432 lines
12 KiB
C
432 lines
12 KiB
C
/*-
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* Copyright (c) 2001 Robert N. M. Watson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/uio.h>
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#include <sys/ptrace.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <sys/syscall.h>
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#include <sys/wait.h>
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#include <sys/ktrace.h>
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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/*
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* Relevant parts of a process credential.
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*/
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struct cred {
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uid_t cr_euid, cr_ruid, cr_svuid;
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int cr_issetugid;
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};
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/*
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* Description of a scenario.
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*/
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struct scenario {
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struct cred *sc_cred1, *sc_cred2; /* credentials of p1 and p2 */
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int sc_canptrace_errno; /* desired ptrace failure */
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int sc_canktrace_errno; /* desired ktrace failure */
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int sc_cansighup_errno; /* desired SIGHUP failure */
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int sc_cansigsegv_errno; /* desired SIGSEGV failure */
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int sc_cansee_errno; /* desired getprio failure */
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int sc_cansched_errno; /* desired setprio failure */
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char *sc_name; /* test name */
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};
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/*
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* Table of relevant credential combinations.
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*/
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static struct cred creds[] = {
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/* euid ruid svuid issetugid */
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/* 0 */ { 0, 0, 0, 0 }, /* privileged */
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/* 1 */ { 0, 0, 0, 1 }, /* privileged + issetugid */
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/* 2 */ { 1000, 1000, 1000, 0 }, /* unprivileged1 */
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/* 3 */ { 1000, 1000, 1000, 1 }, /* unprivileged1 + issetugid */
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/* 4 */ { 1001, 1001, 1001, 0 }, /* unprivileged2 */
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/* 5 */ { 1001, 1001, 1001, 1 }, /* unprivileged2 + issetugid */
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/* 6 */ { 1000, 0, 0, 0 }, /* daemon1 */
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/* 7 */ { 1000, 0, 0, 1 }, /* daemon1 + issetugid */
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/* 8 */ { 1001, 0, 0, 0 }, /* daemon2 */
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/* 9 */ { 1001, 0, 0, 1 }, /* daemon2 + issetugid */
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/* 10 */{ 0, 1000, 1000, 0 }, /* setuid1 */
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/* 11 */{ 0, 1000, 1000, 1 }, /* setuid1 + issetugid */
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/* 12 */{ 0, 1001, 1001, 0 }, /* setuid2 */
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/* 13 */{ 0, 1001, 1001, 1 }, /* setuid2 + issetugid */
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};
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/*
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* Table of scenarios.
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*/
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static const struct scenario scenarios[] = {
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/* cred1 cred2 ptrace ktrace, sighup sigsegv see sched name */
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/* privileged on privileged */
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{ &creds[0], &creds[0], 0, 0, 0, 0, 0, 0, "0. priv on priv"},
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{ &creds[0], &creds[1], 0, 0, 0, 0, 0, 0, "1. priv on priv"},
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{ &creds[1], &creds[0], 0, 0, 0, 0, 0, 0, "2. priv on priv"},
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{ &creds[1], &creds[1], 0, 0, 0, 0, 0, 0, "3. priv on priv"},
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/* privileged on unprivileged */
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{ &creds[0], &creds[2], 0, 0, 0, 0, 0, 0, "4. priv on unpriv1"},
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{ &creds[0], &creds[3], 0, 0, 0, 0, 0, 0, "5. priv on unpriv1"},
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{ &creds[1], &creds[2], 0, 0, 0, 0, 0, 0, "6. priv on unpriv1"},
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{ &creds[1], &creds[3], 0, 0, 0, 0, 0, 0, "7. priv on unpriv1"},
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/* unprivileged on privileged */
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{ &creds[2], &creds[0], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "8. unpriv1 on priv"},
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{ &creds[2], &creds[1], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "9. unpriv1 on priv"},
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{ &creds[3], &creds[0], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "10. unpriv1 on priv"},
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{ &creds[3], &creds[1], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "11. unpriv1 on priv"},
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/* unprivileged on same unprivileged */
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{ &creds[2], &creds[2], 0, 0, 0, 0, 0, 0, "12. unpriv1 on unpriv1"},
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{ &creds[2], &creds[3], EPERM, EPERM, 0, EPERM, 0, 0, "13. unpriv1 on unpriv1"},
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{ &creds[3], &creds[2], 0, 0, 0, 0, 0, 0, "14. unpriv1 on unpriv1"},
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{ &creds[3], &creds[3], EPERM, EPERM, 0, EPERM, 0, 0, "15. unpriv1 on unpriv1"},
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/* unprivileged on different unprivileged */
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{ &creds[2], &creds[4], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "16. unpriv1 on unpriv2"},
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{ &creds[2], &creds[5], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "17. unpriv1 on unpriv2"},
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{ &creds[3], &creds[4], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "18. unpriv1 on unpriv2"},
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{ &creds[3], &creds[5], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "19. unpriv1 on unpriv2"},
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/* unprivileged on daemon, same */
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{ &creds[2], &creds[6], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "20. unpriv1 on daemon1"},
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{ &creds[2], &creds[7], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "21. unpriv1 on daemon1"},
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{ &creds[3], &creds[6], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "22. unpriv1 on daemon1"},
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{ &creds[3], &creds[7], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "23. unpriv1 on daemon1"},
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/* unprivileged on daemon, different */
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{ &creds[2], &creds[8], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "24. unpriv1 on daemon2"},
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{ &creds[2], &creds[9], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "25. unpriv1 on daemon2"},
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{ &creds[3], &creds[8], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "26. unpriv1 on daemon2"},
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{ &creds[3], &creds[9], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "27. unpriv1 on daemon2"},
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/* unprivileged on setuid, same */
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{ &creds[2], &creds[10], EPERM, EPERM, 0, 0, 0, 0, "28. unpriv1 on setuid1"},
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{ &creds[2], &creds[11], EPERM, EPERM, 0, EPERM, 0, 0, "29. unpriv1 on setuid1"},
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{ &creds[3], &creds[10], EPERM, EPERM, 0, 0, 0, 0, "30. unpriv1 on setuid1"},
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{ &creds[3], &creds[11], EPERM, EPERM, 0, EPERM, 0, 0, "31. unpriv1 on setuid1"},
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/* unprivileged on setuid, different */
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{ &creds[2], &creds[12], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "32. unpriv1 on setuid2"},
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{ &creds[2], &creds[13], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "33. unpriv1 on setuid2"},
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{ &creds[3], &creds[12], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "34. unpriv1 on setuid2"},
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{ &creds[3], &creds[13], EPERM, EPERM, EPERM, EPERM, 0, EPERM, "35. unpriv1 on setuid2"},
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};
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int scenarios_count = sizeof(scenarios) / sizeof(struct scenario);
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/*
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* Convert an error number to a compact string representation. For now,
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* implement only the error numbers we are likely to see.
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*/
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static char *
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errno_to_string(int error)
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{
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switch (error) {
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case EPERM:
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return ("EPERM");
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case EACCES:
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return ("EACCES");
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case EINVAL:
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return ("EINVAL");
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case ENOSYS:
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return ("ENOSYS");
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case ESRCH:
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return ("ESRCH");
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case EOPNOTSUPP:
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return ("EOPNOTSUPP");
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case 0:
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return ("0");
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default:
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printf("%d\n", error);
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return ("unknown");
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}
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}
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/*
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* Return a process credential describing the current process.
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*/
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static int
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cred_get(struct cred *cred)
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{
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int error;
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error = getresuid(&cred->cr_ruid, &cred->cr_euid, &cred->cr_svuid);
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if (error)
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return (error);
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cred->cr_issetugid = issetugid();
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return (0);
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}
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/*
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* Userland stub for __setsugid() to take into account possible presence
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* in C library, kernel, et al.
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*/
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int
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setugid(int flag)
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{
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#ifdef SETSUGID_SUPPORTED
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return (__setugid(flag));
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#else
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#ifdef SETSUGID_SUPPORTED_BUT_NO_LIBC_STUB
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return (syscall(374, flag));
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#else
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return (ENOSYS);
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#endif
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#endif
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}
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/*
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* Set the current process's credentials to match the passed credential.
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*/
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static int
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cred_set(struct cred *cred)
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{
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int error;
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error = setresuid(cred->cr_ruid, cred->cr_euid, cred->cr_svuid);
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if (error)
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return (error);
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error = setugid(cred->cr_issetugid);
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if (error) {
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perror("__setugid");
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return (error);
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}
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#ifdef CHECK_CRED_SET
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{
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uid_t ruid, euid, svuid;
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error = getresuid(&ruid, &euid, &svuid);
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if (error) {
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perror("getresuid");
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return (-1);
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}
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assert(ruid == cred->cr_ruid);
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assert(euid == cred->cr_euid);
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assert(svuid == cred->cr_svuid);
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assert(cred->cr_issetugid == issetugid());
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}
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#endif /* !CHECK_CRED_SET */
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return (0);
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}
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/*
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* Print the passed process credential to the passed I/O stream.
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*/
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static void
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cred_print(FILE *output, struct cred *cred)
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{
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fprintf(output, "(e:%d r:%d s:%d P_SUGID:%d)", cred->cr_euid,
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cred->cr_ruid, cred->cr_svuid, cred->cr_issetugid);
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}
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#define LOOP_PTRACE 0
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#define LOOP_KTRACE 1
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#define LOOP_SIGHUP 2
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#define LOOP_SIGSEGV 3
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#define LOOP_SEE 4
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#define LOOP_SCHED 5
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#define LOOP_MAX LOOP_SCHED
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/*
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* Enact a scenario by looping through the four test cases for the scenario,
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* spawning off pairs of processes with the desired credentials, and
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* reporting results to stdout.
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*/
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static int
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enact_scenario(int scenario)
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{
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pid_t pid1, pid2;
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char *name, *tracefile;
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int error, desirederror, loop;
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for (loop = 0; loop < LOOP_MAX+1; loop++) {
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/*
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* Spawn the first child, target of the operation.
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*/
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pid1 = fork();
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switch (pid1) {
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case -1:
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return (-1);
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case 0:
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/* child */
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error = cred_set(scenarios[scenario].sc_cred2);
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if (error) {
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perror("cred_set");
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return (error);
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}
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/* 200 seconds should be plenty of time. */
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sleep(200);
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exit(0);
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default:
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/* parent */
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}
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/*
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* XXX
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* This really isn't ideal -- give proc 1 a chance to set
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* its credentials, or we may get spurious errors. Really,
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* some for of IPC should be used to allow the parent to
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* wait for the first child to be ready before spawning
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* the second child.
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*/
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sleep(1);
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/*
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* Spawn the second child, source of the operation.
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*/
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pid2 = fork();
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switch (pid2) {
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case -1:
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return (-1);
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case 0:
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/* child */
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error = cred_set(scenarios[scenario].sc_cred1);
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if (error) {
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perror("cred_set");
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return (error);
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}
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/*
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* Initialize errno to zero so as to catch any
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* generated errors. In each case, perform the
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* operation. Preserve the error number for later
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* use so it doesn't get stomped on by any I/O.
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* Determine the desired error for the given case
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* by extracting it from the scenario table.
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* Initialize a function name string for output
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* prettiness.
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*/
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errno = 0;
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switch (loop) {
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case LOOP_PTRACE:
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error = ptrace(PT_ATTACH, pid1, NULL, 0);
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error = errno;
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name = "ptrace";
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desirederror =
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scenarios[scenario].sc_canptrace_errno;
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break;
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case LOOP_KTRACE:
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tracefile = mktemp("/tmp/testuid_ktrace.XXXXXX");
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if (tracefile == NULL) {
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error = errno;
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perror("mktemp");
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break;
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}
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error = ktrace(tracefile, KTROP_SET,
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KTRFAC_SYSCALL, pid1);
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error = errno;
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name = "ktrace";
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desirederror =
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scenarios[scenario].sc_canktrace_errno;
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unlink(tracefile);
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break;
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case LOOP_SIGHUP:
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error = kill(pid1, SIGHUP);
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error = errno;
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name = "sighup";
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desirederror =
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scenarios[scenario].sc_cansighup_errno;
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break;
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case LOOP_SIGSEGV:
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error = kill(pid1, SIGSEGV);
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error = errno;
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name = "sigsegv";
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desirederror =
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scenarios[scenario].sc_cansigsegv_errno;
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break;
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case LOOP_SEE:
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getpriority(PRIO_PROCESS, pid1);
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error = errno;
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name = "see";
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desirederror =
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scenarios[scenario].sc_cansee_errno;
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break;
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case LOOP_SCHED:
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error = setpriority(PRIO_PROCESS, pid1,
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0);
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error = errno;
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name = "sched";
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desirederror =
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scenarios[scenario].sc_cansched_errno;
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break;
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default:
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name = "broken";
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}
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if (error != desirederror) {
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fprintf(stdout,
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"[%s].%s: expected %s, got %s\n ",
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scenarios[scenario].sc_name, name,
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errno_to_string(desirederror),
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errno_to_string(error));
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cred_print(stdout,
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scenarios[scenario].sc_cred1);
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cred_print(stdout,
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scenarios[scenario].sc_cred2);
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fprintf(stdout, "\n");
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}
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exit(0);
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default:
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/* parent */
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}
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error = waitpid(pid2, NULL, 0);
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/*
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* Once pid2 has died, it's safe to kill pid1, if it's still
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* alive. Mask signal failure in case the test actually
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* killed pid1 (not unlikely: can occur in both signal and
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* ptrace cases).
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*/
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kill(pid1, SIGKILL);
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error = waitpid(pid2, NULL, 0);
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}
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return (0);
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}
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void
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enact_scenarios(void)
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{
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int i, error;
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for (i = 0; i < scenarios_count; i++) {
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error = enact_scenario(i);
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if (error)
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perror("enact_scenario");
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}
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}
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