mirror of https://gerrit.osmocom.org/asn1c
112 lines
2.0 KiB
C
112 lines
2.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <sysexits.h>
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#ifdef WIN32
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#define setuid(s)
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#define getuid()
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#define setgid(s)
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#define getgid()
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#define chroot(p) (-1)
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#endif
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/*
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* This program chroots into a given directory,
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* then executes the asn1c command with strict arguments checking.
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*/
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int
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main(int ac, char **av) {
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char cmdPath[32];
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char *envp[] = { NULL }; /* Empty environment */
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int ret;
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int i;
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if(ac < 4) {
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setgid(getgid());
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setuid(getuid());
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fprintf(stderr,
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"Usage: %s <chroot-to> <chdir-to> <command> [options]\n",
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av[0]);
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exit(EX_USAGE);
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}
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ret = chroot(av[1]);
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/* Drop the privileges */
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setgid(getgid());
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setuid(getuid());
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if(ret != 0) {
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fprintf(stderr, "chroot(\"%s\") failed: %s\n",
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av[1], strerror(errno));
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exit(EX_OSERR);
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}
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if(chdir(av[2]) != 0) {
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fprintf(stderr, "chdir(\"%s\") failed: %s\n",
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av[2], strerror(errno));
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exit(EX_OSERR);
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}
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if(ac > 64) {
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fprintf(stderr, "Insecure number of arguments: %d\n", ac);
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exit(EX_DATAERR);
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}
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/*
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* Add an argument if this is an asn1c compiler.
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*/
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if(strcmp(av[3], "asn1c") == 0) {
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ac -= 2;
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av += 2;
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av[0] = "asn1c";
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av[1] = "-S/skeletons";
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i = 2;
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strcpy(cmdPath, "/bin/asn1c");
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} else {
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ac -= 3;
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av += 3;
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i = 0;
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}
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if(strlen(av[0]) > sizeof(cmdPath)/2) {
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fprintf(stderr, "Insecure command name: %s\n", av[0]);
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exit(EX_DATAERR);
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}
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memcpy(cmdPath, "/bin/", 5);
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strcpy(cmdPath + 5, av[0]);
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/*
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* Check arguments for the permitted alphabet constraints.
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*/
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for(; i < ac; i++) {
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char *p;
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for(p = av[i];; p++) {
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switch(*p) {
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case '0' ... '9': case 'A' ... 'Z': case 'a' ... 'z':
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case '.': case '_': case '-': case '=':
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continue;
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case '\0':
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default:
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break;
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}
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break;
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}
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if(*p || (p - av[i]) > 250) {
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fprintf(stderr, "Insecure argument %d\n", i);
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exit(EX_DATAERR);
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}
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}
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execve(cmdPath, av, envp);
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perror(cmdPath);
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exit(EX_UNAVAILABLE);
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}
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