102 lines
1.8 KiB
C
102 lines
1.8 KiB
C
/*
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** This program checks to see if your version of setuid works.
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** Compile it, make it setuid root, and run it as yourself (NOT as
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** root).
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**
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** NOTE: This should work everywhere, but Linux has the ability
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** to use the undocumented setcap() call to make this break.
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**
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** Compilation is trivial -- just "cc t_setuid.c". Make it setuid,
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** root and then execute it as a non-root user.
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*/
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdio.h>
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#ifndef lint
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static char id[] = "@(#)$Id: t_setuid.c,v 8.2.2.1 2000/05/31 00:29:47 gshapiro Exp $";
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#endif /* ! lint */
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static void
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printuids(str, r, e)
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char *str;
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int r, e;
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{
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printf("%s (should be %d/%d): r/euid=%d/%d\n", str, r, e,
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getuid(), geteuid());
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}
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int
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main(argc, argv)
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int argc;
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char **argv;
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{
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int fail = 0;
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uid_t realuid = getuid();
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printuids("initial uids", realuid, 0);
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if (geteuid() != 0)
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{
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printf("SETUP ERROR: re-run setuid root\n");
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exit(1);
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}
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if (getuid() == 0)
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{
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printf("SETUP ERROR: must be run by a non-root user\n");
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exit(1);
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}
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if (setuid(1) < 0)
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printf("setuid(1) failure\n");
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printuids("after setuid(1)", 1, 1);
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if (geteuid() != 1)
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{
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fail++;
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printf("MAYDAY! Wrong effective uid\n");
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}
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if (getuid() != 1)
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{
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fail++;
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printf("MAYDAY! Wrong real uid\n");
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}
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/* do activity here */
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if (setuid(0) == 0)
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{
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fail++;
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printf("MAYDAY! setuid(0) succeeded (should have failed)\n");
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}
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else
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{
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printf("setuid(0) failed (this is correct)\n");
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}
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printuids("after setuid(0)", 1, 1);
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if (geteuid() != 1)
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{
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fail++;
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printf("MAYDAY! Wrong effective uid\n");
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}
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if (getuid() != 1)
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{
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fail++;
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printf("MAYDAY! Wrong real uid\n");
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}
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printf("\n");
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if (fail)
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{
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printf("\nThis system cannot use setuid (maybe use setreuid)\n");
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exit(1);
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}
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printf("\nIt is safe to use setuid on this system\n");
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exit(0);
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}
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