb.st_uid != euid) { + fprintf(stderr, "%s: %s has the wrong owner\n", argv[0], + FULL_PATH); + fprintf(stderr, "The script should be owned by root,\n"); + fprintf(stderr, "and shouldn't be writeable by anyone.\n"); + exit(1); + } + + if (setregid(egid, egid) < 0) + perror("setregid"); + if (setreuid(euid, euid) < 0) + perror("setreuid"); + + clean_environ(); + + umask(UMASK); + + while (**argv == '-') /* don't let argv[0] start with '-' */ + (*argv)++; + execv(FULL_PATH, argv); + fprintf(stderr, "%s: could not execute the script\n", argv[0]); + exit(1); +}