md4.c

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/** A local MD4 implementation
 *
 * @note license is LGPL, but largely derived from a public domain source.
 *
 * @file src/lib/util/md4.c
 */
RCSID("$Id: 774f74e3d49871113aa756137cf339b959d75be2 $")
 
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/strerror.h>
#include <freeradius-devel/util/atexit.h>
 
/*
 *  FORCE MD4 TO USE OUR MD4 HEADER FILE!
 *  If we don't do this, it might pick up the systems broken MD4.
 */
#include <freeradius-devel/util/md4.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_md4_ctx_t    *md_ctx;
} fr_md4_free_list_t;
static _Thread_local fr_md4_free_list_t *md4_array;
 
static void fr_md4_local_ctx_reset(fr_md4_ctx_t *ctx);
static void fr_md4_local_ctx_copy(fr_md4_ctx_t *dst, fr_md4_ctx_t const *src);
#ifdef HAVE_OPENSSL_EVP_H
static fr_md4_ctx_t *fr_md4_local_ctx_init(void);
#else
static fr_md4_ctx_t *fr_md4_local_ctx_alloc(void);
#endif
static void fr_md4_local_ctx_free(fr_md4_ctx_t **ctx);
static void fr_md4_local_update(fr_md4_ctx_t *ctx, uint8_t const *in, size_t inlen);
static void fr_md4_local_final(uint8_t out[static MD4_DIGEST_LENGTH], fr_md4_ctx_t *ctx);
 
static fr_md4_funcs_t md4_local_funcs = {
        .reset = fr_md4_local_ctx_reset,
        .copy = fr_md4_local_ctx_copy,
#ifdef HAVE_OPENSSL_EVP_H
        .alloc = fr_md4_local_ctx_init,
#else
        .alloc = fr_md4_local_ctx_alloc,
#endif
        .free = fr_md4_local_ctx_free,
        .update = fr_md4_local_update,
        .final = fr_md4_local_final
};
fr_md4_funcs_t const *fr_md4_funcs = &md4_local_funcs;
 
/*
 *      If we have OpenSSL's EVP API available, then build wrapper functions.
 *
 *      We always need to build the local MD4 functions as OpenSSL could
 *      be operating in FIPS mode where MD4 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_md4_ctx_reset
 *
 */
static void fr_md4_openssl_ctx_reset(fr_md4_ctx_t *ctx)
{
        EVP_MD_CTX *md_ctx = ctx;
 
        EVP_MD_CTX_reset(md_ctx);
        EVP_DigestInit_ex(md_ctx, EVP_md4(), NULL);
}
 
/** @copydoc fr_md4_ctx_copy
 *
 */
static void fr_md4_openssl_ctx_copy(fr_md4_ctx_t *dst, fr_md4_ctx_t const *src)
{
        EVP_MD_CTX_copy_ex(dst, src);
}
 
/** @copydoc fr_md4_ctx_alloc
 *
 */
static fr_md4_ctx_t *fr_md4_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_md4(), NULL) != 1) {
                char buffer[256];
 
                ERR_error_string_n(ERR_get_error(), buffer, sizeof(buffer));
                fr_strerror_printf("Failed initialising md4 ctx: %s", buffer);
                EVP_MD_CTX_free(md_ctx);
 
                return NULL;
        }
 
        return md_ctx;
}
 
/** @copydoc fr_md4_ctx_free
 *
 */
static void fr_md4_openssl_ctx_free(fr_md4_ctx_t **ctx)
{
        EVP_MD_CTX_free(*ctx);
        *ctx = NULL;
}
 
/** @copydoc fr_md4_update
 *
 */
static void fr_md4_openssl_update(fr_md4_ctx_t *ctx, uint8_t const *in, size_t inlen)
{
        EVP_DigestUpdate(ctx, in, inlen);
}
 
/** @copydoc fr_md4_final
 *
 */
static void fr_md4_openssl_final(uint8_t out[static MD4_DIGEST_LENGTH], fr_md4_ctx_t *ctx)
{
        unsigned int len;
 
        EVP_DigestFinal(ctx, out, &len);
 
        if (!fr_cond_assert(len == MD4_DIGEST_LENGTH)) return;
}
 
static fr_md4_funcs_t md4_openssl_funcs = {
        .reset = fr_md4_openssl_ctx_reset,
        .copy = fr_md4_openssl_ctx_copy,
        .alloc = fr_md4_openssl_ctx_alloc,
        .free = fr_md4_openssl_ctx_free,
        .update = fr_md4_openssl_update,
        .final = fr_md4_openssl_final
};
#endif
 
/*
 * This code implements the MD4 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.
 * Todd C. Miller modified the md4 code to do MD4 based on RFC 1186.
 *
 * 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
 * MD4Context structure, pass it to fr_md4_init, call fr_md4_update as
 * needed on buffers full of bytes, and then call fr_md4_final, which
 * will fill a supplied 16-byte array with the digest.
 */
#ifndef WORDS_BIGENDIAN
#  define htole32_4(buf)                /* Nothing */
#  define htole32_14(buf)               /* Nothing */
#  define htole32_16(buf)               /* Nothing */
#else
/* Sometimes defined by endian.h */
#  ifndef htole32
#    define htole32(x)\
        (((((uint32_t)x) & 0xff000000) >> 24) |\
        ((((uint32_t)x) & 0x00ff0000) >> 8) |\
        ((((uint32_t)x) & 0x0000ff00) << 8) |\
        ((((uint32_t)x) & 0x000000ff) << 24))
#  endif
#  define htole32_4(buf) do {\
        (buf)[0] = htole32((buf)[0]);\
        (buf)[1] = htole32((buf)[1]);\
        (buf)[2] = htole32((buf)[2]);\
        (buf)[3] = htole32((buf)[3]);\
} while (0)
 
#  define htole32_14(buf) do {\
        (buf)[0] = htole32((buf)[0]);\
        (buf)[1] = htole32((buf)[1]);\
        (buf)[2] = htole32((buf)[2]);\
        (buf)[3] = htole32((buf)[3]);\
        (buf)[4] = htole32((buf)[4]);\
        (buf)[5] = htole32((buf)[5]);\
        (buf)[6] = htole32((buf)[6]);\
        (buf)[7] = htole32((buf)[7]);\
        (buf)[8] = htole32((buf)[8]);\
        (buf)[9] = htole32((buf)[9]);\
        (buf)[10] = htole32((buf)[10]);\
        (buf)[11] = htole32((buf)[11]);\
        (buf)[12] = htole32((buf)[12]);\
        (buf)[13] = htole32((buf)[13]);\
} while (0)
 
#  define htole32_16(buf) do {\
        (buf)[0] = htole32((buf)[0]);\
        (buf)[1] = htole32((buf)[1]);\
        (buf)[2] = htole32((buf)[2]);\
        (buf)[3] = htole32((buf)[3]);\
        (buf)[4] = htole32((buf)[4]);\
        (buf)[5] = htole32((buf)[5]);\
        (buf)[6] = htole32((buf)[6]);\
        (buf)[7] = htole32((buf)[7]);\
        (buf)[8] = htole32((buf)[8]);\
        (buf)[9] = htole32((buf)[9]);\
        (buf)[10] = htole32((buf)[10]);\
        (buf)[11] = htole32((buf)[11]);\
        (buf)[12] = htole32((buf)[12]);\
        (buf)[13] = htole32((buf)[13]);\
        (buf)[14] = htole32((buf)[14]);\
        (buf)[15] = htole32((buf)[15]);\
} while (0)
#endif
 
#define MD4_BLOCK_LENGTH 64
 
/* The three core functions - F1 is optimized somewhat */
#define MD4_F1(x, y, z) (z ^ (x & (y ^ z)))
#define MD4_F2(x, y, z) ((x & y) | (x & z) | (y & z))
#define MD4_F3(x, y, z) (x ^ y ^ z)
 
/* This is the central step in the MD4 algorithm. */
#define MD4STEP(f, w, x, y, z, data, s) (w += f(x, y, z) + data, w = w << s | w >> (32 - s))
 
/** The core of the MD4 algorithm
 *
 * This alters an existing MD4 hash to reflect the addition of 16
 * longwords of new data.  fr_md4_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 MD4 digest block to update.
 */
static void fr_md4_local_transform(uint32_t state[static 4], uint8_t const block[static MD4_BLOCK_LENGTH])
{
        uint32_t a, b, c, d;
        uint32_t const *in = (uint32_t const *)block;
 
        a = state[0];
        b = state[1];
        c = state[2];
        d = state[3];
 
        MD4STEP(MD4_F1, a, b, c, d, in[ 0],  3);
        MD4STEP(MD4_F1, d, a, b, c, in[ 1],  7);
        MD4STEP(MD4_F1, c, d, a, b, in[ 2], 11);
        MD4STEP(MD4_F1, b, c, d, a, in[ 3], 19);
        MD4STEP(MD4_F1, a, b, c, d, in[ 4],  3);
        MD4STEP(MD4_F1, d, a, b, c, in[ 5],  7);
        MD4STEP(MD4_F1, c, d, a, b, in[ 6], 11);
        MD4STEP(MD4_F1, b, c, d, a, in[ 7], 19);
        MD4STEP(MD4_F1, a, b, c, d, in[ 8],  3);
        MD4STEP(MD4_F1, d, a, b, c, in[ 9],  7);
        MD4STEP(MD4_F1, c, d, a, b, in[10], 11);
        MD4STEP(MD4_F1, b, c, d, a, in[11], 19);
        MD4STEP(MD4_F1, a, b, c, d, in[12],  3);
        MD4STEP(MD4_F1, d, a, b, c, in[13],  7);
        MD4STEP(MD4_F1, c, d, a, b, in[14], 11);
        MD4STEP(MD4_F1, b, c, d, a, in[15], 19);
 
        MD4STEP(MD4_F2, a, b, c, d, in[ 0] + 0x5a827999,  3);
        MD4STEP(MD4_F2, d, a, b, c, in[ 4] + 0x5a827999,  5);
        MD4STEP(MD4_F2, c, d, a, b, in[ 8] + 0x5a827999,  9);
        MD4STEP(MD4_F2, b, c, d, a, in[12] + 0x5a827999, 13);
        MD4STEP(MD4_F2, a, b, c, d, in[ 1] + 0x5a827999,  3);
        MD4STEP(MD4_F2, d, a, b, c, in[ 5] + 0x5a827999,  5);
        MD4STEP(MD4_F2, c, d, a, b, in[ 9] + 0x5a827999,  9);
        MD4STEP(MD4_F2, b, c, d, a, in[13] + 0x5a827999, 13);
        MD4STEP(MD4_F2, a, b, c, d, in[ 2] + 0x5a827999,  3);
        MD4STEP(MD4_F2, d, a, b, c, in[ 6] + 0x5a827999,  5);
        MD4STEP(MD4_F2, c, d, a, b, in[10] + 0x5a827999,  9);
        MD4STEP(MD4_F2, b, c, d, a, in[14] + 0x5a827999, 13);
        MD4STEP(MD4_F2, a, b, c, d, in[ 3] + 0x5a827999,  3);
        MD4STEP(MD4_F2, d, a, b, c, in[ 7] + 0x5a827999,  5);
        MD4STEP(MD4_F2, c, d, a, b, in[11] + 0x5a827999,  9);
        MD4STEP(MD4_F2, b, c, d, a, in[15] + 0x5a827999, 13);
 
        MD4STEP(MD4_F3, a, b, c, d, in[ 0] + 0x6ed9eba1,  3);
        MD4STEP(MD4_F3, d, a, b, c, in[ 8] + 0x6ed9eba1,  9);
        MD4STEP(MD4_F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
        MD4STEP(MD4_F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
        MD4STEP(MD4_F3, a, b, c, d, in[ 2] + 0x6ed9eba1,  3);
        MD4STEP(MD4_F3, d, a, b, c, in[10] + 0x6ed9eba1,  9);
        MD4STEP(MD4_F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
        MD4STEP(MD4_F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
        MD4STEP(MD4_F3, a, b, c, d, in[ 1] + 0x6ed9eba1,  3);
        MD4STEP(MD4_F3, d, a, b, c, in[ 9] + 0x6ed9eba1,  9);
        MD4STEP(MD4_F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
        MD4STEP(MD4_F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
        MD4STEP(MD4_F3, a, b, c, d, in[ 3] + 0x6ed9eba1,  3);
        MD4STEP(MD4_F3, d, a, b, c, in[11] + 0x6ed9eba1,  9);
        MD4STEP(MD4_F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
        MD4STEP(MD4_F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);
 
        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
}
 
typedef struct {
        uint32_t state[4];                      //!< State.
        uint32_t count[2];                      //!< Number of bits, mod 2^64.
        uint8_t buffer[MD4_BLOCK_LENGTH];       //!< Input buffer.
} fr_md4_ctx_local_t;
 
/** @copydoc fr_md4_ctx_reset
 *
 */
static void fr_md4_local_ctx_reset(fr_md4_ctx_t *ctx)
{
        fr_md4_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md4_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;
}
 
/** @copydoc fr_md4_ctx_copy
 *
 */
static void fr_md4_local_ctx_copy(fr_md4_ctx_t *dst, fr_md4_ctx_t const *src)
{
        fr_md4_ctx_local_t const *ctx_local_src = talloc_get_type_abort_const(src, fr_md4_ctx_local_t);
        fr_md4_ctx_local_t *ctx_local_dst = talloc_get_type_abort(dst, fr_md4_ctx_local_t);
 
        memcpy(ctx_local_dst, ctx_local_src, sizeof(*ctx_local_dst));
}
 
/** @copydoc fr_md4_ctx_alloc
 *
 */
static fr_md4_ctx_t *fr_md4_local_ctx_alloc(void)
{
        fr_md4_ctx_local_t *ctx_local;
 
        ctx_local = talloc(NULL, fr_md4_ctx_local_t);
        if (unlikely(!ctx_local)) return NULL;
        fr_md4_local_ctx_reset(ctx_local);
 
        return ctx_local;
}
 
#ifdef HAVE_OPENSSL_EVP_H
/** Initialize whether or not we use the local allocator, or the OpenSSL one.
 *
 */
static fr_md4_ctx_t *fr_md4_local_ctx_init(void)
{
        /*
         *      If we are in FIPS mode, then use the local allocator.
         */
        if (!EVP_default_properties_is_fips_enabled(NULL)) {
                /*
                 *      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_md4_funcs = &md4_openssl_funcs;
        } else {
                md4_local_funcs.alloc = fr_md4_local_ctx_alloc; /* Don't call this (init) function again */
        }
 
        return fr_md4_ctx_alloc();
}
#endif
 
/** @copydoc fr_md4_ctx_free
 *
 */
static void fr_md4_local_ctx_free(fr_md4_ctx_t **ctx)
{
        talloc_free(*ctx);
        *ctx = NULL;
}
 
static const uint8_t *zero = (uint8_t[]){ 0x00 };
 
/** @copydoc fr_md4_update
 *
 */
static void fr_md4_local_update(fr_md4_ctx_t *ctx, uint8_t const *in, size_t inlen)
{
        uint32_t                count;
        fr_md4_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md4_ctx_local_t);
 
        /*
         *      Needed so we can calculate the zero
         *      length md4 hash correctly.
         *      ubsan doesn't like arithmetic on
         *      NULL pointers.
         */
        if (!in) {
                in = zero;
                inlen = 0;
        }
 
        /* Bytes already stored in ctx_local->buffer */
        count = (uint32_t)((ctx_local->count[0] >> 3) & 0x3f);
 
        /* 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);
 
        /* Handle any leading odd-sized chunks */
        if (count) {
                unsigned char *p = (unsigned char *)ctx_local->buffer + count;
 
                count = MD4_BLOCK_LENGTH - count;
                if (inlen < count) {
                        memcpy(p, in, inlen);
                        return;
                }
                memcpy(p, in, count);
                htole32_16((uint32_t *)ctx_local->buffer);
                fr_md4_local_transform(ctx_local->state, ctx_local->buffer);
                in += count;
                inlen -= count;
        }
 
        /* Process data in MD4_BLOCK_LENGTH-byte chunks */
        while (inlen >= MD4_BLOCK_LENGTH) {
                memcpy(ctx_local->buffer, in, MD4_BLOCK_LENGTH);
                htole32_16((uint32_t *)ctx_local->buffer);
                fr_md4_local_transform(ctx_local->state, ctx_local->buffer);
                in += MD4_BLOCK_LENGTH;
                inlen -= MD4_BLOCK_LENGTH;
        }
 
        /* Handle any remaining bytes of data. */
        memcpy(ctx_local->buffer, in, inlen);
}
 
/** @copydoc fr_md4_final
 *
 */
static void fr_md4_local_final(uint8_t out[static MD4_DIGEST_LENGTH], fr_md4_ctx_t *ctx)
{
        uint32_t                count;
        unsigned char           *p;
        fr_md4_ctx_local_t      *ctx_local = talloc_get_type_abort(ctx, fr_md4_ctx_local_t);
 
        /* number of bytes mod 64 */
        count = (uint32_t)(ctx_local->count[0] >> 3) & 0x3f;
 
        /*
         * Set the first char of padding to 0x80.
         * This is safe since there is always at least one byte free.
         */
        p = ctx_local->buffer + count;
        *p++ = 0x80;
 
        /* Bytes of padding needed to make 64 bytes */
        count = 64 - 1 - count;
 
        /* Pad out to 56 mod 64 */
        if (count < 8) {
                /* Two lots of padding:  Pad the first block to 64 bytes */
                memset(p, 0, count);
                htole32_16((uint32_t *)ctx_local->buffer);
                fr_md4_local_transform(ctx_local->state, ctx_local->buffer);
 
                /* Now fill the next block with 56 bytes */
                memset(ctx_local->buffer, 0, 56);
        } else {
                /* Pad block to 56 bytes */
                memset(p, 0, count - 8);
        }
        htole32_14((uint32_t *)ctx_local->buffer);
 
        /* Append bit count and transform */
        ((uint32_t *)ctx_local->buffer)[14] = ctx_local->count[0];
        ((uint32_t *)ctx_local->buffer)[15] = ctx_local->count[1];
 
        fr_md4_local_transform(ctx_local->state, ctx_local->buffer);
        htole32_4(ctx_local->state);
        memcpy(out, ctx_local->state, MD4_DIGEST_LENGTH);
        memset(ctx_local, 0, sizeof(*ctx_local));       /* in case it's sensitive */
}
 
/*
 *      Digest function pointers
 */
fr_md4_ctx_reset_t fr_md4_ctx_reset = fr_md4_local_ctx_reset;
fr_md4_ctx_copy_t fr_md4_ctx_copy = fr_md4_local_ctx_copy;
fr_md4_ctx_alloc_t fr_md4_ctx_alloc = fr_md4_local_ctx_alloc;
fr_md4_ctx_free_t fr_md4_ctx_free = fr_md4_local_ctx_free;
fr_md4_update_t fr_md4_update = fr_md4_local_update;
fr_md4_final_t fr_md4_final = fr_md4_local_final;
 
/** Calculate the MD4 hash of the contents of a buffer
 *
 * @param[out] out Where to write the MD4 digest. Must be a minimum of MD4_DIGEST_LENGTH.
 * @param[in] in Data to hash.
 * @param[in] inlen Length of the data.
 */
void fr_md4_calc(uint8_t out[static MD4_DIGEST_LENGTH], uint8_t const *in, size_t inlen)
{
        fr_md4_ctx_t *ctx;
 
        ctx = fr_md4_ctx_alloc_from_list();
        fr_md4_update(ctx, in, inlen);
        fr_md4_final(out, ctx);
        fr_md4_ctx_free_from_list(&ctx);
}
 
static int _md4_ctx_free_on_exit(void *arg)
{
        int i;
        fr_md4_free_list_t *free_list = arg;
 
        for (i = 0; i < ARRAY_SIZE; i++) {
                if (free_list[i].used) continue;
 
                fr_md4_ctx_free(&free_list[i].md_ctx);
        }
        return talloc_free(free_list);
}
 
/** @copydoc fr_md4_ctx_alloc
 *
 */
fr_md4_ctx_t *fr_md4_ctx_alloc_from_list(void)
{
        int                     i;
        fr_md4_ctx_t            *md_ctx;
        fr_md4_free_list_t      *free_list;
 
        if (unlikely(!md4_array)) {
                free_list = talloc_zero_array(NULL, fr_md4_free_list_t, ARRAY_SIZE);
                if (unlikely(!free_list)) {
                oom:
                        fr_strerror_const("Out of Memory");
                        return NULL;
                }
 
                fr_atexit_thread_local(md4_array, _md4_ctx_free_on_exit, free_list);
 
                /*
                 *      Initialize all md4 contexts
                 */
                for (i = 0; i < ARRAY_SIZE; i++) {
                        md_ctx = fr_md4_ctx_alloc();
                        if (unlikely(md_ctx == NULL)) goto oom;
 
                        free_list[i].md_ctx = md_ctx;
                }
        } else {
                free_list = md4_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_md4_ctx_alloc();
}
 
/** @copydoc fr_md4_ctx_free
 *
 */
void fr_md4_ctx_free_from_list(fr_md4_ctx_t **ctx)
{
        int i;
        fr_md4_free_list_t *free_list = md4_array;
 
        if (free_list) {
                for (i = 0; i < ARRAY_SIZE; i++) {
                        if (free_list[i].md_ctx == *ctx) {
                                free_list[i].used = false;
                                fr_md4_ctx_reset(*ctx);
                                *ctx = NULL;
                                return;
                        }
                }
        }
 
        fr_md4_ctx_free(*ctx);
        *ctx = NULL;
}