Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

[cris-mirror.git] / tools / testing / selftests / x86 / protection_keys.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Tests x86 Memory Protection Keys (see Documentation/x86/protection-keys.txt)
 *
 * There are examples in here of:
 *  * how to set protection keys on memory
 *  * how to set/clear bits in PKRU (the rights register)
 *  * how to handle SEGV_PKRU signals and extract pkey-relevant
 *    information from the siginfo
 *
 * Things to add:
 *      make sure KSM and KSM COW breaking works
 *      prefault pages in at malloc, or not
 *      protect MPX bounds tables with protection keys?
 *      make sure VMA splitting/merging is working correctly
 *      OOMs can destroy mm->mmap (see exit_mmap()), so make sure it is immune to pkeys
 *      look for pkey "leaks" where it is still set on a VMA but "freed" back to the kernel
 *      do a plain mprotect() to a mprotect_pkey() area and make sure the pkey sticks
 *
 * Compile like this:
 *      gcc      -o protection_keys    -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm
 *      gcc -m32 -o protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm
 */
#define _GNU_SOURCE
#include <errno.h>
#include <linux/futex.h>
#include <sys/time.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <signal.h>
#include <assert.h>
#include <stdlib.h>
#include <ucontext.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <setjmp.h>

#include "pkey-helpers.h"

int iteration_nr = 1;
int test_nr;

unsigned int shadow_pkru;

#define HPAGE_SIZE      (1UL<<21)
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
#define ALIGN_UP(x, align_to)   (((x) + ((align_to)-1)) & ~((align_to)-1))
#define ALIGN_DOWN(x, align_to) ((x) & ~((align_to)-1))
#define ALIGN_PTR_UP(p, ptr_align_to)   ((typeof(p))ALIGN_UP((unsigned long)(p),        ptr_align_to))
#define ALIGN_PTR_DOWN(p, ptr_align_to) ((typeof(p))ALIGN_DOWN((unsigned long)(p),      ptr_align_to))
#define __stringify_1(x...)     #x
#define __stringify(x...)       __stringify_1(x)

#define PTR_ERR_ENOTSUP ((void *)-ENOTSUP)

int dprint_in_signal;
char dprint_in_signal_buffer[DPRINT_IN_SIGNAL_BUF_SIZE];

extern void abort_hooks(void);
#define pkey_assert(condition) do {             \
        if (!(condition)) {                     \
                dprintf0("assert() at %s::%d test_nr: %d iteration: %d\n", \
                                __FILE__, __LINE__,     \
                                test_nr, iteration_nr); \
                dprintf0("errno at assert: %d", errno); \
                abort_hooks();                  \
                assert(condition);              \
        }                                       \
} while (0)
#define raw_assert(cond) assert(cond)

void cat_into_file(char *str, char *file)
{
        int fd = open(file, O_RDWR);
        int ret;

        dprintf2("%s(): writing '%s' to '%s'\n", __func__, str, file);
        /*
         * these need to be raw because they are called under
         * pkey_assert()
         */
        raw_assert(fd >= 0);
        ret = write(fd, str, strlen(str));
        if (ret != strlen(str)) {
                perror("write to file failed");
                fprintf(stderr, "filename: '%s' str: '%s'\n", file, str);
                raw_assert(0);
        }
        close(fd);
}

#if CONTROL_TRACING > 0
static int warned_tracing;
int tracing_root_ok(void)
{
        if (geteuid() != 0) {
                if (!warned_tracing)
                        fprintf(stderr, "WARNING: not run as root, "
                                        "can not do tracing control\n");
                warned_tracing = 1;
                return 0;
        }
        return 1;
}
#endif

void tracing_on(void)
{
#if CONTROL_TRACING > 0
#define TRACEDIR "/sys/kernel/debug/tracing"
        char pidstr[32];

        if (!tracing_root_ok())
                return;

        sprintf(pidstr, "%d", getpid());
        cat_into_file("0", TRACEDIR "/tracing_on");
        cat_into_file("\n", TRACEDIR "/trace");
        if (1) {
                cat_into_file("function_graph", TRACEDIR "/current_tracer");
                cat_into_file("1", TRACEDIR "/options/funcgraph-proc");
        } else {
                cat_into_file("nop", TRACEDIR "/current_tracer");
        }
        cat_into_file(pidstr, TRACEDIR "/set_ftrace_pid");
        cat_into_file("1", TRACEDIR "/tracing_on");
        dprintf1("enabled tracing\n");
#endif
}

void tracing_off(void)
{
#if CONTROL_TRACING > 0
        if (!tracing_root_ok())
                return;
        cat_into_file("0", "/sys/kernel/debug/tracing/tracing_on");
#endif
}

void abort_hooks(void)
{
        fprintf(stderr, "running %s()...\n", __func__);
        tracing_off();
#ifdef SLEEP_ON_ABORT
        sleep(SLEEP_ON_ABORT);
#endif
}

static inline void __page_o_noops(void)
{
        /* 8-bytes of instruction * 512 bytes = 1 page */
        asm(".rept 512 ; nopl 0x7eeeeeee(%eax) ; .endr");
}

/*
 * This attempts to have roughly a page of instructions followed by a few
 * instructions that do a write, and another page of instructions.  That
 * way, we are pretty sure that the write is in the second page of
 * instructions and has at least a page of padding behind it.
 *
 * *That* lets us be sure to madvise() away the write instruction, which
 * will then fault, which makes sure that the fault code handles
 * execute-only memory properly.
 */
__attribute__((__aligned__(PAGE_SIZE)))
void lots_o_noops_around_write(int *write_to_me)
{
        dprintf3("running %s()\n", __func__);
        __page_o_noops();
        /* Assume this happens in the second page of instructions: */
        *write_to_me = __LINE__;
        /* pad out by another page: */
        __page_o_noops();
        dprintf3("%s() done\n", __func__);
}

/* Define some kernel-like types */
#define  u8 uint8_t
#define u16 uint16_t
#define u32 uint32_t
#define u64 uint64_t

#ifdef __i386__

#ifndef SYS_mprotect_key
# define SYS_mprotect_key 380
#endif
#ifndef SYS_pkey_alloc
# define SYS_pkey_alloc  381
# define SYS_pkey_free   382
#endif
#define REG_IP_IDX REG_EIP
#define si_pkey_offset 0x14

#else

#ifndef SYS_mprotect_key
# define SYS_mprotect_key 329
#endif
#ifndef SYS_pkey_alloc
# define SYS_pkey_alloc  330
# define SYS_pkey_free   331
#endif
#define REG_IP_IDX REG_RIP
#define si_pkey_offset 0x20

#endif

void dump_mem(void *dumpme, int len_bytes)
{
        char *c = (void *)dumpme;
        int i;

        for (i = 0; i < len_bytes; i += sizeof(u64)) {
                u64 *ptr = (u64 *)(c + i);
                dprintf1("dump[%03d][@%p]: %016jx\n", i, ptr, *ptr);
        }
}

#define SEGV_BNDERR     3  /* failed address bound checks */
#define SEGV_PKUERR     4

static char *si_code_str(int si_code)
{
        if (si_code == SEGV_MAPERR)
                return "SEGV_MAPERR";
        if (si_code == SEGV_ACCERR)
                return "SEGV_ACCERR";
        if (si_code == SEGV_BNDERR)
                return "SEGV_BNDERR";
        if (si_code == SEGV_PKUERR)
                return "SEGV_PKUERR";
        return "UNKNOWN";
}

int pkru_faults;
int last_si_pkey = -1;
void signal_handler(int signum, siginfo_t *si, void *vucontext)
{
        ucontext_t *uctxt = vucontext;
        int trapno;
        unsigned long ip;
        char *fpregs;
        u32 *pkru_ptr;
        u64 siginfo_pkey;
        u32 *si_pkey_ptr;
        int pkru_offset;
        fpregset_t fpregset;

        dprint_in_signal = 1;
        dprintf1(">>>>===============SIGSEGV============================\n");
        dprintf1("%s()::%d, pkru: 0x%x shadow: %x\n", __func__, __LINE__,
                        __rdpkru(), shadow_pkru);

        trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
        ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
        fpregset = uctxt->uc_mcontext.fpregs;
        fpregs = (void *)fpregset;

        dprintf2("%s() trapno: %d ip: 0x%lx info->si_code: %s/%d\n", __func__,
                        trapno, ip, si_code_str(si->si_code), si->si_code);
#ifdef __i386__
        /*
         * 32-bit has some extra padding so that userspace can tell whether
         * the XSTATE header is present in addition to the "legacy" FPU
         * state.  We just assume that it is here.
         */
        fpregs += 0x70;
#endif
        pkru_offset = pkru_xstate_offset();
        pkru_ptr = (void *)(&fpregs[pkru_offset]);

        dprintf1("siginfo: %p\n", si);
        dprintf1(" fpregs: %p\n", fpregs);
        /*
         * If we got a PKRU fault, we *HAVE* to have at least one bit set in
         * here.
         */
        dprintf1("pkru_xstate_offset: %d\n", pkru_xstate_offset());
        if (DEBUG_LEVEL > 4)
                dump_mem(pkru_ptr - 128, 256);
        pkey_assert(*pkru_ptr);

        si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
        dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
        dump_mem(si_pkey_ptr - 8, 24);
        siginfo_pkey = *si_pkey_ptr;
        pkey_assert(siginfo_pkey < NR_PKEYS);
        last_si_pkey = siginfo_pkey;

        if ((si->si_code == SEGV_MAPERR) ||
            (si->si_code == SEGV_ACCERR) ||
            (si->si_code == SEGV_BNDERR)) {
                printf("non-PK si_code, exiting...\n");
                exit(4);
        }

        dprintf1("signal pkru from xsave: %08x\n", *pkru_ptr);
        /* need __rdpkru() version so we do not do shadow_pkru checking */
        dprintf1("signal pkru from  pkru: %08x\n", __rdpkru());
        dprintf1("pkey from siginfo: %jx\n", siginfo_pkey);
        *(u64 *)pkru_ptr = 0x00000000;
        dprintf1("WARNING: set PRKU=0 to allow faulting instruction to continue\n");
        pkru_faults++;
        dprintf1("<<<<==================================================\n");
        return;
        if (trapno == 14) {
                fprintf(stderr,
                        "ERROR: In signal handler, page fault, trapno = %d, ip = %016lx\n",
                        trapno, ip);
                fprintf(stderr, "si_addr %p\n", si->si_addr);
                fprintf(stderr, "REG_ERR: %lx\n",
                                (unsigned long)uctxt->uc_mcontext.gregs[REG_ERR]);
                exit(1);
        } else {
                fprintf(stderr, "unexpected trap %d! at 0x%lx\n", trapno, ip);
                fprintf(stderr, "si_addr %p\n", si->si_addr);
                fprintf(stderr, "REG_ERR: %lx\n",
                                (unsigned long)uctxt->uc_mcontext.gregs[REG_ERR]);
                exit(2);
        }
        dprint_in_signal = 0;
}

int wait_all_children(void)
{
        int status;
        return waitpid(-1, &status, 0);
}

void sig_chld(int x)
{
        dprint_in_signal = 1;
        dprintf2("[%d] SIGCHLD: %d\n", getpid(), x);
        dprint_in_signal = 0;
}

void setup_sigsegv_handler(void)
{
        int r, rs;
        struct sigaction newact;
        struct sigaction oldact;

        /* #PF is mapped to sigsegv */
        int signum  = SIGSEGV;

        newact.sa_handler = 0;
        newact.sa_sigaction = signal_handler;

        /*sigset_t - signals to block while in the handler */
        /* get the old signal mask. */
        rs = sigprocmask(SIG_SETMASK, 0, &newact.sa_mask);
        pkey_assert(rs == 0);

        /* call sa_sigaction, not sa_handler*/
        newact.sa_flags = SA_SIGINFO;

        newact.sa_restorer = 0;  /* void(*)(), obsolete */
        r = sigaction(signum, &newact, &oldact);
        r = sigaction(SIGALRM, &newact, &oldact);
        pkey_assert(r == 0);
}

void setup_handlers(void)
{
        signal(SIGCHLD, &sig_chld);
        setup_sigsegv_handler();
}

pid_t fork_lazy_child(void)
{
        pid_t forkret;

        forkret = fork();
        pkey_assert(forkret >= 0);
        dprintf3("[%d] fork() ret: %d\n", getpid(), forkret);

        if (!forkret) {
                /* in the child */
                while (1) {
                        dprintf1("child sleeping...\n");
                        sleep(30);
                }
        }
        return forkret;
}

#define PKEY_DISABLE_ACCESS    0x1
#define PKEY_DISABLE_WRITE     0x2

u32 pkey_get(int pkey, unsigned long flags)
{
        u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
        u32 pkru = __rdpkru();
        u32 shifted_pkru;
        u32 masked_pkru;

        dprintf1("%s(pkey=%d, flags=%lx) = %x / %d\n",
                        __func__, pkey, flags, 0, 0);
        dprintf2("%s() raw pkru: %x\n", __func__, pkru);

        shifted_pkru = (pkru >> (pkey * PKRU_BITS_PER_PKEY));
        dprintf2("%s() shifted_pkru: %x\n", __func__, shifted_pkru);
        masked_pkru = shifted_pkru & mask;
        dprintf2("%s() masked  pkru: %x\n", __func__, masked_pkru);
        /*
         * shift down the relevant bits to the lowest two, then
         * mask off all the other high bits.
         */
        return masked_pkru;
}

int pkey_set(int pkey, unsigned long rights, unsigned long flags)
{
        u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
        u32 old_pkru = __rdpkru();
        u32 new_pkru;

        /* make sure that 'rights' only contains the bits we expect: */
        assert(!(rights & ~mask));

        /* copy old pkru */
        new_pkru = old_pkru;
        /* mask out bits from pkey in old value: */
        new_pkru &= ~(mask << (pkey * PKRU_BITS_PER_PKEY));
        /* OR in new bits for pkey: */
        new_pkru |= (rights << (pkey * PKRU_BITS_PER_PKEY));

        __wrpkru(new_pkru);

        dprintf3("%s(pkey=%d, rights=%lx, flags=%lx) = %x pkru now: %x old_pkru: %x\n",
                        __func__, pkey, rights, flags, 0, __rdpkru(), old_pkru);
        return 0;
}

void pkey_disable_set(int pkey, int flags)
{
        unsigned long syscall_flags = 0;
        int ret;
        int pkey_rights;
        u32 orig_pkru = rdpkru();

        dprintf1("START->%s(%d, 0x%x)\n", __func__,
                pkey, flags);
        pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));

        pkey_rights = pkey_get(pkey, syscall_flags);

        dprintf1("%s(%d) pkey_get(%d): %x\n", __func__,
                        pkey, pkey, pkey_rights);
        pkey_assert(pkey_rights >= 0);

        pkey_rights |= flags;

        ret = pkey_set(pkey, pkey_rights, syscall_flags);
        assert(!ret);
        /*pkru and flags have the same format */
        shadow_pkru |= flags << (pkey * 2);
        dprintf1("%s(%d) shadow: 0x%x\n", __func__, pkey, shadow_pkru);

        pkey_assert(ret >= 0);

        pkey_rights = pkey_get(pkey, syscall_flags);
        dprintf1("%s(%d) pkey_get(%d): %x\n", __func__,
                        pkey, pkey, pkey_rights);

        dprintf1("%s(%d) pkru: 0x%x\n", __func__, pkey, rdpkru());
        if (flags)
                pkey_assert(rdpkru() > orig_pkru);
        dprintf1("END<---%s(%d, 0x%x)\n", __func__,
                pkey, flags);
}

void pkey_disable_clear(int pkey, int flags)
{
        unsigned long syscall_flags = 0;
        int ret;
        int pkey_rights = pkey_get(pkey, syscall_flags);
        u32 orig_pkru = rdpkru();

        pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));

        dprintf1("%s(%d) pkey_get(%d): %x\n", __func__,
                        pkey, pkey, pkey_rights);
        pkey_assert(pkey_rights >= 0);

        pkey_rights |= flags;

        ret = pkey_set(pkey, pkey_rights, 0);
        /* pkru and flags have the same format */
        shadow_pkru &= ~(flags << (pkey * 2));
        pkey_assert(ret >= 0);

        pkey_rights = pkey_get(pkey, syscall_flags);
        dprintf1("%s(%d) pkey_get(%d): %x\n", __func__,
                        pkey, pkey, pkey_rights);

        dprintf1("%s(%d) pkru: 0x%x\n", __func__, pkey, rdpkru());
        if (flags)
                assert(rdpkru() > orig_pkru);
}

void pkey_write_allow(int pkey)
{
        pkey_disable_clear(pkey, PKEY_DISABLE_WRITE);
}
void pkey_write_deny(int pkey)
{
        pkey_disable_set(pkey, PKEY_DISABLE_WRITE);
}
void pkey_access_allow(int pkey)
{
        pkey_disable_clear(pkey, PKEY_DISABLE_ACCESS);
}
void pkey_access_deny(int pkey)
{
        pkey_disable_set(pkey, PKEY_DISABLE_ACCESS);
}

int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
                unsigned long pkey)
{
        int sret;

        dprintf2("%s(0x%p, %zx, prot=%lx, pkey=%lx)\n", __func__,
                        ptr, size, orig_prot, pkey);

        errno = 0;
        sret = syscall(SYS_mprotect_key, ptr, size, orig_prot, pkey);
        if (errno) {
                dprintf2("SYS_mprotect_key sret: %d\n", sret);
                dprintf2("SYS_mprotect_key prot: 0x%lx\n", orig_prot);
                dprintf2("SYS_mprotect_key failed, errno: %d\n", errno);
                if (DEBUG_LEVEL >= 2)
                        perror("SYS_mprotect_pkey");
        }
        return sret;
}

int sys_pkey_alloc(unsigned long flags, unsigned long init_val)
{
        int ret = syscall(SYS_pkey_alloc, flags, init_val);
        dprintf1("%s(flags=%lx, init_val=%lx) syscall ret: %d errno: %d\n",
                        __func__, flags, init_val, ret, errno);
        return ret;
}

int alloc_pkey(void)
{
        int ret;
        unsigned long init_val = 0x0;

        dprintf1("alloc_pkey()::%d, pkru: 0x%x shadow: %x\n",
                        __LINE__, __rdpkru(), shadow_pkru);
        ret = sys_pkey_alloc(0, init_val);
        /*
         * pkey_alloc() sets PKRU, so we need to reflect it in
         * shadow_pkru:
         */
        dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        if (ret) {
                /* clear both the bits: */
                shadow_pkru &= ~(0x3      << (ret * 2));
                dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
                                __LINE__, ret, __rdpkru(), shadow_pkru);
                /*
                 * move the new state in from init_val
                 * (remember, we cheated and init_val == pkru format)
                 */
                shadow_pkru |=  (init_val << (ret * 2));
        }
        dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        dprintf1("alloc_pkey()::%d errno: %d\n", __LINE__, errno);
        /* for shadow checking: */
        rdpkru();
        dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        return ret;
}

int sys_pkey_free(unsigned long pkey)
{
        int ret = syscall(SYS_pkey_free, pkey);
        dprintf1("%s(pkey=%ld) syscall ret: %d\n", __func__, pkey, ret);
        return ret;
}

/*
 * I had a bug where pkey bits could be set by mprotect() but
 * not cleared.  This ensures we get lots of random bit sets
 * and clears on the vma and pte pkey bits.
 */
int alloc_random_pkey(void)
{
        int max_nr_pkey_allocs;
        int ret;
        int i;
        int alloced_pkeys[NR_PKEYS];
        int nr_alloced = 0;
        int random_index;
        memset(alloced_pkeys, 0, sizeof(alloced_pkeys));

        /* allocate every possible key and make a note of which ones we got */
        max_nr_pkey_allocs = NR_PKEYS;
        max_nr_pkey_allocs = 1;
        for (i = 0; i < max_nr_pkey_allocs; i++) {
                int new_pkey = alloc_pkey();
                if (new_pkey < 0)
                        break;
                alloced_pkeys[nr_alloced++] = new_pkey;
        }

        pkey_assert(nr_alloced > 0);
        /* select a random one out of the allocated ones */
        random_index = rand() % nr_alloced;
        ret = alloced_pkeys[random_index];
        /* now zero it out so we don't free it next */
        alloced_pkeys[random_index] = 0;

        /* go through the allocated ones that we did not want and free them */
        for (i = 0; i < nr_alloced; i++) {
                int free_ret;
                if (!alloced_pkeys[i])
                        continue;
                free_ret = sys_pkey_free(alloced_pkeys[i]);
                pkey_assert(!free_ret);
        }
        dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        return ret;
}

int mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
                unsigned long pkey)
{
        int nr_iterations = random() % 100;
        int ret;

        while (0) {
                int rpkey = alloc_random_pkey();
                ret = sys_mprotect_pkey(ptr, size, orig_prot, pkey);
                dprintf1("sys_mprotect_pkey(%p, %zx, prot=0x%lx, pkey=%ld) ret: %d\n",
                                ptr, size, orig_prot, pkey, ret);
                if (nr_iterations-- < 0)
                        break;

                dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
                        __LINE__, ret, __rdpkru(), shadow_pkru);
                sys_pkey_free(rpkey);
                dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        }
        pkey_assert(pkey < NR_PKEYS);

        ret = sys_mprotect_pkey(ptr, size, orig_prot, pkey);
        dprintf1("mprotect_pkey(%p, %zx, prot=0x%lx, pkey=%ld) ret: %d\n",
                        ptr, size, orig_prot, pkey, ret);
        pkey_assert(!ret);
        dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
                        __LINE__, ret, __rdpkru(), shadow_pkru);
        return ret;
}

struct pkey_malloc_record {
        void *ptr;
        long size;
};
struct pkey_malloc_record *pkey_malloc_records;
long nr_pkey_malloc_records;
void record_pkey_malloc(void *ptr, long size)
{
        long i;
        struct pkey_malloc_record *rec = NULL;

        for (i = 0; i < nr_pkey_malloc_records; i++) {
                rec = &pkey_malloc_records[i];
                /* find a free record */
                if (rec)
                        break;
        }
        if (!rec) {
                /* every record is full */
                size_t old_nr_records = nr_pkey_malloc_records;
                size_t new_nr_records = (nr_pkey_malloc_records * 2 + 1);
                size_t new_size = new_nr_records * sizeof(struct pkey_malloc_record);
                dprintf2("new_nr_records: %zd\n", new_nr_records);
                dprintf2("new_size: %zd\n", new_size);
                pkey_malloc_records = realloc(pkey_malloc_records, new_size);
                pkey_assert(pkey_malloc_records != NULL);
                rec = &pkey_malloc_records[nr_pkey_malloc_records];
                /*
                 * realloc() does not initialize memory, so zero it from
                 * the first new record all the way to the end.
                 */
                for (i = 0; i < new_nr_records - old_nr_records; i++)
                        memset(rec + i, 0, sizeof(*rec));
        }
        dprintf3("filling malloc record[%d/%p]: {%p, %ld}\n",
                (int)(rec - pkey_malloc_records), rec, ptr, size);
        rec->ptr = ptr;
        rec->size = size;
        nr_pkey_malloc_records++;
}

void free_pkey_malloc(void *ptr)
{
        long i;
        int ret;
        dprintf3("%s(%p)\n", __func__, ptr);
        for (i = 0; i < nr_pkey_malloc_records; i++) {
                struct pkey_malloc_record *rec = &pkey_malloc_records[i];
                dprintf4("looking for ptr %p at record[%ld/%p]: {%p, %ld}\n",
                                ptr, i, rec, rec->ptr, rec->size);
                if ((ptr <  rec->ptr) ||
                    (ptr >= rec->ptr + rec->size))
                        continue;

                dprintf3("found ptr %p at record[%ld/%p]: {%p, %ld}\n",
                                ptr, i, rec, rec->ptr, rec->size);
                nr_pkey_malloc_records--;
                ret = munmap(rec->ptr, rec->size);
                dprintf3("munmap ret: %d\n", ret);
                pkey_assert(!ret);
                dprintf3("clearing rec->ptr, rec: %p\n", rec);
                rec->ptr = NULL;
                dprintf3("done clearing rec->ptr, rec: %p\n", rec);
                return;
        }
        pkey_assert(false);
}


void *malloc_pkey_with_mprotect(long size, int prot, u16 pkey)
{
        void *ptr;
        int ret;

        rdpkru();
        dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
                        size, prot, pkey);
        pkey_assert(pkey < NR_PKEYS);
        ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
        pkey_assert(ptr != (void *)-1);
        ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
        pkey_assert(!ret);
        record_pkey_malloc(ptr, size);
        rdpkru();

        dprintf1("%s() for pkey %d @ %p\n", __func__, pkey, ptr);
        return ptr;
}

void *malloc_pkey_anon_huge(long size, int prot, u16 pkey)
{
        int ret;
        void *ptr;

        dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
                        size, prot, pkey);
        /*
         * Guarantee we can fit at least one huge page in the resulting
         * allocation by allocating space for 2:
         */
        size = ALIGN_UP(size, HPAGE_SIZE * 2);
        ptr = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
        pkey_assert(ptr != (void *)-1);
        record_pkey_malloc(ptr, size);
        mprotect_pkey(ptr, size, prot, pkey);

        dprintf1("unaligned ptr: %p\n", ptr);
        ptr = ALIGN_PTR_UP(ptr, HPAGE_SIZE);
        dprintf1("  aligned ptr: %p\n", ptr);
        ret = madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE);
        dprintf1("MADV_HUGEPAGE ret: %d\n", ret);
        ret = madvise(ptr, HPAGE_SIZE, MADV_WILLNEED);
        dprintf1("MADV_WILLNEED ret: %d\n", ret);
        memset(ptr, 0, HPAGE_SIZE);

        dprintf1("mmap()'d thp for pkey %d @ %p\n", pkey, ptr);
        return ptr;
}

int hugetlb_setup_ok;
#define GET_NR_HUGE_PAGES 10
void setup_hugetlbfs(void)
{
        int err;
        int fd;
        char buf[] = "123";

        if (geteuid() != 0) {
                fprintf(stderr, "WARNING: not run as root, can not do hugetlb test\n");
                return;
        }

        cat_into_file(__stringify(GET_NR_HUGE_PAGES), "/proc/sys/vm/nr_hugepages");

        /*
         * Now go make sure that we got the pages and that they
         * are 2M pages.  Someone might have made 1G the default.
         */
        fd = open("/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages", O_RDONLY);
        if (fd < 0) {
                perror("opening sysfs 2M hugetlb config");
                return;
        }

        /* -1 to guarantee leaving the trailing \0 */
        err = read(fd, buf, sizeof(buf)-1);
        close(fd);
        if (err <= 0) {
                perror("reading sysfs 2M hugetlb config");
                return;
        }

        if (atoi(buf) != GET_NR_HUGE_PAGES) {
                fprintf(stderr, "could not confirm 2M pages, got: '%s' expected %d\n",
                        buf, GET_NR_HUGE_PAGES);
                return;
        }

        hugetlb_setup_ok = 1;
}

void *malloc_pkey_hugetlb(long size, int prot, u16 pkey)
{
        void *ptr;
        int flags = MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB;

        if (!hugetlb_setup_ok)
                return PTR_ERR_ENOTSUP;

        dprintf1("doing %s(%ld, %x, %x)\n", __func__, size, prot, pkey);
        size = ALIGN_UP(size, HPAGE_SIZE * 2);
        pkey_assert(pkey < NR_PKEYS);
        ptr = mmap(NULL, size, PROT_NONE, flags, -1, 0);
        pkey_assert(ptr != (void *)-1);
        mprotect_pkey(ptr, size, prot, pkey);

        record_pkey_malloc(ptr, size);

        dprintf1("mmap()'d hugetlbfs for pkey %d @ %p\n", pkey, ptr);
        return ptr;
}

void *malloc_pkey_mmap_dax(long size, int prot, u16 pkey)
{
        void *ptr;
        int fd;

        dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
                        size, prot, pkey);
        pkey_assert(pkey < NR_PKEYS);
        fd = open("/dax/foo", O_RDWR);
        pkey_assert(fd >= 0);

        ptr = mmap(0, size, prot, MAP_SHARED, fd, 0);
        pkey_assert(ptr != (void *)-1);

        mprotect_pkey(ptr, size, prot, pkey);

        record_pkey_malloc(ptr, size);

        dprintf1("mmap()'d for pkey %d @ %p\n", pkey, ptr);
        close(fd);
        return ptr;
}

void *(*pkey_malloc[])(long size, int prot, u16 pkey) = {

        malloc_pkey_with_mprotect,
        malloc_pkey_anon_huge,
        malloc_pkey_hugetlb
/* can not do direct with the pkey_mprotect() API:
        malloc_pkey_mmap_direct,
        malloc_pkey_mmap_dax,
*/
};

void *malloc_pkey(long size, int prot, u16 pkey)
{
        void *ret;
        static int malloc_type;
        int nr_malloc_types = ARRAY_SIZE(pkey_malloc);

        pkey_assert(pkey < NR_PKEYS);

        while (1) {
                pkey_assert(malloc_type < nr_malloc_types);

                ret = pkey_malloc[malloc_type](size, prot, pkey);
                pkey_assert(ret != (void *)-1);

                malloc_type++;
                if (malloc_type >= nr_malloc_types)
                        malloc_type = (random()%nr_malloc_types);

                /* try again if the malloc_type we tried is unsupported */
                if (ret == PTR_ERR_ENOTSUP)
                        continue;

                break;
        }

        dprintf3("%s(%ld, prot=%x, pkey=%x) returning: %p\n", __func__,
                        size, prot, pkey, ret);
        return ret;
}

int last_pkru_faults;
void expected_pk_fault(int pkey)
{
        dprintf2("%s(): last_pkru_faults: %d pkru_faults: %d\n",
                        __func__, last_pkru_faults, pkru_faults);
        dprintf2("%s(%d): last_si_pkey: %d\n", __func__, pkey, last_si_pkey);
        pkey_assert(last_pkru_faults + 1 == pkru_faults);
        pkey_assert(last_si_pkey == pkey);
        /*
         * The signal handler shold have cleared out PKRU to let the
         * test program continue.  We now have to restore it.
         */
        if (__rdpkru() != 0)
                pkey_assert(0);

        __wrpkru(shadow_pkru);
        dprintf1("%s() set PKRU=%x to restore state after signal nuked it\n",
                        __func__, shadow_pkru);
        last_pkru_faults = pkru_faults;
        last_si_pkey = -1;
}

void do_not_expect_pk_fault(void)
{
        pkey_assert(last_pkru_faults == pkru_faults);
}

int test_fds[10] = { -1 };
int nr_test_fds;
void __save_test_fd(int fd)
{
        pkey_assert(fd >= 0);
        pkey_assert(nr_test_fds < ARRAY_SIZE(test_fds));
        test_fds[nr_test_fds] = fd;
        nr_test_fds++;
}

int get_test_read_fd(void)
{
        int test_fd = open("/etc/passwd", O_RDONLY);
        __save_test_fd(test_fd);
        return test_fd;
}

void close_test_fds(void)
{
        int i;

        for (i = 0; i < nr_test_fds; i++) {
                if (test_fds[i] < 0)
                        continue;
                close(test_fds[i]);
                test_fds[i] = -1;
        }
        nr_test_fds = 0;
}

#define barrier() __asm__ __volatile__("": : :"memory")
__attribute__((noinline)) int read_ptr(int *ptr)
{
        /*
         * Keep GCC from optimizing this away somehow
         */
        barrier();
        return *ptr;
}

void test_read_of_write_disabled_region(int *ptr, u16 pkey)
{
        int ptr_contents;

        dprintf1("disabling write access to PKEY[1], doing read\n");
        pkey_write_deny(pkey);
        ptr_contents = read_ptr(ptr);
        dprintf1("*ptr: %d\n", ptr_contents);
        dprintf1("\n");
}
void test_read_of_access_disabled_region(int *ptr, u16 pkey)
{
        int ptr_contents;

        dprintf1("disabling access to PKEY[%02d], doing read @ %p\n", pkey, ptr);
        rdpkru();
        pkey_access_deny(pkey);
        ptr_contents = read_ptr(ptr);
        dprintf1("*ptr: %d\n", ptr_contents);
        expected_pk_fault(pkey);
}
void test_write_of_write_disabled_region(int *ptr, u16 pkey)
{
        dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
        pkey_write_deny(pkey);
        *ptr = __LINE__;
        expected_pk_fault(pkey);
}
void test_write_of_access_disabled_region(int *ptr, u16 pkey)
{
        dprintf1("disabling access to PKEY[%02d], doing write\n", pkey);
        pkey_access_deny(pkey);
        *ptr = __LINE__;
        expected_pk_fault(pkey);
}
void test_kernel_write_of_access_disabled_region(int *ptr, u16 pkey)
{
        int ret;
        int test_fd = get_test_read_fd();

        dprintf1("disabling access to PKEY[%02d], "
                 "having kernel read() to buffer\n", pkey);
        pkey_access_deny(pkey);
        ret = read(test_fd, ptr, 1);
        dprintf1("read ret: %d\n", ret);
        pkey_assert(ret);
}
void test_kernel_write_of_write_disabled_region(int *ptr, u16 pkey)
{
        int ret;
        int test_fd = get_test_read_fd();

        pkey_write_deny(pkey);
        ret = read(test_fd, ptr, 100);
        dprintf1("read ret: %d\n", ret);
        if (ret < 0 && (DEBUG_LEVEL > 0))
                perror("verbose read result (OK for this to be bad)");
        pkey_assert(ret);
}

void test_kernel_gup_of_access_disabled_region(int *ptr, u16 pkey)
{
        int pipe_ret, vmsplice_ret;
        struct iovec iov;
        int pipe_fds[2];

        pipe_ret = pipe(pipe_fds);

        pkey_assert(pipe_ret == 0);
        dprintf1("disabling access to PKEY[%02d], "
                 "having kernel vmsplice from buffer\n", pkey);
        pkey_access_deny(pkey);
        iov.iov_base = ptr;
        iov.iov_len = PAGE_SIZE;
        vmsplice_ret = vmsplice(pipe_fds[1], &iov, 1, SPLICE_F_GIFT);
        dprintf1("vmsplice() ret: %d\n", vmsplice_ret);
        pkey_assert(vmsplice_ret == -1);

        close(pipe_fds[0]);
        close(pipe_fds[1]);
}

void test_kernel_gup_write_to_write_disabled_region(int *ptr, u16 pkey)
{
        int ignored = 0xdada;
        int futex_ret;
        int some_int = __LINE__;

        dprintf1("disabling write to PKEY[%02d], "
                 "doing futex gunk in buffer\n", pkey);
        *ptr = some_int;
        pkey_write_deny(pkey);
        futex_ret = syscall(SYS_futex, ptr, FUTEX_WAIT, some_int-1, NULL,
                        &ignored, ignored);
        if (DEBUG_LEVEL > 0)
                perror("futex");
        dprintf1("futex() ret: %d\n", futex_ret);
}

/* Assumes that all pkeys other than 'pkey' are unallocated */
void test_pkey_syscalls_on_non_allocated_pkey(int *ptr, u16 pkey)
{
        int err;
        int i;

        /* Note: 0 is the default pkey, so don't mess with it */
        for (i = 1; i < NR_PKEYS; i++) {
                if (pkey == i)
                        continue;

                dprintf1("trying get/set/free to non-allocated pkey: %2d\n", i);
                err = sys_pkey_free(i);
                pkey_assert(err);

                err = sys_pkey_free(i);
                pkey_assert(err);

                err = sys_mprotect_pkey(ptr, PAGE_SIZE, PROT_READ, i);
                pkey_assert(err);
        }
}

/* Assumes that all pkeys other than 'pkey' are unallocated */
void test_pkey_syscalls_bad_args(int *ptr, u16 pkey)
{
        int err;
        int bad_pkey = NR_PKEYS+99;

        /* pass a known-invalid pkey in: */
        err = sys_mprotect_pkey(ptr, PAGE_SIZE, PROT_READ, bad_pkey);
        pkey_assert(err);
}

/* Assumes that all pkeys other than 'pkey' are unallocated */
void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
{
        int err;
        int allocated_pkeys[NR_PKEYS] = {0};
        int nr_allocated_pkeys = 0;
        int i;

        for (i = 0; i < NR_PKEYS*2; i++) {
                int new_pkey;
                dprintf1("%s() alloc loop: %d\n", __func__, i);
                new_pkey = alloc_pkey();
                dprintf4("%s()::%d, err: %d pkru: 0x%x shadow: 0x%x\n", __func__,
                                __LINE__, err, __rdpkru(), shadow_pkru);
                rdpkru(); /* for shadow checking */
                dprintf2("%s() errno: %d ENOSPC: %d\n", __func__, errno, ENOSPC);
                if ((new_pkey == -1) && (errno == ENOSPC)) {
                        dprintf2("%s() failed to allocate pkey after %d tries\n",
                                __func__, nr_allocated_pkeys);
                        break;
                }
                pkey_assert(nr_allocated_pkeys < NR_PKEYS);
                allocated_pkeys[nr_allocated_pkeys++] = new_pkey;
        }

        dprintf3("%s()::%d\n", __func__, __LINE__);

        /*
         * ensure it did not reach the end of the loop without
         * failure:
         */
        pkey_assert(i < NR_PKEYS*2);

        /*
         * There are 16 pkeys supported in hardware.  One is taken
         * up for the default (0) and another can be taken up by
         * an execute-only mapping.  Ensure that we can allocate
         * at least 14 (16-2).
         */
        pkey_assert(i >= NR_PKEYS-2);

        for (i = 0; i < nr_allocated_pkeys; i++) {
                err = sys_pkey_free(allocated_pkeys[i]);
                pkey_assert(!err);
                rdpkru(); /* for shadow checking */
        }
}

void test_ptrace_of_child(int *ptr, u16 pkey)
{
        __attribute__((__unused__)) int peek_result;
        pid_t child_pid;
        void *ignored = 0;
        long ret;
        int status;
        /*
         * This is the "control" for our little expermient.  Make sure
         * we can always access it when ptracing.
         */
        int *plain_ptr_unaligned = malloc(HPAGE_SIZE);
        int *plain_ptr = ALIGN_PTR_UP(plain_ptr_unaligned, PAGE_SIZE);

        /*
         * Fork a child which is an exact copy of this process, of course.
         * That means we can do all of our tests via ptrace() and then plain
         * memory access and ensure they work differently.
         */
        child_pid = fork_lazy_child();
        dprintf1("[%d] child pid: %d\n", getpid(), child_pid);

        ret = ptrace(PTRACE_ATTACH, child_pid, ignored, ignored);
        if (ret)
                perror("attach");
        dprintf1("[%d] attach ret: %ld %d\n", getpid(), ret, __LINE__);
        pkey_assert(ret != -1);
        ret = waitpid(child_pid, &status, WUNTRACED);
        if ((ret != child_pid) || !(WIFSTOPPED(status))) {
                fprintf(stderr, "weird waitpid result %ld stat %x\n",
                                ret, status);
                pkey_assert(0);
        }
        dprintf2("waitpid ret: %ld\n", ret);
        dprintf2("waitpid status: %d\n", status);

        pkey_access_deny(pkey);
        pkey_write_deny(pkey);

        /* Write access, untested for now:
        ret = ptrace(PTRACE_POKEDATA, child_pid, peek_at, data);
        pkey_assert(ret != -1);
        dprintf1("poke at %p: %ld\n", peek_at, ret);
        */

        /*
         * Try to access the pkey-protected "ptr" via ptrace:
         */
        ret = ptrace(PTRACE_PEEKDATA, child_pid, ptr, ignored);
        /* expect it to work, without an error: */
        pkey_assert(ret != -1);
        /* Now access from the current task, and expect an exception: */
        peek_result = read_ptr(ptr);
        expected_pk_fault(pkey);

        /*
         * Try to access the NON-pkey-protected "plain_ptr" via ptrace:
         */
        ret = ptrace(PTRACE_PEEKDATA, child_pid, plain_ptr, ignored);
        /* expect it to work, without an error: */
        pkey_assert(ret != -1);
        /* Now access from the current task, and expect NO exception: */
        peek_result = read_ptr(plain_ptr);
        do_not_expect_pk_fault();

        ret = ptrace(PTRACE_DETACH, child_pid, ignored, 0);
        pkey_assert(ret != -1);

        ret = kill(child_pid, SIGKILL);
        pkey_assert(ret != -1);

        wait(&status);

        free(plain_ptr_unaligned);
}

void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
{
        void *p1;
        int scratch;
        int ptr_contents;
        int ret;

        p1 = ALIGN_PTR_UP(&lots_o_noops_around_write, PAGE_SIZE);
        dprintf3("&lots_o_noops: %p\n", &lots_o_noops_around_write);
        /* lots_o_noops_around_write should be page-aligned already */
        assert(p1 == &lots_o_noops_around_write);

        /* Point 'p1' at the *second* page of the function: */
        p1 += PAGE_SIZE;

        madvise(p1, PAGE_SIZE, MADV_DONTNEED);
        lots_o_noops_around_write(&scratch);
        ptr_contents = read_ptr(p1);
        dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);

        ret = mprotect_pkey(p1, PAGE_SIZE, PROT_EXEC, (u64)pkey);
        pkey_assert(!ret);
        pkey_access_deny(pkey);

        dprintf2("pkru: %x\n", rdpkru());

        /*
         * Make sure this is an *instruction* fault
         */
        madvise(p1, PAGE_SIZE, MADV_DONTNEED);
        lots_o_noops_around_write(&scratch);
        do_not_expect_pk_fault();
        ptr_contents = read_ptr(p1);
        dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
        expected_pk_fault(pkey);
}

void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
{
        int size = PAGE_SIZE;
        int sret;

        if (cpu_has_pku()) {
                dprintf1("SKIP: %s: no CPU support\n", __func__);
                return;
        }

        sret = syscall(SYS_mprotect_key, ptr, size, PROT_READ, pkey);
        pkey_assert(sret < 0);
}

void (*pkey_tests[])(int *ptr, u16 pkey) = {
        test_read_of_write_disabled_region,
        test_read_of_access_disabled_region,
        test_write_of_write_disabled_region,
        test_write_of_access_disabled_region,
        test_kernel_write_of_access_disabled_region,
        test_kernel_write_of_write_disabled_region,
        test_kernel_gup_of_access_disabled_region,
        test_kernel_gup_write_to_write_disabled_region,
        test_executing_on_unreadable_memory,
        test_ptrace_of_child,
        test_pkey_syscalls_on_non_allocated_pkey,
        test_pkey_syscalls_bad_args,
        test_pkey_alloc_exhaust,
};

void run_tests_once(void)
{
        int *ptr;
        int prot = PROT_READ|PROT_WRITE;

        for (test_nr = 0; test_nr < ARRAY_SIZE(pkey_tests); test_nr++) {
                int pkey;
                int orig_pkru_faults = pkru_faults;

                dprintf1("======================\n");
                dprintf1("test %d preparing...\n", test_nr);

                tracing_on();
                pkey = alloc_random_pkey();
                dprintf1("test %d starting with pkey: %d\n", test_nr, pkey);
                ptr = malloc_pkey(PAGE_SIZE, prot, pkey);
                dprintf1("test %d starting...\n", test_nr);
                pkey_tests[test_nr](ptr, pkey);
                dprintf1("freeing test memory: %p\n", ptr);
                free_pkey_malloc(ptr);
                sys_pkey_free(pkey);

                dprintf1("pkru_faults: %d\n", pkru_faults);
                dprintf1("orig_pkru_faults: %d\n", orig_pkru_faults);

                tracing_off();
                close_test_fds();

                printf("test %2d PASSED (iteration %d)\n", test_nr, iteration_nr);
                dprintf1("======================\n\n");
        }
        iteration_nr++;
}

void pkey_setup_shadow(void)
{
        shadow_pkru = __rdpkru();
}

int main(void)
{
        int nr_iterations = 22;

        setup_handlers();

        printf("has pku: %d\n", cpu_has_pku());

        if (!cpu_has_pku()) {
                int size = PAGE_SIZE;
                int *ptr;

                printf("running PKEY tests for unsupported CPU/OS\n");

                ptr  = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
                assert(ptr != (void *)-1);
                test_mprotect_pkey_on_unsupported_cpu(ptr, 1);
                exit(0);
        }

        pkey_setup_shadow();
        printf("startup pkru: %x\n", rdpkru());
        setup_hugetlbfs();

        while (nr_iterations-- > 0)
                run_tests_once();

        printf("done (all tests OK)\n");
        return 0;
}