106 lines
4.4 KiB
C
106 lines
4.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ 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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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/safemacros.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/ucontext.h"
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#include "libc/runtime/buffer.h"
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#include "libc/runtime/runtime.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/fileno.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/testlib/testlib.h"
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#include "libc/x/x.h"
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#include "third_party/xed/x86.h"
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char *p;
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bool segfaulted_;
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struct GuardedBuffer b_;
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struct sigaction oldsegv_;
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struct XedDecodedInst xedd_;
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void RestrictPage(void *addr, unsigned flags) {
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addr = (void *)rounddown((intptr_t)addr, PAGESIZE);
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EXPECT_NE(-1, mprotect(addr, PAGESIZE, flags));
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}
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void OnSegLol(int sig, struct siginfo *si, struct ucontext *uc) {
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size_t i;
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uint8_t *rip;
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segfaulted_ = true;
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rip = (uint8_t *)uc->uc_mcontext.rip;
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RestrictPage(rip, PROT_READ | PROT_WRITE | PROT_EXEC);
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ASSERT_EQ(XED_ERROR_NONE,
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xed_instruction_length_decode(xed_decoded_inst_zero_set_mode(
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&xedd_, XED_MACHINE_MODE_LONG_64),
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rip, XED_MAX_INSTRUCTION_BYTES));
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for (i = 0; i < xedd_.decoded_length; ++i) rip[i] = 0x90; /* NOP */
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RestrictPage(rip, PROT_READ | PROT_EXEC);
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}
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void SetUp(void) {
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segfaulted_ = false;
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memset(&b_, 0, sizeof(b_));
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ASSERT_NE(-1, xsigaction(SIGSEGV, OnSegLol, SA_RESETHAND | SA_RESTART, 0,
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&oldsegv_));
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}
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void TearDown(void) {
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EXPECT_NE(-1, sigaction(SIGSEGV, &oldsegv_, NULL));
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bfree(&b_);
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EXPECT_EQ(NULL, b_.p);
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}
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TEST(balloc, createsGuardPage) {
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ASSERT_NE(NULL, (p = balloc(&b_, 1, 1)));
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EXPECT_EQ(p, b_.p);
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p[0] = '.';
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ASSERT_FALSE(segfaulted_);
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/* TODO(jart): fix me!!! */
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/* p[1 + __BIGGEST_ALIGNMENT__] = '!'; */
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/* EXPECT_TRUE(segfaulted_); */
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}
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TEST(balloc, aligned_roundsUp) {
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ASSERT_NE(NULL, (p = balloc(&b_, 128, 1)));
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EXPECT_EQ(0, (intptr_t)b_.p & 127);
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p[127] = '.';
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ASSERT_FALSE(segfaulted_);
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/* TODO(jart): fix me!!! */
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/* p[128 + __BIGGEST_ALIGNMENT__] = '!'; */
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/* EXPECT_TRUE(segfaulted_); */
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}
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TEST(balloc, multipleCalls_avoidsNeedlessSyscalls) {
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size_t c;
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c = g_syscount;
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ASSERT_NE(NULL, (p = balloc(&b_, 1, 31337)));
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EXPECT_GT(g_syscount, c);
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c = g_syscount;
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ASSERT_NE(NULL, (p = balloc(&b_, 1, 31337 / 2)));
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EXPECT_EQ(g_syscount, c);
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c = g_syscount;
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ASSERT_NE(NULL, (p = balloc(&b_, 1, 31337 * 2)));
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EXPECT_GT(g_syscount, c);
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}
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