


#include "internal/deprecated.h"

#include "internal/constant_time.h"

#include <stdio.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>

#include <openssl/prov_ssl.h>
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include "internal/cryptlib.h"
#include "crypto/rsa.h"
#include "rsa_local.h"


int RSA_padding_add_PKCS1_type_1(unsigned char *to, int tlen,
                                 const unsigned char *from, int flen)
{
    int j;
    unsigned char *p;

    if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {
        ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
        return 0;
    }

    p = (unsigned char *)to;

    *(p++) = 0;
    *(p++) = 1;                 

    
    j = tlen - 3 - flen;
    memset(p, 0xff, j);
    p += j;
    *(p++) = '\0';
    memcpy(p, from, (unsigned int)flen);
    return 1;
}

int RSA_padding_check_PKCS1_type_1(unsigned char *to, int tlen,
                                   const unsigned char *from, int flen,
                                   int num)
{
    int i, j;
    const unsigned char *p;

    p = from;

    

    if (num < RSA_PKCS1_PADDING_SIZE)
        return -1;

    
    if (num == flen) {
        if ((*p++) != 0x00) {
            ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_PADDING);
            return -1;
        }
        flen--;
    }

    if ((num != (flen + 1)) || (*(p++) != 0x01)) {
        ERR_raise(ERR_LIB_RSA, RSA_R_BLOCK_TYPE_IS_NOT_01);
        return -1;
    }

    
    j = flen - 1;               
    for (i = 0; i < j; i++) {
        if (*p != 0xff) {       
            if (*p == 0) {
                p++;
                break;
            } else {
                ERR_raise(ERR_LIB_RSA, RSA_R_BAD_FIXED_HEADER_DECRYPT);
                return -1;
            }
        }
        p++;
    }

    if (i == j) {
        ERR_raise(ERR_LIB_RSA, RSA_R_NULL_BEFORE_BLOCK_MISSING);
        return -1;
    }

    if (i < 8) {
        ERR_raise(ERR_LIB_RSA, RSA_R_BAD_PAD_BYTE_COUNT);
        return -1;
    }
    i++;                        
    j -= i;
    if (j > tlen) {
        ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE);
        return -1;
    }
    memcpy(to, p, (unsigned int)j);

    return j;
}

int ossl_rsa_padding_add_PKCS1_type_2_ex(OSSL_LIB_CTX *libctx, unsigned char *to,
                                         int tlen, const unsigned char *from,
                                         int flen)
{
    int i, j;
    unsigned char *p;

    if (flen > (tlen - RSA_PKCS1_PADDING_SIZE)) {
        ERR_raise(ERR_LIB_RSA, RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
        return 0;
    } else if (flen < 0) {
        ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_LENGTH);
        return 0;
    }

    p = (unsigned char *)to;

    *(p++) = 0;
    *(p++) = 2;                 

    
    j = tlen - 3 - flen;

    if (RAND_bytes_ex(libctx, p, j, 0) <= 0)
        return 0;
    for (i = 0; i < j; i++) {
        if (*p == '\0')
            do {
                if (RAND_bytes_ex(libctx, p, 1, 0) <= 0)
                    return 0;
            } while (*p == '\0');
        p++;
    }

    *(p++) = '\0';

    memcpy(p, from, (unsigned int)flen);
    return 1;
}

int RSA_padding_add_PKCS1_type_2(unsigned char *to, int tlen,
                                 const unsigned char *from, int flen)
{
    return ossl_rsa_padding_add_PKCS1_type_2_ex(NULL, to, tlen, from, flen);
}

int RSA_padding_check_PKCS1_type_2(unsigned char *to, int tlen,
                                   const unsigned char *from, int flen,
                                   int num)
{
    int i;
    
    unsigned char *em = NULL;
    unsigned int good, found_zero_byte, mask;
    int zero_index = 0, msg_index, mlen = -1;

    if (tlen <= 0 || flen <= 0)
        return -1;

    

    if (flen > num || num < RSA_PKCS1_PADDING_SIZE) {
        ERR_raise(ERR_LIB_RSA, RSA_R_PKCS_DECODING_ERROR);
        return -1;
    }

    em = OPENSSL_malloc(num);
    if (em == NULL)
        return -1;
    
    for (from += flen, em += num, i = 0; i < num; i++) {
        mask = ~constant_time_is_zero(flen);
        flen -= 1 & mask;
        from -= 1 & mask;
        *--em = *from & mask;
    }

    good = constant_time_is_zero(em[0]);
    good &= constant_time_eq(em[1], 2);

    
    found_zero_byte = 0;
    for (i = 2; i < num; i++) {
        unsigned int equals0 = constant_time_is_zero(em[i]);

        zero_index = constant_time_select_int(~found_zero_byte & equals0,
                                              i, zero_index);
        found_zero_byte |= equals0;
    }

    
    good &= constant_time_ge(zero_index, 2 + 8);

    
    msg_index = zero_index + 1;
    mlen = num - msg_index;

    
    good &= constant_time_ge(tlen, mlen);

    
    tlen = constant_time_select_int(constant_time_lt(num - RSA_PKCS1_PADDING_SIZE, tlen),
                                    num - RSA_PKCS1_PADDING_SIZE, tlen);
    for (msg_index = 1; msg_index < num - RSA_PKCS1_PADDING_SIZE; msg_index <<= 1) {
        mask = ~constant_time_eq(msg_index & (num - RSA_PKCS1_PADDING_SIZE - mlen), 0);
        for (i = RSA_PKCS1_PADDING_SIZE; i < num - msg_index; i++)
            em[i] = constant_time_select_8(mask, em[i + msg_index], em[i]);
    }
    for (i = 0; i < tlen; i++) {
        mask = good & constant_time_lt(i, mlen);
        to[i] = constant_time_select_8(mask, em[i + RSA_PKCS1_PADDING_SIZE], to[i]);
    }

    OPENSSL_clear_free(em, num);
#ifndef FIPS_MODULE
    
    ERR_raise(ERR_LIB_RSA, RSA_R_PKCS_DECODING_ERROR);
    err_clear_last_constant_time(1 & good);
#endif

    return constant_time_select_int(good, mlen, -1);
}


static int ossl_rsa_prf(OSSL_LIB_CTX *ctx,
                        unsigned char *to, int tlen,
                        const char *label, int llen,
                        const unsigned char *kdk,
                        uint16_t bitlen)
{
    int pos;
    int ret = -1;
    uint16_t iter = 0;
    unsigned char be_iter[sizeof(iter)];
    unsigned char be_bitlen[sizeof(bitlen)];
    HMAC_CTX *hmac = NULL;
    EVP_MD *md = NULL;
    unsigned char hmac_out[SHA256_DIGEST_LENGTH];
    unsigned int md_len;

    if (tlen * 8 != bitlen) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        return ret;
    }

    be_bitlen[0] = (bitlen >> 8) & 0xff;
    be_bitlen[1] = bitlen & 0xff;

    hmac = HMAC_CTX_new();
    if (hmac == NULL) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    
    md = EVP_MD_fetch(ctx, "sha256", NULL);
    if (md == NULL) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    if (HMAC_Init_ex(hmac, kdk, SHA256_DIGEST_LENGTH, md, NULL) <= 0) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    for (pos = 0; pos < tlen; pos += SHA256_DIGEST_LENGTH, iter++) {
        if (HMAC_Init_ex(hmac, NULL, 0, NULL, NULL) <= 0) {
            ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
            goto err;
        }

        be_iter[0] = (iter >> 8) & 0xff;
        be_iter[1] = iter & 0xff;

        if (HMAC_Update(hmac, be_iter, sizeof(be_iter)) <= 0) {
            ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
            goto err;
        }
        if (HMAC_Update(hmac, (unsigned char *)label, llen) <= 0) {
            ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
            goto err;
        }
        if (HMAC_Update(hmac, be_bitlen, sizeof(be_bitlen)) <= 0) {
            ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
            goto err;
        }

        
        md_len = SHA256_DIGEST_LENGTH;
        if (pos + SHA256_DIGEST_LENGTH > tlen) {
            if (HMAC_Final(hmac, hmac_out, &md_len) <= 0) {
                ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
                goto err;
            }
            memcpy(to + pos, hmac_out, tlen - pos);
        } else {
            if (HMAC_Final(hmac, to + pos, &md_len) <= 0) {
                ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
                goto err;
            }
        }
    }

    ret = 0;

err:
    HMAC_CTX_free(hmac);
    EVP_MD_free(md);
    return ret;
}


int ossl_rsa_padding_check_PKCS1_type_2(OSSL_LIB_CTX *ctx,
                                        unsigned char *to, int tlen,
                                        const unsigned char *from, int flen,
                                        int num, unsigned char *kdk)
{

#define MAX_LEN_GEN_TRIES 128
    unsigned char *synthetic = NULL;
    int synthetic_length;
    uint16_t len_candidate;
    unsigned char candidate_lengths[MAX_LEN_GEN_TRIES * sizeof(len_candidate)];
    uint16_t len_mask;
    uint16_t max_sep_offset;
    int synth_msg_index = 0;
    int ret = -1;
    int i, j;
    unsigned int good, found_zero_byte;
    int zero_index = 0, msg_index;

    
    if (num != flen || tlen <= 0 || flen <= 0) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    
    synthetic = OPENSSL_malloc(flen);
    if (synthetic == NULL) {
        ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
        return -1;
    }

    if (ossl_rsa_prf(ctx, synthetic, flen, "message", 7, kdk, flen * 8) < 0)
        goto err;

    
    if (ossl_rsa_prf(ctx, candidate_lengths, sizeof(candidate_lengths),
                     "length", 6, kdk,
                     MAX_LEN_GEN_TRIES * sizeof(len_candidate) * 8) < 0)
        goto err;

    
    len_mask = max_sep_offset = flen - 2 - 8;
    
    len_mask |= len_mask >> 1;
    len_mask |= len_mask >> 2;
    len_mask |= len_mask >> 4;
    len_mask |= len_mask >> 8;

    synthetic_length = 0;
    for (i = 0; i < MAX_LEN_GEN_TRIES * (int)sizeof(len_candidate);
            i += sizeof(len_candidate)) {
        len_candidate = (candidate_lengths[i] << 8) | candidate_lengths[i + 1];
        len_candidate &= len_mask;

        synthetic_length = constant_time_select_int(
            constant_time_lt(len_candidate, max_sep_offset),
            len_candidate, synthetic_length);
    }

    synth_msg_index = flen - synthetic_length;

    
    good = constant_time_is_zero(from[0]);
    good &= constant_time_eq(from[1], 2);

    
    found_zero_byte = 0;
    for (i = 2; i < flen; i++) {
        unsigned int equals0 = constant_time_is_zero(from[i]);
        zero_index = constant_time_select_int(~found_zero_byte & equals0,
                                              i, zero_index);
        found_zero_byte |= equals0;
    }

    
    good &= constant_time_ge(zero_index, 2 + 8);

    
    msg_index = zero_index + 1;

    
    good &= constant_time_ge(tlen, num - msg_index);

    msg_index = constant_time_select_int(good, msg_index, synth_msg_index);

    
    for (i = msg_index, j = 0; i < flen && j < tlen; i++, j++)
        to[j] = constant_time_select_8(good, from[i], synthetic[i]);
    ret = j;

err:
    
    if (ret < 0)
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
    OPENSSL_free(synthetic);
    return ret;
}


int ossl_rsa_padding_check_PKCS1_type_2_TLS(OSSL_LIB_CTX *libctx,
                                            unsigned char *to, size_t tlen,
                                            const unsigned char *from,
                                            size_t flen, int client_version,
                                            int alt_version)
{
    unsigned int i, good, version_good;
    unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH];

    
    if (flen < RSA_PKCS1_PADDING_SIZE + SSL_MAX_MASTER_KEY_LENGTH
            || tlen < SSL_MAX_MASTER_KEY_LENGTH) {
        ERR_raise(ERR_LIB_RSA, RSA_R_PKCS_DECODING_ERROR);
        return -1;
    }

    
    if (RAND_priv_bytes_ex(libctx, rand_premaster_secret,
                           sizeof(rand_premaster_secret), 0) <= 0) {
        ERR_raise(ERR_LIB_RSA, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    good = constant_time_is_zero(from[0]);
    good &= constant_time_eq(from[1], 2);

    
    for (i = 2; i < flen - SSL_MAX_MASTER_KEY_LENGTH - 1; i++)
        good &= ~constant_time_is_zero_8(from[i]);
    good &= constant_time_is_zero_8(from[flen - SSL_MAX_MASTER_KEY_LENGTH - 1]);


    
    version_good =
        constant_time_eq(from[flen - SSL_MAX_MASTER_KEY_LENGTH],
                         (client_version >> 8) & 0xff);
    version_good &=
        constant_time_eq(from[flen - SSL_MAX_MASTER_KEY_LENGTH + 1],
                         client_version & 0xff);

    
    if (alt_version > 0) {
        unsigned int workaround_good;

        workaround_good =
            constant_time_eq(from[flen - SSL_MAX_MASTER_KEY_LENGTH],
                             (alt_version >> 8) & 0xff);
        workaround_good &=
            constant_time_eq(from[flen - SSL_MAX_MASTER_KEY_LENGTH + 1],
                             alt_version & 0xff);
        version_good |= workaround_good;
    }

    good &= version_good;


    
    for (i = 0; i < SSL_MAX_MASTER_KEY_LENGTH; i++) {
        to[i] =
            constant_time_select_8(good,
                                   from[flen - SSL_MAX_MASTER_KEY_LENGTH + i],
                                   rand_premaster_secret[i]);
    }

    

    return SSL_MAX_MASTER_KEY_LENGTH;
}
