// SPDX-License-Identifier: GPL-2.0
#ifdef __aarch64__
#include <asm/hwcap.h>
#endif
#include <linux/mman.h>
#include <linux/prctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/auxv.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>
#include "../kselftest_harness.h"
#ifndef __aarch64__
# define PROT_BTI 0
#endif
TEST(prctl_flags)
{
EXPECT_LT(prctl(PR_SET_MDWE, PR_MDWE_NO_INHERIT, 0L, 0L, 7L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 7L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 0L, 7L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_GET_MDWE, 7L, 0L, 0L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_GET_MDWE, 0L, 7L, 0L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 7L, 0L), 0);
EXPECT_EQ(errno, EINVAL);
EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0);
EXPECT_EQ(errno, EINVAL);
}
FIXTURE(consecutive_prctl_flags) {};
FIXTURE_SETUP(consecutive_prctl_flags) {}
FIXTURE_TEARDOWN(consecutive_prctl_flags) {}
FIXTURE_VARIANT(consecutive_prctl_flags)
{
unsigned long first_flags;
unsigned long second_flags;
bool should_work;
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_no_flags)
{
.first_flags = 0,
.second_flags = 0,
.should_work = true,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_exec_gain)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
.second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
.should_work = true,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_both_flags)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
.second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
.should_work = true,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
.second_flags = 0,
.should_work = false,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe_no_inherit)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
.second_flags = 0,
.should_work = false,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_no_inherit)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
.second_flags = PR_MDWE_REFUSE_EXEC_GAIN,
.should_work = false,
};
FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_enable_no_inherit)
{
.first_flags = PR_MDWE_REFUSE_EXEC_GAIN,
.second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT,
.should_work = false,
};
TEST_F(consecutive_prctl_flags, two_prctls)
{
int ret;
EXPECT_EQ(prctl(PR_SET_MDWE, variant->first_flags, 0L, 0L, 0L), 0);
ret = prctl(PR_SET_MDWE, variant->second_flags, 0L, 0L, 0L);
if (variant->should_work) {
EXPECT_EQ(ret, 0);
ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L);
ASSERT_EQ(ret, variant->second_flags);
} else {
EXPECT_NE(ret, 0);
ASSERT_EQ(errno, EPERM);
}
}
FIXTURE(mdwe)
{
void *p;
int flags;
size_t size;
pid_t pid;
};
FIXTURE_VARIANT(mdwe)
{
bool enabled;
bool forked;
bool inherit;
};
FIXTURE_VARIANT_ADD(mdwe, stock)
{
.enabled = false,
.forked = false,
.inherit = false,
};
FIXTURE_VARIANT_ADD(mdwe, enabled)
{
.enabled = true,
.forked = false,
.inherit = true,
};
FIXTURE_VARIANT_ADD(mdwe, inherited)
{
.enabled = true,
.forked = true,
.inherit = true,
};
FIXTURE_VARIANT_ADD(mdwe, not_inherited)
{
.enabled = true,
.forked = true,
.inherit = false,
};
static bool executable_map_should_fail(const FIXTURE_VARIANT(mdwe) *variant)
{
return variant->enabled && (!variant->forked || variant->inherit);
}
FIXTURE_SETUP(mdwe)
{
unsigned long mdwe_flags;
int ret, status;
self->p = NULL;
self->flags = MAP_SHARED | MAP_ANONYMOUS;
self->size = getpagesize();
if (!variant->enabled)
return;
mdwe_flags = PR_MDWE_REFUSE_EXEC_GAIN;
if (!variant->inherit)
mdwe_flags |= PR_MDWE_NO_INHERIT;
ret = prctl(PR_SET_MDWE, mdwe_flags, 0L, 0L, 0L);
ASSERT_EQ(ret, 0) {
TH_LOG("PR_SET_MDWE failed or unsupported");
}
ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L);
ASSERT_EQ(ret, mdwe_flags);
if (variant->forked) {
self->pid = fork();
ASSERT_GE(self->pid, 0) {
TH_LOG("fork failed\n");
}
if (self->pid > 0) {
ret = waitpid(self->pid, &status, 0);
ASSERT_TRUE(WIFEXITED(status));
exit(WEXITSTATUS(status));
}
}
}
FIXTURE_TEARDOWN(mdwe)
{
if (self->p && self->p != MAP_FAILED)
munmap(self->p, self->size);
}
TEST_F(mdwe, mmap_READ_EXEC)
{
self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
EXPECT_NE(self->p, MAP_FAILED);
}
TEST_F(mdwe, mmap_WRITE_EXEC)
{
self->p = mmap(NULL, self->size, PROT_WRITE | PROT_EXEC, self->flags, 0, 0);
if (executable_map_should_fail(variant)) {
EXPECT_EQ(self->p, MAP_FAILED);
} else {
EXPECT_NE(self->p, MAP_FAILED);
}
}
TEST_F(mdwe, mprotect_stay_EXEC)
{
int ret;
self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC);
EXPECT_EQ(ret, 0);
}
TEST_F(mdwe, mprotect_add_EXEC)
{
int ret;
self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC);
if (executable_map_should_fail(variant)) {
EXPECT_LT(ret, 0);
} else {
EXPECT_EQ(ret, 0);
}
}
TEST_F(mdwe, mprotect_WRITE_EXEC)
{
int ret;
self->p = mmap(NULL, self->size, PROT_WRITE, self->flags, 0, 0);
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_WRITE | PROT_EXEC);
if (executable_map_should_fail(variant)) {
EXPECT_LT(ret, 0);
} else {
EXPECT_EQ(ret, 0);
}
}
TEST_F(mdwe, mmap_FIXED)
{
void *p;
self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
ASSERT_NE(self->p, MAP_FAILED);
/* MAP_FIXED unmaps the existing page before mapping which is allowed */
p = mmap(self->p, self->size, PROT_READ | PROT_EXEC,
self->flags | MAP_FIXED, 0, 0);
EXPECT_EQ(p, self->p);
}
TEST_F(mdwe, arm64_BTI)
{
int ret;
#ifdef __aarch64__
if (!(getauxval(AT_HWCAP2) & HWCAP2_BTI))
#endif
SKIP(return, "HWCAP2_BTI not supported");
self->p = mmap(NULL, self->size, PROT_EXEC, self->flags, 0, 0);
ASSERT_NE(self->p, MAP_FAILED);
ret = mprotect(self->p, self->size, PROT_EXEC | PROT_BTI);
EXPECT_EQ(ret, 0);
}
TEST_HARNESS_MAIN