| /* |
| * Privacy Enhanced Mail (PEM) decoding |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C) |
| |
| #include "mbedtls/pem.h" |
| #include "mbedtls/base64.h" |
| #include "mbedtls/des.h" |
| #include "mbedtls/aes.h" |
| #include "mbedtls/md.h" |
| #include "mbedtls/cipher.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.h" |
| |
| #include <string.h> |
| |
| #include "mbedtls/platform.h" |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| #include "psa/crypto.h" |
| #endif |
| |
| #if defined(MBEDTLS_MD_CAN_MD5) && \ |
| defined(MBEDTLS_CIPHER_MODE_CBC) && \ |
| (defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C)) |
| #define PEM_RFC1421 |
| #endif /* MBEDTLS_MD_CAN_MD5 && |
| MBEDTLS_CIPHER_MODE_CBC && |
| ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ |
| |
| #if defined(MBEDTLS_PEM_PARSE_C) |
| void mbedtls_pem_init(mbedtls_pem_context *ctx) |
| { |
| memset(ctx, 0, sizeof(mbedtls_pem_context)); |
| } |
| |
| #if defined(PEM_RFC1421) |
| /* |
| * Read a 16-byte hex string and convert it to binary |
| */ |
| static int pem_get_iv(const unsigned char *s, unsigned char *iv, |
| size_t iv_len) |
| { |
| size_t i, j, k; |
| |
| memset(iv, 0, iv_len); |
| |
| for (i = 0; i < iv_len * 2; i++, s++) { |
| if (*s >= '0' && *s <= '9') { |
| j = *s - '0'; |
| } else |
| if (*s >= 'A' && *s <= 'F') { |
| j = *s - '7'; |
| } else |
| if (*s >= 'a' && *s <= 'f') { |
| j = *s - 'W'; |
| } else { |
| return MBEDTLS_ERR_PEM_INVALID_ENC_IV; |
| } |
| |
| k = ((i & 1) != 0) ? j : j << 4; |
| |
| iv[i >> 1] = (unsigned char) (iv[i >> 1] | k); |
| } |
| |
| return 0; |
| } |
| |
| static int pem_pbkdf1(unsigned char *key, size_t keylen, |
| unsigned char *iv, |
| const unsigned char *pwd, size_t pwdlen) |
| { |
| mbedtls_md_context_t md5_ctx; |
| const mbedtls_md_info_t *md5_info; |
| unsigned char md5sum[16]; |
| size_t use_len; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_md_init(&md5_ctx); |
| |
| /* Prepare the context. (setup() errors gracefully on NULL info.) */ |
| md5_info = mbedtls_md_info_from_type(MBEDTLS_MD_MD5); |
| if ((ret = mbedtls_md_setup(&md5_ctx, md5_info, 0)) != 0) { |
| goto exit; |
| } |
| |
| /* |
| * key[ 0..15] = MD5(pwd || IV) |
| */ |
| if ((ret = mbedtls_md_starts(&md5_ctx)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_update(&md5_ctx, pwd, pwdlen)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_update(&md5_ctx, iv, 8)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_finish(&md5_ctx, md5sum)) != 0) { |
| goto exit; |
| } |
| |
| if (keylen <= 16) { |
| memcpy(key, md5sum, keylen); |
| goto exit; |
| } |
| |
| memcpy(key, md5sum, 16); |
| |
| /* |
| * key[16..23] = MD5(key[ 0..15] || pwd || IV]) |
| */ |
| if ((ret = mbedtls_md_starts(&md5_ctx)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_update(&md5_ctx, md5sum, 16)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_update(&md5_ctx, pwd, pwdlen)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_update(&md5_ctx, iv, 8)) != 0) { |
| goto exit; |
| } |
| if ((ret = mbedtls_md_finish(&md5_ctx, md5sum)) != 0) { |
| goto exit; |
| } |
| |
| use_len = 16; |
| if (keylen < 32) { |
| use_len = keylen - 16; |
| } |
| |
| memcpy(key + 16, md5sum, use_len); |
| |
| exit: |
| mbedtls_md_free(&md5_ctx); |
| mbedtls_platform_zeroize(md5sum, 16); |
| |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_DES_C) |
| /* |
| * Decrypt with DES-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_des_decrypt(unsigned char des_iv[8], |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen) |
| { |
| mbedtls_des_context des_ctx; |
| unsigned char des_key[8]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_des_init(&des_ctx); |
| |
| if ((ret = pem_pbkdf1(des_key, 8, des_iv, pwd, pwdlen)) != 0) { |
| goto exit; |
| } |
| |
| if ((ret = mbedtls_des_setkey_dec(&des_ctx, des_key)) != 0) { |
| goto exit; |
| } |
| ret = mbedtls_des_crypt_cbc(&des_ctx, MBEDTLS_DES_DECRYPT, buflen, |
| des_iv, buf, buf); |
| |
| exit: |
| mbedtls_des_free(&des_ctx); |
| mbedtls_platform_zeroize(des_key, 8); |
| |
| return ret; |
| } |
| |
| /* |
| * Decrypt with 3DES-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_des3_decrypt(unsigned char des3_iv[8], |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen) |
| { |
| mbedtls_des3_context des3_ctx; |
| unsigned char des3_key[24]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_des3_init(&des3_ctx); |
| |
| if ((ret = pem_pbkdf1(des3_key, 24, des3_iv, pwd, pwdlen)) != 0) { |
| goto exit; |
| } |
| |
| if ((ret = mbedtls_des3_set3key_dec(&des3_ctx, des3_key)) != 0) { |
| goto exit; |
| } |
| ret = mbedtls_des3_crypt_cbc(&des3_ctx, MBEDTLS_DES_DECRYPT, buflen, |
| des3_iv, buf, buf); |
| |
| exit: |
| mbedtls_des3_free(&des3_ctx); |
| mbedtls_platform_zeroize(des3_key, 24); |
| |
| return ret; |
| } |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| /* |
| * Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_aes_decrypt(unsigned char aes_iv[16], unsigned int keylen, |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen) |
| { |
| mbedtls_aes_context aes_ctx; |
| unsigned char aes_key[32]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_aes_init(&aes_ctx); |
| |
| if ((ret = pem_pbkdf1(aes_key, keylen, aes_iv, pwd, pwdlen)) != 0) { |
| goto exit; |
| } |
| |
| if ((ret = mbedtls_aes_setkey_dec(&aes_ctx, aes_key, keylen * 8)) != 0) { |
| goto exit; |
| } |
| ret = mbedtls_aes_crypt_cbc(&aes_ctx, MBEDTLS_AES_DECRYPT, buflen, |
| aes_iv, buf, buf); |
| |
| exit: |
| mbedtls_aes_free(&aes_ctx); |
| mbedtls_platform_zeroize(aes_key, keylen); |
| |
| return ret; |
| } |
| #endif /* MBEDTLS_AES_C */ |
| |
| #if defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) |
| static int pem_check_pkcs_padding(unsigned char *input, size_t input_len, size_t *data_len) |
| { |
| /* input_len > 0 is guaranteed by mbedtls_pem_read_buffer(). */ |
| size_t pad_len = input[input_len - 1]; |
| size_t i; |
| |
| if (pad_len > input_len) { |
| return MBEDTLS_ERR_PEM_PASSWORD_MISMATCH; |
| } |
| |
| *data_len = input_len - pad_len; |
| |
| for (i = *data_len; i < input_len; i++) { |
| if (input[i] != pad_len) { |
| return MBEDTLS_ERR_PEM_PASSWORD_MISMATCH; |
| } |
| } |
| |
| return 0; |
| } |
| #endif /* MBEDTLS_DES_C || MBEDTLS_AES_C */ |
| |
| #endif /* PEM_RFC1421 */ |
| |
| int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const char *footer, |
| const unsigned char *data, const unsigned char *pwd, |
| size_t pwdlen, size_t *use_len) |
| { |
| int ret, enc; |
| size_t len; |
| unsigned char *buf; |
| const unsigned char *s1, *s2, *end; |
| #if defined(PEM_RFC1421) |
| unsigned char pem_iv[16]; |
| mbedtls_cipher_type_t enc_alg = MBEDTLS_CIPHER_NONE; |
| #else |
| ((void) pwd); |
| ((void) pwdlen); |
| #endif /* PEM_RFC1421 */ |
| |
| if (ctx == NULL) { |
| return MBEDTLS_ERR_PEM_BAD_INPUT_DATA; |
| } |
| |
| s1 = (unsigned char *) strstr((const char *) data, header); |
| |
| if (s1 == NULL) { |
| return MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; |
| } |
| |
| s2 = (unsigned char *) strstr((const char *) data, footer); |
| |
| if (s2 == NULL || s2 <= s1) { |
| return MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; |
| } |
| |
| s1 += strlen(header); |
| if (*s1 == ' ') { |
| s1++; |
| } |
| if (*s1 == '\r') { |
| s1++; |
| } |
| if (*s1 == '\n') { |
| s1++; |
| } else { |
| return MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; |
| } |
| |
| end = s2; |
| end += strlen(footer); |
| if (*end == ' ') { |
| end++; |
| } |
| if (*end == '\r') { |
| end++; |
| } |
| if (*end == '\n') { |
| end++; |
| } |
| *use_len = (size_t) (end - data); |
| |
| enc = 0; |
| |
| if (s2 - s1 >= 22 && memcmp(s1, "Proc-Type: 4,ENCRYPTED", 22) == 0) { |
| #if defined(PEM_RFC1421) |
| enc++; |
| |
| s1 += 22; |
| if (*s1 == '\r') { |
| s1++; |
| } |
| if (*s1 == '\n') { |
| s1++; |
| } else { |
| return MBEDTLS_ERR_PEM_INVALID_DATA; |
| } |
| |
| |
| #if defined(MBEDTLS_DES_C) |
| if (s2 - s1 >= 23 && memcmp(s1, "DEK-Info: DES-EDE3-CBC,", 23) == 0) { |
| enc_alg = MBEDTLS_CIPHER_DES_EDE3_CBC; |
| |
| s1 += 23; |
| if (s2 - s1 < 16 || pem_get_iv(s1, pem_iv, 8) != 0) { |
| return MBEDTLS_ERR_PEM_INVALID_ENC_IV; |
| } |
| |
| s1 += 16; |
| } else if (s2 - s1 >= 18 && memcmp(s1, "DEK-Info: DES-CBC,", 18) == 0) { |
| enc_alg = MBEDTLS_CIPHER_DES_CBC; |
| |
| s1 += 18; |
| if (s2 - s1 < 16 || pem_get_iv(s1, pem_iv, 8) != 0) { |
| return MBEDTLS_ERR_PEM_INVALID_ENC_IV; |
| } |
| |
| s1 += 16; |
| } |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| if (s2 - s1 >= 14 && memcmp(s1, "DEK-Info: AES-", 14) == 0) { |
| if (s2 - s1 < 22) { |
| return MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG; |
| } else if (memcmp(s1, "DEK-Info: AES-128-CBC,", 22) == 0) { |
| enc_alg = MBEDTLS_CIPHER_AES_128_CBC; |
| } else if (memcmp(s1, "DEK-Info: AES-192-CBC,", 22) == 0) { |
| enc_alg = MBEDTLS_CIPHER_AES_192_CBC; |
| } else if (memcmp(s1, "DEK-Info: AES-256-CBC,", 22) == 0) { |
| enc_alg = MBEDTLS_CIPHER_AES_256_CBC; |
| } else { |
| return MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG; |
| } |
| |
| s1 += 22; |
| if (s2 - s1 < 32 || pem_get_iv(s1, pem_iv, 16) != 0) { |
| return MBEDTLS_ERR_PEM_INVALID_ENC_IV; |
| } |
| |
| s1 += 32; |
| } |
| #endif /* MBEDTLS_AES_C */ |
| |
| if (enc_alg == MBEDTLS_CIPHER_NONE) { |
| return MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG; |
| } |
| |
| if (*s1 == '\r') { |
| s1++; |
| } |
| if (*s1 == '\n') { |
| s1++; |
| } else { |
| return MBEDTLS_ERR_PEM_INVALID_DATA; |
| } |
| #else |
| return MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE; |
| #endif /* PEM_RFC1421 */ |
| } |
| |
| if (s1 >= s2) { |
| return MBEDTLS_ERR_PEM_INVALID_DATA; |
| } |
| |
| ret = mbedtls_base64_decode(NULL, 0, &len, s1, (size_t) (s2 - s1)); |
| |
| if (ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER) { |
| return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PEM_INVALID_DATA, ret); |
| } |
| |
| if (len == 0) { |
| return MBEDTLS_ERR_PEM_BAD_INPUT_DATA; |
| } |
| |
| if ((buf = mbedtls_calloc(1, len)) == NULL) { |
| return MBEDTLS_ERR_PEM_ALLOC_FAILED; |
| } |
| |
| if ((ret = mbedtls_base64_decode(buf, len, &len, s1, (size_t) (s2 - s1))) != 0) { |
| mbedtls_zeroize_and_free(buf, len); |
| return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PEM_INVALID_DATA, ret); |
| } |
| |
| if (enc != 0) { |
| #if defined(PEM_RFC1421) |
| if (pwd == NULL) { |
| mbedtls_zeroize_and_free(buf, len); |
| return MBEDTLS_ERR_PEM_PASSWORD_REQUIRED; |
| } |
| |
| ret = 0; |
| |
| #if defined(MBEDTLS_DES_C) |
| if (enc_alg == MBEDTLS_CIPHER_DES_EDE3_CBC) { |
| ret = pem_des3_decrypt(pem_iv, buf, len, pwd, pwdlen); |
| } else if (enc_alg == MBEDTLS_CIPHER_DES_CBC) { |
| ret = pem_des_decrypt(pem_iv, buf, len, pwd, pwdlen); |
| } |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| if (enc_alg == MBEDTLS_CIPHER_AES_128_CBC) { |
| ret = pem_aes_decrypt(pem_iv, 16, buf, len, pwd, pwdlen); |
| } else if (enc_alg == MBEDTLS_CIPHER_AES_192_CBC) { |
| ret = pem_aes_decrypt(pem_iv, 24, buf, len, pwd, pwdlen); |
| } else if (enc_alg == MBEDTLS_CIPHER_AES_256_CBC) { |
| ret = pem_aes_decrypt(pem_iv, 32, buf, len, pwd, pwdlen); |
| } |
| #endif /* MBEDTLS_AES_C */ |
| |
| if (ret != 0) { |
| mbedtls_zeroize_and_free(buf, len); |
| return ret; |
| } |
| |
| /* Check PKCS padding and update data length based on padding info. |
| * This can be used to detect invalid padding data and password |
| * mismatches. */ |
| size_t unpadded_len; |
| ret = pem_check_pkcs_padding(buf, len, &unpadded_len); |
| if (ret != 0) { |
| mbedtls_zeroize_and_free(buf, len); |
| return ret; |
| } |
| len = unpadded_len; |
| #else |
| mbedtls_zeroize_and_free(buf, len); |
| return MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE; |
| #endif /* PEM_RFC1421 */ |
| } |
| |
| ctx->buf = buf; |
| ctx->buflen = len; |
| |
| return 0; |
| } |
| |
| void mbedtls_pem_free(mbedtls_pem_context *ctx) |
| { |
| if (ctx->buf != NULL) { |
| mbedtls_zeroize_and_free(ctx->buf, ctx->buflen); |
| } |
| mbedtls_free(ctx->info); |
| |
| mbedtls_platform_zeroize(ctx, sizeof(mbedtls_pem_context)); |
| } |
| #endif /* MBEDTLS_PEM_PARSE_C */ |
| |
| #if defined(MBEDTLS_PEM_WRITE_C) |
| int mbedtls_pem_write_buffer(const char *header, const char *footer, |
| const unsigned char *der_data, size_t der_len, |
| unsigned char *buf, size_t buf_len, size_t *olen) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *encode_buf = NULL, *c, *p = buf; |
| size_t len = 0, use_len, add_len = 0; |
| |
| mbedtls_base64_encode(NULL, 0, &use_len, der_data, der_len); |
| add_len = strlen(header) + strlen(footer) + (((use_len > 2) ? (use_len - 2) : 0) / 64) + 1; |
| |
| if (use_len + add_len > buf_len) { |
| *olen = use_len + add_len; |
| return MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL; |
| } |
| |
| if (use_len != 0 && |
| ((encode_buf = mbedtls_calloc(1, use_len)) == NULL)) { |
| return MBEDTLS_ERR_PEM_ALLOC_FAILED; |
| } |
| |
| if ((ret = mbedtls_base64_encode(encode_buf, use_len, &use_len, der_data, |
| der_len)) != 0) { |
| mbedtls_free(encode_buf); |
| return ret; |
| } |
| |
| memcpy(p, header, strlen(header)); |
| p += strlen(header); |
| c = encode_buf; |
| |
| while (use_len) { |
| len = (use_len > 64) ? 64 : use_len; |
| memcpy(p, c, len); |
| use_len -= len; |
| p += len; |
| c += len; |
| *p++ = '\n'; |
| } |
| |
| memcpy(p, footer, strlen(footer)); |
| p += strlen(footer); |
| |
| *p++ = '\0'; |
| *olen = (size_t) (p - buf); |
| |
| /* Clean any remaining data previously written to the buffer */ |
| memset(buf + *olen, 0, buf_len - *olen); |
| |
| mbedtls_free(encode_buf); |
| return 0; |
| } |
| #endif /* MBEDTLS_PEM_WRITE_C */ |
| #endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */ |