md5.c

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/** A local MD5 implementation
 *
 * @note license is LGPL, but largely derived from a public domain source.
 *
 * @file src/lib/util/md5.c
 */
RCSID("$Id: f0f12cababa84b8d644abad5470737f90710a899 $")
 
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/strerror.h>
#include <freeradius-devel/util/atexit.h>
 
/*
 *  FORCE MD5 TO USE OUR MD5 HEADER FILE!
 *  If we don't do this, it might pick up the systems broken MD5.
 */
#include <freeradius-devel/util/md5.h>
 
/** The thread local free list
 *
 * Any entries remaining in the list will be freed when the thread is joined
 */
#define ARRAY_SIZE (8)
typedef struct {
        bool            used;
        fr_md5_ctx_t    *md_ctx;
} fr_md5_free_list_t;
static _Thread_local fr_md5_free_list_t *md5_array;
 
static void fr_md5_local_ctx_reset(fr_md5_ctx_t *ctx);
static void fr_md5_local_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src);
static fr_md5_ctx_t *fr_md5_local_ctx_alloc(void);
static void fr_md5_local_ctx_free(fr_md5_ctx_t **ctx);
static void fr_md5_local_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen);
static void fr_md5_local_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx);
 
static fr_md5_funcs_t md5_local_funcs = {
        .reset = fr_md5_local_ctx_reset,
        .copy = fr_md5_local_ctx_copy,
        .alloc = fr_md5_local_ctx_alloc,
        .free = fr_md5_local_ctx_free,
        .update = fr_md5_local_update,
        .final = fr_md5_local_final
};
fr_md5_funcs_t const *fr_md5_funcs = &md5_local_funcs;
 
/*
 *      If we have OpenSSL's EVP API available, then build wrapper functions.
 *
 *      We always need to build the local MD5 functions as OpenSSL could
 *      be operating in FIPS mode where MD5 digest functions are unavailable.
 */
#ifdef HAVE_OPENSSL_EVP_H
#  include <freeradius-devel/tls/openssl_user_macros.h>
#  include <openssl/evp.h>
#  include <openssl/crypto.h>
#  include <openssl/err.h>
#  include <openssl/provider.h>
 
/** @copydoc fr_md5_ctx_reset
 *
 */
static void fr_md5_openssl_ctx_reset(fr_md5_ctx_t *ctx)
{
        EVP_MD_CTX *md_ctx = ctx;
 
        EVP_MD_CTX_reset(md_ctx);
        (void)EVP_DigestInit_ex(md_ctx, EVP_md5(), NULL);
}
 
/** @copydoc fr_md5_ctx_copy
 *
 */
static void fr_md5_openssl_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src)
{
        EVP_MD_CTX_copy_ex(dst, src);
}
 
/** @copydoc fr_md5_ctx_alloc
 *
 */
static fr_md5_ctx_t *fr_md5_openssl_ctx_alloc(void)
{
        EVP_MD_CTX *md_ctx;
 
        md_ctx = EVP_MD_CTX_new();
        if (unlikely(!md_ctx)) return NULL;
 
        if (EVP_DigestInit_ex(md_ctx, EVP_md5(), NULL) != 1) {
                char buffer[256];
 
                ERR_error_string_n(ERR_get_error(), buffer, sizeof(buffer));
                fr_strerror_printf("Failed initialising MD5 ctx: %s", buffer);
                EVP_MD_CTX_free(md_ctx);
 
                return NULL;
        }
 
        return md_ctx;
}
 
/** @copydoc fr_md5_ctx_free
 *
 */
static void fr_md5_openssl_ctx_free(fr_md5_ctx_t **ctx)
{
        EVP_MD_CTX_free(*ctx);
        *ctx = NULL;
}
 
/** @copydoc fr_md5_update
 *
 */
static void fr_md5_openssl_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen)
{
        EVP_DigestUpdate(ctx, in, inlen);
}
 
/** @copydoc fr_md5_final
 *
 */
static void fr_md5_openssl_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx)
{
        unsigned int len;
 
        EVP_DigestFinal(ctx, out, &len);
 
        if (!fr_cond_assert(len == MD5_DIGEST_LENGTH)) return;
}
 
static fr_md5_funcs_t md5_openssl_funcs = {
        .reset = fr_md5_openssl_ctx_reset,
        .copy = fr_md5_openssl_ctx_copy,
        .alloc = fr_md5_openssl_ctx_alloc,
        .free = fr_md5_openssl_ctx_free,
        .update = fr_md5_openssl_update,
        .final = fr_md5_openssl_final
};
#endif
 
#  define MD5_BLOCK_LENGTH 64
typedef struct {
        uint32_t state[4];                      //!< State.
        uint32_t count[2];                      //!< Number of bits, mod 2^64.
        uint8_t buffer[MD5_BLOCK_LENGTH];       //!< Input buffer.
} fr_md5_ctx_local_t;
 
/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to fr_md5_init, call fr_md5_update as
 * needed on buffers full of bytes, and then call fr_md5_final, which
 * will fill a supplied 16-byte array with the digest.
 */
#define PUT_64BIT_LE(cp, value) do {\
        (cp)[7] = (value)[1] >> 24;\
        (cp)[6] = (value)[1] >> 16;\
        (cp)[5] = (value)[1] >> 8;\
        (cp)[4] = (value)[1];\
        (cp)[3] = (value)[0] >> 24;\
        (cp)[2] = (value)[0] >> 16;\
        (cp)[1] = (value)[0] >> 8;\
        (cp)[0] = (value)[0];\
} while (0)
 
#define PUT_32BIT_LE(cp, value) do {\
        (cp)[3] = (value) >> 24;\
        (cp)[2] = (value) >> 16;\
        (cp)[1] = (value) >> 8;\
        (cp)[0] = (value);\
} while (0)
 
static const uint8_t PADDING[MD5_BLOCK_LENGTH] = {
        0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
 
 
/* The four core functions - MD5_F1 is optimized somewhat */
#define MD5_F1(x, y, z) (z ^ (x & (y ^ z)))
#define MD5_F2(x, y, z) MD5_F1(z, x, y)
#define MD5_F3(x, y, z) (x ^ y ^ z)
#define MD5_F4(x, y, z) (y ^ (x | ~z))
 
/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) (w += f(x, y, z) + data, w = w << s | w >> (32 - s),  w += x)
 
/** The core of the MD5 algorithm
 *
 * This alters an existing MD5 hash to reflect the addition of 16
 * longwords of new data.  fr_md5_update blocks the data and converts bytes
 * into longwords for this routine.
 *
 * @param[in] state 16 bytes of data to feed into the hashing function.
 * @param[in,out] block MD5 digest block to update.
 */
static void fr_md5_local_transform(uint32_t state[static 4], uint8_t const block[static MD5_BLOCK_LENGTH])
{
        uint32_t a, b, c, d, in[MD5_BLOCK_LENGTH / 4];
 
        for (a = 0; a < (MD5_BLOCK_LENGTH / 4); a++) {
                size_t idx = a * 4;
 
                in[a] = (uint32_t)(
                    (uint32_t)(block[idx + 0]) |
                    (uint32_t)(block[idx + 1]) <<  8 |
                    (uint32_t)(block[idx + 2]) << 16 |
                    (uint32_t)(block[idx + 3]) << 24);
        }
 
        a = state[0];
        b = state[1];
        c = state[2];
        d = state[3];
 
        MD5STEP(MD5_F1, a, b, c, d, in[ 0] + 0xd76aa478,  7);
        MD5STEP(MD5_F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
        MD5STEP(MD5_F1, c, d, a, b, in[ 2] + 0x242070db, 17);
        MD5STEP(MD5_F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
        MD5STEP(MD5_F1, a, b, c, d, in[ 4] + 0xf57c0faf,  7);
        MD5STEP(MD5_F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
        MD5STEP(MD5_F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
        MD5STEP(MD5_F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
        MD5STEP(MD5_F1, a, b, c, d, in[ 8] + 0x698098d8,  7);
        MD5STEP(MD5_F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
        MD5STEP(MD5_F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(MD5_F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(MD5_F1, a, b, c, d, in[12] + 0x6b901122,  7);
        MD5STEP(MD5_F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(MD5_F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(MD5_F1, b, c, d, a, in[15] + 0x49b40821, 22);
 
        MD5STEP(MD5_F2, a, b, c, d, in[ 1] + 0xf61e2562,  5);
        MD5STEP(MD5_F2, d, a, b, c, in[ 6] + 0xc040b340,  9);
        MD5STEP(MD5_F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(MD5_F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
        MD5STEP(MD5_F2, a, b, c, d, in[ 5] + 0xd62f105d,  5);
        MD5STEP(MD5_F2, d, a, b, c, in[10] + 0x02441453,  9);
        MD5STEP(MD5_F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(MD5_F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
        MD5STEP(MD5_F2, a, b, c, d, in[ 9] + 0x21e1cde6,  5);
        MD5STEP(MD5_F2, d, a, b, c, in[14] + 0xc33707d6,  9);
        MD5STEP(MD5_F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
        MD5STEP(MD5_F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
        MD5STEP(MD5_F2, a, b, c, d, in[13] + 0xa9e3e905,  5);
        MD5STEP(MD5_F2, d, a, b, c, in[ 2] + 0xfcefa3f8,  9);
        MD5STEP(MD5_F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
        MD5STEP(MD5_F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 
        MD5STEP(MD5_F3, a, b, c, d, in[ 5] + 0xfffa3942,  4);
        MD5STEP(MD5_F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
        MD5STEP(MD5_F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(MD5_F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(MD5_F3, a, b, c, d, in[ 1] + 0xa4beea44,  4);
        MD5STEP(MD5_F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
        MD5STEP(MD5_F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
        MD5STEP(MD5_F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(MD5_F3, a, b, c, d, in[13] + 0x289b7ec6,  4);
        MD5STEP(MD5_F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
        MD5STEP(MD5_F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
        MD5STEP(MD5_F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
        MD5STEP(MD5_F3, a, b, c, d, in[ 9] + 0xd9d4d039,  4);
        MD5STEP(MD5_F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(MD5_F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(MD5_F3, b, c, d, a, in[2 ] + 0xc4ac5665, 23);
 
        MD5STEP(MD5_F4, a, b, c, d, in[ 0] + 0xf4292244,  6);
        MD5STEP(MD5_F4, d, a, b, c, in[7 ] + 0x432aff97, 10);
        MD5STEP(MD5_F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(MD5_F4, b, c, d, a, in[5 ] + 0xfc93a039, 21);
        MD5STEP(MD5_F4, a, b, c, d, in[12] + 0x655b59c3,  6);
        MD5STEP(MD5_F4, d, a, b, c, in[3 ] + 0x8f0ccc92, 10);
        MD5STEP(MD5_F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(MD5_F4, b, c, d, a, in[1 ] + 0x85845dd1, 21);
        MD5STEP(MD5_F4, a, b, c, d, in[8 ] + 0x6fa87e4f,  6);
        MD5STEP(MD5_F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(MD5_F4, c, d, a, b, in[6 ] + 0xa3014314, 15);
        MD5STEP(MD5_F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(MD5_F4, a, b, c, d, in[4 ] + 0xf7537e82,  6);
        MD5STEP(MD5_F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(MD5_F4, c, d, a, b, in[2 ] + 0x2ad7d2bb, 15);
        MD5STEP(MD5_F4, b, c, d, a, in[9 ] + 0xeb86d391, 21);
 
        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
}
 
/** @copydoc fr_md5_ctx_reset
 *
 */
static void fr_md5_local_ctx_reset(fr_md5_ctx_t *ctx)
{
        fr_md5_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);
 
        ctx_local->count[0] = 0;
        ctx_local->count[1] = 0;
        ctx_local->state[0] = 0x67452301;
        ctx_local->state[1] = 0xefcdab89;
        ctx_local->state[2] = 0x98badcfe;
        ctx_local->state[3] = 0x10325476;
        memset(ctx_local->buffer, 0, sizeof(ctx_local->buffer));
}
 
/** @copydoc fr_md5_ctx_copy
 *
 */
static void fr_md5_local_ctx_copy(fr_md5_ctx_t *dst, fr_md5_ctx_t const *src)
{
        fr_md5_ctx_local_t const *ctx_local_src = talloc_get_type_abort_const(src, fr_md5_ctx_local_t);
        fr_md5_ctx_local_t *ctx_local_dst = talloc_get_type_abort(dst, fr_md5_ctx_local_t);
 
        memcpy(ctx_local_dst, ctx_local_src, sizeof(*ctx_local_dst));
}
 
/** @copydoc fr_md5_ctx_alloc
 *
 */
static fr_md5_ctx_t *fr_md5_local_ctx_alloc(void)
{
        fr_md5_ctx_local_t *ctx_local;
 
        ctx_local = talloc(NULL, fr_md5_ctx_local_t);
        if (unlikely(!ctx_local)) return NULL;
        fr_md5_local_ctx_reset(ctx_local);
 
        return ctx_local;
}
 
/** @copydoc fr_md5_ctx_free
 *
 */
static void fr_md5_local_ctx_free(fr_md5_ctx_t **ctx)
{
        talloc_free(*ctx);
        *ctx = NULL;
}
 
static const uint8_t *zero = (uint8_t[]){ 0x00 };
 
/** @copydoc fr_md5_update
 *
 */
static void fr_md5_local_update(fr_md5_ctx_t *ctx, uint8_t const *in, size_t inlen)
{
        fr_md5_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);
 
        size_t have, need;
 
        /*
         *      Needed so we can calculate the zero
         *      length md5 hash correctly.
         *      ubsan doesn't like arithmetic on
         *      NULL pointers.
         */
        if (!in) {
                in = zero;
                inlen = 0;
        }
 
        /* Check how many bytes we already have and how many more we need. */
        have = (size_t)((ctx_local->count[0] >> 3) & (MD5_BLOCK_LENGTH - 1));
        need = MD5_BLOCK_LENGTH - have;
 
        /* Update bitcount */
/*      ctx_local->count += (uint64_t)inlen << 3;*/
        if ((ctx_local->count[0] += ((uint32_t)inlen << 3)) < (uint32_t)inlen) {
        /* Overflowed ctx_local->count[0] */
                ctx_local->count[1]++;
        }
        ctx_local->count[1] += ((uint32_t)inlen >> 29);
 
        if (inlen >= need) {
                if (have != 0) {
                        memcpy(ctx_local->buffer + have, in, need);
                        fr_md5_local_transform(ctx_local->state, ctx_local->buffer);
                        in += need;
                        inlen -= need;
                        have = 0;
                }
 
                /* Process data in MD5_BLOCK_LENGTH-byte chunks. */
                while (inlen >= MD5_BLOCK_LENGTH) {
                        fr_md5_local_transform(ctx_local->state, in);
                        in += MD5_BLOCK_LENGTH;
                        inlen -= MD5_BLOCK_LENGTH;
                }
        }
 
        /* Handle any remaining bytes of data. */
        memcpy(ctx_local->buffer + have, in, inlen);
}
 
/** @copydoc fr_md5_final
 *
 */
static void fr_md5_local_final(uint8_t out[static MD5_DIGEST_LENGTH], fr_md5_ctx_t *ctx)
{
        fr_md5_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md5_ctx_local_t);
        uint8_t                 count[8];
        size_t                  padlen;
        int                     i;
 
        /* Convert count to 8 bytes in little endian order. */
        PUT_64BIT_LE(count, ctx_local->count);
 
        /* Pad out to 56 mod 64. */
        padlen = MD5_BLOCK_LENGTH -
            ((ctx_local->count[0] >> 3) & (MD5_BLOCK_LENGTH - 1));
        if (padlen < 1 + 8)
                padlen += MD5_BLOCK_LENGTH;
        fr_md5_update(ctx_local, PADDING, padlen - 8); /* padlen - 8 <= 64 */
        fr_md5_update(ctx_local, count, 8);
 
        for (i = 0; i < 4; i++)
                PUT_32BIT_LE(out + i * 4, ctx_local->state[i]);
 
        memset(ctx_local, 0, sizeof(*ctx_local));       /* in case it's sensitive */
}
 
/** Calculate the MD5 hash of the contents of a buffer
 *
 * @param[out] out Where to write the MD5 digest. Must be a minimum of MD5_DIGEST_LENGTH.
 * @param[in] in Data to hash.
 * @param[in] inlen Length of the data.
 */
void fr_md5_calc(uint8_t out[static MD5_DIGEST_LENGTH], uint8_t const *in, size_t inlen)
{
        fr_md5_ctx_t *ctx;
 
        ctx = fr_md5_ctx_alloc_from_list();
        fr_md5_update(ctx, in, inlen);
        fr_md5_final(out, ctx);
        fr_md5_ctx_free_from_list(&ctx);
}
 
static int _md5_ctx_free_on_exit(void *arg)
{
        int i;
        fr_md5_free_list_t *free_list = arg;
 
        for (i = 0; i < ARRAY_SIZE; i++) {
                if (free_list[i].used) continue;
 
                fr_md5_ctx_free(&free_list[i].md_ctx);
        }
        return talloc_free(free_list);
}
 
/** @copydoc fr_md5_ctx_alloc
 *
 */
fr_md5_ctx_t *fr_md5_ctx_alloc_from_list(void)
{
        int                     i;
        fr_md5_ctx_t            *md_ctx;
        fr_md5_free_list_t      *free_list;
 
        if (unlikely(!md5_array)) {
                free_list = talloc_zero_array(NULL, fr_md5_free_list_t, ARRAY_SIZE);
                if (unlikely(!free_list)) {
                oom:
                        fr_strerror_const("Out of Memory");
                        return NULL;
                }
 
                fr_atexit_thread_local(md5_array, _md5_ctx_free_on_exit, free_list);
 
                /*
                 *      Initialize all MD5 contexts
                 */
                for (i = 0; i < ARRAY_SIZE; i++) {
                        md_ctx = fr_md5_ctx_alloc();
                        if (unlikely(md_ctx == NULL)) goto oom;
 
                        free_list[i].md_ctx = md_ctx;
                }
        } else {
                free_list = md5_array;
        }
 
        for (i = 0; i < ARRAY_SIZE; i++) {
                if (free_list[i].used) continue;
 
                free_list[i].used = true;
                return free_list[i].md_ctx;
        }
 
        /*
         *      No more free contexts, just allocate a new one.
         */
        return fr_md5_ctx_alloc();
}
 
/** @copydoc fr_md5_ctx_free
 *
 */
void fr_md5_ctx_free_from_list(fr_md5_ctx_t **ctx)
{
        int i;
        fr_md5_free_list_t *free_list = md5_array;
 
        if (free_list) {
                for (i = 0; i < ARRAY_SIZE; i++) {
                        if (free_list[i].md_ctx == *ctx) {
                                free_list[i].used = false;
                                fr_md5_ctx_reset(*ctx);
                                *ctx = NULL;
                                return;
                        }
                }
        }
 
        fr_md5_ctx_free(*ctx);
        *ctx = NULL;
}
 
#ifdef HAVE_OPENSSL_EVP_H
void fr_md5_openssl_init(void)
{
        /*
         *      If we are in FIPS mode, then we still use the local
         *      allocator.
         */
        if (!EVP_default_properties_is_fips_enabled(NULL)) return;
 
        /*
         *      OpenSSL isn't in FIPS mode.  Swap out the functions
         *      pointers for the OpenSSL versions.
         *
         *      We do this by swapping out a pointer to a structure
         *      containing the functions, as this prevents possible
         *      skew where some threads see a mixture of functions.
         */
        fr_md5_funcs = &md5_openssl_funcs;
}
 
void fr_md5_openssl_free(void)
{
        fr_md5_funcs = &md5_local_funcs;
}
#endif