1 /* 2 * This was written by Andrew G. Morgan <morgan (at) kernel.org> 3 * 4 * This is a program that is intended to exec a subsequent program. 5 * The purpose of this 'execcap' wrapper is to limit the inheritable 6 * capabilities of the exec()'d program. All environment variables 7 * are inherited. 8 */ 9 10 #include <sys/types.h> 11 #include <errno.h> 12 #include <stdio.h> 13 #include <sys/capability.h> 14 #include <unistd.h> 15 #include <string.h> 16 #include <stdlib.h> 17 18 static void usage(void) 19 { 20 fprintf(stderr, 21 "usage: execcap <caps> <command-path> [command-args...]\n\n" 22 " This program is a wrapper that can be used to limit the Inheritable\n" 23 " capabilities of a program to be executed. Note, this wrapper is\n" 24 " intended to assist in overcoming a lack of support for filesystem\n" 25 " capability attributes and should be used to launch other files.\n" 26 " This program should _NOT_ be made setuid-0.\n\n" 27 "[Copyright (c) 1998 Andrew G. Morgan <morgan (at) kernel.org>]\n"); 28 29 exit(1); 30 } 31 32 int main(int argc, char **argv) 33 { 34 cap_t new_caps; 35 36 /* this program should not be made setuid-0 */ 37 if (getuid() && !geteuid()) { 38 usage(); 39 } 40 41 /* check that we have at least 2 arguments */ 42 if (argc < 3) { 43 usage(); 44 } 45 46 /* parse the first argument to obtain a set of capabilities */ 47 new_caps = cap_from_text(argv[1]); 48 if (new_caps == NULL) { 49 fprintf(stderr, "requested capabilities were not recognized\n"); 50 usage(); 51 } 52 53 /* set these capabilities for the current process */ 54 if (cap_set_proc(new_caps) != 0) { 55 fprintf(stderr, "unable to set capabilities: %s\n", strerror(errno)); 56 usage(); 57 } 58 59 /* exec the program indicated by args 2 ... */ 60 execvp(argv[2], argv+2); 61 62 /* if we fall through to here, our exec failed -- announce the fact */ 63 fprintf(stderr, "Unable to execute command: %s\n", strerror(errno)); 64 65 usage(); 66 67 return 0; 68 } 69
