// 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