/*

 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright 2004-2014, Akamai Technologies. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * This file is in two halves. The first half implements the public API

 * to be used by external consumers, and to be used by OpenSSL to store

 * data in a "secure arena." The second half implements the secure arena.

 * For details on that implementation, see below (look for uppercase

 * "SECURE HEAP IMPLEMENTATION").

 */

#include "e_os.h"

#include <openssl/crypto.h>

#include <string.h>

/* e_os.h includes unistd.h, which defines _POSIX_VERSION */

#if !defined(OPENSSL_NO_SECURE_MEMORY) && defined(OPENSSL_SYS_UNIX) \

    && ( (defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L) \

         || defined(__sun) || defined(__hpux) || defined(__sgi) \

         || defined(__osf__) )

# define IMPLEMENTED

# include <stdlib.h>

# include <assert.h>

# include <unistd.h>

# include <sys/types.h>

# include <sys/mman.h>

# if defined(OPENSSL_SYS_LINUX)

#  include <sys/syscall.h>

#  if defined(SYS_mlock2)

#   include <linux/mman.h>

#   include <errno.h>

#  endif

# endif

# include <sys/param.h>

# include <sys/stat.h>

# include <fcntl.h>

#endif

#define CLEAR(p, s) OPENSSL_cleanse(p, s)

#ifndef PAGE_SIZE

# define PAGE_SIZE    4096

#endif

#if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)

# define MAP_ANON MAP_ANONYMOUS

#endif

#ifdef IMPLEMENTED

static size_t secure_mem_used;

static int secure_mem_initialized;

static CRYPTO_RWLOCK *sec_malloc_lock = NULL;

/*

 * These are the functions that must be implemented by a secure heap (sh).

 */

static int sh_init(size_t size, int minsize);

static void *sh_malloc(size_t size);

static void sh_free(void *ptr);

static void sh_done(void);

static size_t sh_actual_size(char *ptr);

static int sh_allocated(const char *ptr);

#endif

int CRYPTO_secure_malloc_init(size_t size, int minsize)

{

#ifdef IMPLEMENTED

    int ret = 0;

    if (!secure_mem_initialized) {

        sec_malloc_lock = CRYPTO_THREAD_lock_new();

        if (sec_malloc_lock == NULL)

            return 0;

        if ((ret = sh_init(size, minsize)) != 0) {

            secure_mem_initialized = 1;

        } else {

            CRYPTO_THREAD_lock_free(sec_malloc_lock);

            sec_malloc_lock = NULL;

        }

    }

    return ret;

#else

    return 0;

#endif /* IMPLEMENTED */

}

int CRYPTO_secure_malloc_done(void)

{

#ifdef IMPLEMENTED

    if (secure_mem_used == 0) {

        sh_done();

        secure_mem_initialized = 0;

        CRYPTO_THREAD_lock_free(sec_malloc_lock);

        sec_malloc_lock = NULL;

        return 1;

    }

#endif /* IMPLEMENTED */

    return 0;

}

int CRYPTO_secure_malloc_initialized(void)

{

#ifdef IMPLEMENTED

    return secure_mem_initialized;

#else

    return 0;

#endif /* IMPLEMENTED */

}

void *CRYPTO_secure_malloc(size_t num, const char *file, int line)

{

#ifdef IMPLEMENTED

    void *ret;

    size_t actual_size;

    if (!secure_mem_initialized) {

        return CRYPTO_malloc(num, file, line);

    }

    CRYPTO_THREAD_write_lock(sec_malloc_lock);

    ret = sh_malloc(num);

    actual_size = ret ? sh_actual_size(ret) : 0;

    secure_mem_used += actual_size;

    CRYPTO_THREAD_unlock(sec_malloc_lock);

    return ret;

#else

    return CRYPTO_malloc(num, file, line);

#endif /* IMPLEMENTED */

}

void *CRYPTO_secure_zalloc(size_t num, const char *file, int line)

{

#ifdef IMPLEMENTED

    if (secure_mem_initialized)

        /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */

        return CRYPTO_secure_malloc(num, file, line);

#endif

    return CRYPTO_zalloc(num, file, line);

}

void CRYPTO_secure_free(void *ptr, const char *file, int line)

{

#ifdef IMPLEMENTED

    size_t actual_size;

    if (ptr == NULL)

        return;

    if (!CRYPTO_secure_allocated(ptr)) {

        CRYPTO_free(ptr, file, line);

        return;

    }

    CRYPTO_THREAD_write_lock(sec_malloc_lock);

    actual_size = sh_actual_size(ptr);

    CLEAR(ptr, actual_size);

    secure_mem_used -= actual_size;

    sh_free(ptr);

    CRYPTO_THREAD_unlock(sec_malloc_lock);

#else

    CRYPTO_free(ptr, file, line);

#endif /* IMPLEMENTED */

}

void CRYPTO_secure_clear_free(void *ptr, size_t num,

                              const char *file, int line)

{

#ifdef IMPLEMENTED

    size_t actual_size;

    if (ptr == NULL)

        return;

    if (!CRYPTO_secure_allocated(ptr)) {

        OPENSSL_cleanse(ptr, num);

        CRYPTO_free(ptr, file, line);

        return;

    }

    CRYPTO_THREAD_write_lock(sec_malloc_lock);

    actual_size = sh_actual_size(ptr);

    CLEAR(ptr, actual_size);

    secure_mem_used -= actual_size;

    sh_free(ptr);

    CRYPTO_THREAD_unlock(sec_malloc_lock);

#else

    if (ptr == NULL)

        return;

    OPENSSL_cleanse(ptr, num);

    CRYPTO_free(ptr, file, line);

#endif /* IMPLEMENTED */

}

int CRYPTO_secure_allocated(const void *ptr)

{

#ifdef IMPLEMENTED

    int ret;

    if (!secure_mem_initialized)

        return 0;

    CRYPTO_THREAD_write_lock(sec_malloc_lock);

    ret = sh_allocated(ptr);

    CRYPTO_THREAD_unlock(sec_malloc_lock);

    return ret;

#else

    return 0;

#endif /* IMPLEMENTED */

}

size_t CRYPTO_secure_used(void)

{

#ifdef IMPLEMENTED

    return secure_mem_used;

#else

    return 0;

#endif /* IMPLEMENTED */

}

size_t CRYPTO_secure_actual_size(void *ptr)

{

#ifdef IMPLEMENTED

    size_t actual_size;

    CRYPTO_THREAD_write_lock(sec_malloc_lock);

    actual_size = sh_actual_size(ptr);

    CRYPTO_THREAD_unlock(sec_malloc_lock);

    return actual_size;

#else

    return 0;

#endif

}

/* END OF PAGE ...

   ... START OF PAGE */

/*

 * SECURE HEAP IMPLEMENTATION

 */

#ifdef IMPLEMENTED

/*

 * The implementation provided here uses a fixed-sized mmap() heap,

 * which is locked into memory, not written to core files, and protected

 * on either side by an unmapped page, which will catch pointer overruns

 * (or underruns) and an attempt to read data out of the secure heap.

 * Free'd memory is zero'd or otherwise cleansed.

 *

 * This is a pretty standard buddy allocator.  We keep areas in a multiple

 * of "sh.minsize" units.  The freelist and bitmaps are kept separately,

 * so all (and only) data is kept in the mmap'd heap.

 *

 * This code assumes eight-bit bytes.  The numbers 3 and 7 are all over the

 * place.

 */

#define ONE ((size_t)1)

# define TESTBIT(t, b)  (t[(b) >> 3] &  (ONE << ((b) & 7)))

# define SETBIT(t, b)   (t[(b) >> 3] |= (ONE << ((b) & 7)))

# define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))

#define WITHIN_ARENA(p) \

    ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])

#define WITHIN_FREELIST(p) \

    ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])

typedef struct sh_list_st

{

    struct sh_list_st *next;

    struct sh_list_st **p_next;

} SH_LIST;

typedef struct sh_st

{

    char* map_result;

    size_t map_size;

    char *arena;

    size_t arena_size;

    char **freelist;

    ossl_ssize_t freelist_size;

    size_t minsize;

    unsigned char *bittable;

    unsigned char *bitmalloc;

    size_t bittable_size; /* size in bits */

} SH;

static SH sh;

static size_t sh_getlist(char *ptr)

{

    ossl_ssize_t list = sh.freelist_size - 1;

    size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize;

    for (; bit; bit >>= 1, list--) {

        if (TESTBIT(sh.bittable, bit))

            break;

        OPENSSL_assert((bit & 1) == 0);

    }

    return list;

}

static int sh_testbit(char *ptr, int list, unsigned char *table)

{

    size_t bit;

    OPENSSL_assert(list >= 0 && list < sh.freelist_size);

    OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);

    bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));

    OPENSSL_assert(bit > 0 && bit < sh.bittable_size);

    return TESTBIT(table, bit);

}

static void sh_clearbit(char *ptr, int list, unsigned char *table)

{

    size_t bit;

    OPENSSL_assert(list >= 0 && list < sh.freelist_size);

    OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);

    bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));

    OPENSSL_assert(bit > 0 && bit < sh.bittable_size);

    OPENSSL_assert(TESTBIT(table, bit));

    CLEARBIT(table, bit);

}

static void sh_setbit(char *ptr, int list, unsigned char *table)

{

    size_t bit;

    OPENSSL_assert(list >= 0 && list < sh.freelist_size);

    OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);

    bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));

    OPENSSL_assert(bit > 0 && bit < sh.bittable_size);

    OPENSSL_assert(!TESTBIT(table, bit));

    SETBIT(table, bit);

}

static void sh_add_to_list(char **list, char *ptr)

{

    SH_LIST *temp;

    OPENSSL_assert(WITHIN_FREELIST(list));

    OPENSSL_assert(WITHIN_ARENA(ptr));

    temp = (SH_LIST *)ptr;

    temp->next = *(SH_LIST **)list;

    OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next));

    temp->p_next = (SH_LIST **)list;

    if (temp->next != NULL) {

        OPENSSL_assert((char **)temp->next->p_next == list);

        temp->next->p_next = &(temp->next);

    }

    *list = ptr;

}

static void sh_remove_from_list(char *ptr)

{

    SH_LIST *temp, *temp2;

    temp = (SH_LIST *)ptr;

    if (temp->next != NULL)

        temp->next->p_next = temp->p_next;

    *temp->p_next = temp->next;

    if (temp->next == NULL)

        return;

    temp2 = temp->next;

    OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next));

}

static int sh_init(size_t size, int minsize)

{

    int ret;

    size_t i;

    size_t pgsize;

    size_t aligned;

    memset(&sh, 0, sizeof(sh));

    /* make sure size and minsize are powers of 2 */

    OPENSSL_assert(size > 0);

    OPENSSL_assert((size & (size - 1)) == 0);

    OPENSSL_assert(minsize > 0);

    OPENSSL_assert((minsize & (minsize - 1)) == 0);

    if (size <= 0 || (size & (size - 1)) != 0)

        goto err;

    if (minsize <= 0 || (minsize & (minsize - 1)) != 0)

        goto err;

    while (minsize < (int)sizeof(SH_LIST))

        minsize *= 2;

    sh.arena_size = size;

    sh.minsize = minsize;

    sh.bittable_size = (sh.arena_size / sh.minsize) * 2;

    /* Prevent allocations of size 0 later on */

    if (sh.bittable_size >> 3 == 0)

        goto err;

    sh.freelist_size = -1;

    for (i = sh.bittable_size; i; i >>= 1)

        sh.freelist_size++;

    sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *));

    OPENSSL_assert(sh.freelist != NULL);

    if (sh.freelist == NULL)

        goto err;

    sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3);

    OPENSSL_assert(sh.bittable != NULL);

    if (sh.bittable == NULL)

        goto err;

    sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3);

    OPENSSL_assert(sh.bitmalloc != NULL);

    if (sh.bitmalloc == NULL)

        goto err;

    /* Allocate space for heap, and two extra pages as guards */

#if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)

    {

# if defined(_SC_PAGE_SIZE)

        long tmppgsize = sysconf(_SC_PAGE_SIZE);

# else

        long tmppgsize = sysconf(_SC_PAGESIZE);

# endif

        if (tmppgsize < 1)

            pgsize = PAGE_SIZE;

        else

            pgsize = (size_t)tmppgsize;

    }

#else

    pgsize = PAGE_SIZE;

#endif

    sh.map_size = pgsize + sh.arena_size + pgsize;

    if (1) {

#ifdef MAP_ANON

        sh.map_result = mmap(NULL, sh.map_size,

                             PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);

    } else {

#endif

        int fd;

        sh.map_result = MAP_FAILED;

        if ((fd = open("/dev/zero", O_RDWR)) >= 0) {

            sh.map_result = mmap(NULL, sh.map_size,

                                 PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);

            close(fd);

        }

    }

    if (sh.map_result == MAP_FAILED)

        goto err;

    sh.arena = (char *)(sh.map_result + pgsize);

    sh_setbit(sh.arena, 0, sh.bittable);

    sh_add_to_list(&sh.freelist[0], sh.arena);

    /* Now try to add guard pages and lock into memory. */

    ret = 1;

    /* Starting guard is already aligned from mmap. */

    if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0)

        ret = 2;

    /* Ending guard page - need to round up to page boundary */

    aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1);

    if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0)

        ret = 2;

#if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)

    if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) {

        if (errno == ENOSYS) {

            if (mlock(sh.arena, sh.arena_size) < 0)

                ret = 2;

        } else {

            ret = 2;

        }

    }

#else

    if (mlock(sh.arena, sh.arena_size) < 0)

        ret = 2;

#endif

#ifdef MADV_DONTDUMP

    if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0)

        ret = 2;

#endif

    return ret;

 err:

    sh_done();

    return 0;

}

static void sh_done(void)

{

    OPENSSL_free(sh.freelist);

    OPENSSL_free(sh.bittable);

    OPENSSL_free(sh.bitmalloc);

    if (sh.map_result != NULL && sh.map_size)

        munmap(sh.map_result, sh.map_size);

    memset(&sh, 0, sizeof(sh));

}

static int sh_allocated(const char *ptr)

{

    return WITHIN_ARENA(ptr) ? 1 : 0;

}

static char *sh_find_my_buddy(char *ptr, int list)

{

    size_t bit;

    char *chunk = NULL;

    bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list);

    bit ^= 1;

    if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit))

        chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list));

    return chunk;

}

static void *sh_malloc(size_t size)

{

    ossl_ssize_t list, slist;

    size_t i;

    char *chunk;

    if (size > sh.arena_size)

        return NULL;

    list = sh.freelist_size - 1;

    for (i = sh.minsize; i < size; i <<= 1)

        list--;

    if (list < 0)

        return NULL;

    /* try to find a larger entry to split */

    for (slist = list; slist >= 0; slist--)

        if (sh.freelist[slist] != NULL)

            break;

    if (slist < 0)

        return NULL;

    /* split larger entry */

    while (slist != list) {

        char *temp = sh.freelist[slist];

        /* remove from bigger list */

        OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));

        sh_clearbit(temp, slist, sh.bittable);

        sh_remove_from_list(temp);

        OPENSSL_assert(temp != sh.freelist[slist]);

        /* done with bigger list */

        slist++;

        /* add to smaller list */

        OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));

        sh_setbit(temp, slist, sh.bittable);

        sh_add_to_list(&sh.freelist[slist], temp);

        OPENSSL_assert(sh.freelist[slist] == temp);

        /* split in 2 */

        temp += sh.arena_size >> slist;

        OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));

        sh_setbit(temp, slist, sh.bittable);

        sh_add_to_list(&sh.freelist[slist], temp);

        OPENSSL_assert(sh.freelist[slist] == temp);

        OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist));

    }

    /* peel off memory to hand back */

    chunk = sh.freelist[list];

    OPENSSL_assert(sh_testbit(chunk, list, sh.bittable));

    sh_setbit(chunk, list, sh.bitmalloc);

    sh_remove_from_list(chunk);

    OPENSSL_assert(WITHIN_ARENA(chunk));

    /* zero the free list header as a precaution against information leakage */

    memset(chunk, 0, sizeof(SH_LIST));

    return chunk;

}

static void sh_free(void *ptr)

{

    size_t list;

    void *buddy;

    if (ptr == NULL)

        return;

    OPENSSL_assert(WITHIN_ARENA(ptr));

    if (!WITHIN_ARENA(ptr))

        return;

    list = sh_getlist(ptr);

    OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));

    sh_clearbit(ptr, list, sh.bitmalloc);

    sh_add_to_list(&sh.freelist[list], ptr);

    /* Try to coalesce two adjacent free areas. */

    while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) {

        OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list));

        OPENSSL_assert(ptr != NULL);

        OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));

        sh_clearbit(ptr, list, sh.bittable);

        sh_remove_from_list(ptr);

        OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));

        sh_clearbit(buddy, list, sh.bittable);

        sh_remove_from_list(buddy);

        list--;

        /* Zero the higher addressed block's free list pointers */

        memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST));

        if (ptr > buddy)

            ptr = buddy;

        OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));

        sh_setbit(ptr, list, sh.bittable);

        sh_add_to_list(&sh.freelist[list], ptr);

        OPENSSL_assert(sh.freelist[list] == ptr);

    }

}

static size_t sh_actual_size(char *ptr)

{

    int list;

    OPENSSL_assert(WITHIN_ARENA(ptr));

    if (!WITHIN_ARENA(ptr))

        return 0;

    list = sh_getlist(ptr);

    OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));

    return sh.arena_size / (ONE << list);

}

#endif /* IMPLEMENTED */