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128 lines
3.5 KiB
C
128 lines
3.5 KiB
C
/* Check getcontext and setcontext on the context from makecontext
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with shadow stack.
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Copyright (C) 2018-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <ucontext.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <stdatomic.h>
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#include <x86intrin.h>
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static ucontext_t ctx[5];
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static atomic_int done;
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static void
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__attribute__((noinline, noclone))
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f2 (void)
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{
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printf ("start f2\n");
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done++;
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if (setcontext (&ctx[2]) != 0)
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{
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printf ("%s: setcontext: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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}
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static void
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f1 (void)
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{
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printf ("start f1\n");
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if (getcontext (&ctx[2]) != 0)
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{
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printf ("%s: getcontext: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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if (done)
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exit (EXIT_SUCCESS);
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f2 ();
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}
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static int
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do_test (void)
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{
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char st1[32768];
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puts ("making contexts");
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if (getcontext (&ctx[0]) != 0)
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{
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printf ("%s: getcontext: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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if (getcontext (&ctx[1]) != 0)
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{
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printf ("%s: getcontext: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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ctx[3].uc_stack.ss_sp = st1;
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ctx[3].uc_stack.ss_size = sizeof st1;
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ctx[3].uc_link = &ctx[0];
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makecontext (&ctx[3], (void (*) (void)) f1, 0);
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ctx[1].uc_stack.ss_sp = st1;
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ctx[1].uc_stack.ss_size = sizeof st1;
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ctx[1].uc_link = &ctx[0];
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makecontext (&ctx[1], (void (*) (void)) f1, 0);
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ctx[4].uc_stack.ss_sp = st1;
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ctx[4].uc_stack.ss_size = sizeof st1;
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ctx[4].uc_link = &ctx[0];
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makecontext (&ctx[4], (void (*) (void)) f1, 0);
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/* NB: When shadow stack is enabled, makecontext calls arch_prctl
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with ARCH_CET_ALLOC_SHSTK to allocate a new shadow stack which
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can be unmapped. The base address and size of the new shadow
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stack are returned in __ssp[1] and __ssp[2]. makecontext is
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called for CTX1, CTX3 and CTX4. But only CTX1 is used. New
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shadow stacks are allocated in the order of CTX3, CTX1, CTX4.
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It is very likely that CTX1's shadow stack is placed between
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CTX3 and CTX4. We munmap CTX3's and CTX4's shadow stacks to
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create gaps above and below CTX1's shadow stack. We check
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that setcontext CTX1 works correctly in this case. */
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if (_get_ssp () != 0)
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{
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if (ctx[3].__ssp[1] != 0
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&& munmap ((void *) (uintptr_t) ctx[3].__ssp[1],
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(size_t) ctx[3].__ssp[2]) != 0)
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{
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printf ("%s: munmap: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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if (ctx[4].__ssp[1] != 0
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&& munmap ((void *) (uintptr_t) ctx[4].__ssp[1],
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(size_t) ctx[4].__ssp[2]) != 0)
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{
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printf ("%s: munmap: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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}
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if (setcontext (&ctx[1]) != 0)
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{
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printf ("%s: setcontext: %m\n", __FUNCTION__);
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exit (EXIT_FAILURE);
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}
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exit (EXIT_FAILURE);
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}
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#include <support/test-driver.c>
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