181 lines
4.6 KiB
C
181 lines
4.6 KiB
C
/*
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* Copyright 2021 Simon McVittie
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* SPDX-License-Identifier: LGPL-2.0-or-later
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*
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* Try one or more system calls that might have been blocked by a
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* seccomp filter. Return the last value of errno seen.
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*
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* In general, we pass a bad fd or pointer to each syscall that will
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* accept one, so that it will fail with EBADF or EFAULT without side-effects.
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*
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* This helper is used for regression tests in both bubblewrap and flatpak.
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* Please keep both copies in sync.
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*/
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#include <errno.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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#include <sys/ioctl.h>
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#include <sys/prctl.h>
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#include <sys/socket.h>
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#include <sys/syscall.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#if defined(_MIPS_SIM)
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# if _MIPS_SIM == _ABIO32
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# define MISSING_SYSCALL_BASE 4000
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# elif _MIPS_SIM == _ABI64
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# define MISSING_SYSCALL_BASE 5000
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# elif _MIPS_SIM == _ABIN32
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# define MISSING_SYSCALL_BASE 6000
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# else
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# error "Unknown MIPS ABI"
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# endif
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#endif
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#if defined(__ia64__)
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# define MISSING_SYSCALL_BASE 1024
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#endif
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#if defined(__alpha__)
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# define MISSING_SYSCALL_BASE 110
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#endif
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#if defined(__x86_64__) && defined(__ILP32__)
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# define MISSING_SYSCALL_BASE 0x40000000
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#endif
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/*
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* MISSING_SYSCALL_BASE:
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*
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* Number to add to the syscall numbers of recently-added syscalls
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* to get the appropriate syscall for the current ABI.
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*/
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#ifndef MISSING_SYSCALL_BASE
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# define MISSING_SYSCALL_BASE 0
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#endif
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#ifndef __NR_clone3
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# define __NR_clone3 (MISSING_SYSCALL_BASE + 435)
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#endif
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/*
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* The size of clone3's parameter (as of 2021)
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*/
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#define SIZEOF_STRUCT_CLONE_ARGS ((size_t) 88)
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/*
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* An invalid pointer that will cause syscalls to fail with EFAULT
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*/
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#define WRONG_POINTER ((char *) 1)
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#ifndef PR_GET_CHILD_SUBREAPER
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#define PR_GET_CHILD_SUBREAPER 37
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#endif
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int
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main (int argc, char **argv)
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{
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int errsv = 0;
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int i;
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for (i = 1; i < argc; i++)
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{
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const char *arg = argv[i];
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if (strcmp (arg, "print-errno-values") == 0)
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{
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printf ("EBADF=%d\n", EBADF);
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printf ("EFAULT=%d\n", EFAULT);
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printf ("ENOENT=%d\n", ENOENT);
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printf ("ENOSYS=%d\n", ENOSYS);
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printf ("EPERM=%d\n", EPERM);
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}
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else if (strcmp (arg, "chmod") == 0)
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{
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/* If not blocked by seccomp, this will fail with EFAULT */
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if (chmod (WRONG_POINTER, 0700) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else if (strcmp (arg, "chroot") == 0)
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{
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/* If not blocked by seccomp, this will fail with EFAULT */
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if (chroot (WRONG_POINTER) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else if (strcmp (arg, "clone3") == 0)
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{
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/* If not blocked by seccomp, this will fail with EFAULT */
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if (syscall (__NR_clone3, WRONG_POINTER, SIZEOF_STRUCT_CLONE_ARGS) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else if (strcmp (arg, "ioctl TIOCNOTTY") == 0)
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{
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/* If not blocked by seccomp, this will fail with EBADF */
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if (ioctl (-1, TIOCNOTTY) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else if (strcmp (arg, "ioctl TIOCSTI") == 0)
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{
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/* If not blocked by seccomp, this will fail with EBADF */
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if (ioctl (-1, TIOCSTI, WRONG_POINTER) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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#ifdef __LP64__
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else if (strcmp (arg, "ioctl TIOCSTI CVE-2019-10063") == 0)
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{
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unsigned long not_TIOCSTI = (0x123UL << 32) | (unsigned long) TIOCSTI;
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/* If not blocked by seccomp, this will fail with EBADF */
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if (syscall (__NR_ioctl, -1, not_TIOCSTI, WRONG_POINTER) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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#endif
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else if (strcmp (arg, "listen") == 0)
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{
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/* If not blocked by seccomp, this will fail with EBADF */
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if (listen (-1, 42) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else if (strcmp (arg, "prctl") == 0)
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{
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/* If not blocked by seccomp, this will fail with EFAULT */
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if (prctl (PR_GET_CHILD_SUBREAPER, WRONG_POINTER, 0, 0, 0) != 0)
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{
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errsv = errno;
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perror (arg);
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}
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}
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else
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{
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fprintf (stderr, "Unsupported syscall \"%s\"\n", arg);
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errsv = ENOENT;
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}
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}
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return errsv;
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}
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