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Added Support for Password Authentication Using a Single Tile in Tight, Raw, and ZRLE Encodings
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,9 @@ | ||
| #pragma once | ||
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| #define CHALLENGESIZE 16 | ||
| #define KEYSIZE 8 | ||
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| struct nvnc_client; | ||
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| int vnc_auth_handle_message(struct nvnc_client* client); | ||
| void genRandomBytes(unsigned char *bytes); |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,193 @@ | ||
| #include <stdlib.h> | ||
| #include <stdbool.h> | ||
| #include <time.h> | ||
| #include "common.h" | ||
| #include "stream/stream.h" | ||
| #include "auth/auth.h" | ||
| #include "auth/vncauth.h" | ||
| #include <openssl/evp.h> | ||
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| static unsigned char reverseByte(unsigned char b) | ||
| { | ||
| b = (b & 0xF0) >> 4 | (b & 0x0F) << 4; | ||
| b = (b & 0xCC) >> 2 | (b & 0x33) << 2; | ||
| b = (b & 0xAA) >> 1 | (b & 0x55) << 1; | ||
| return b; | ||
| } | ||
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| int encrypt_des(void *encrypted, int *encrypted_len, const unsigned char deskey[8], const void *plain, const size_t plain_len) | ||
| { | ||
| int res = 0; | ||
| EVP_CIPHER_CTX *ctx; | ||
| unsigned char reversedKey[8]; | ||
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| for (int i = 0; i < 8; i++) | ||
| { | ||
| reversedKey[i] = reverseByte(deskey[i]); | ||
| } | ||
| if(!(ctx = EVP_CIPHER_CTX_new())) | ||
| { | ||
| nvnc_log(NVNC_LOG_ERROR, "EVP_CIPHER_CTX_new() failed"); | ||
| goto onFailure; | ||
| } | ||
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| if(!EVP_EncryptInit_ex(ctx, EVP_des_ecb(), NULL, reversedKey, NULL)) | ||
| { | ||
| nvnc_log(NVNC_LOG_ERROR, "EVP_EncryptInit_ex() failed"); | ||
| goto onFailure; | ||
| } | ||
| if(!EVP_EncryptUpdate(ctx, encrypted, encrypted_len, plain, plain_len)) | ||
| { | ||
| nvnc_log(NVNC_LOG_ERROR, "EVP_EncryptUpdate() failed"); | ||
| goto onFailure; | ||
| } | ||
| res = 1; | ||
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| onFailure: | ||
| EVP_CIPHER_CTX_free(ctx); | ||
| return res; | ||
| } | ||
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| void genRandomBytes(unsigned char *bytes) | ||
| { | ||
| if (!bytes) | ||
| return; | ||
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| static bool s_srandom_called = false; | ||
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| if (!s_srandom_called) | ||
| { | ||
| srandom((unsigned int)time(NULL) ^ (unsigned int)getpid()); | ||
| s_srandom_called = true; | ||
| } | ||
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| int i = 0; | ||
| for (i = 0; i < CHALLENGESIZE; i++) | ||
| { | ||
| bytes[i] = (unsigned char)(random() & 255); | ||
| nvnc_log(NVNC_LOG_DEBUG, "genRandomBytes: %u", bytes[i]); | ||
| } | ||
| } | ||
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| void encryptBytes(uint8_t *bytes, char *passwd) | ||
| { | ||
| if (!bytes) | ||
| return; | ||
| if (!passwd) | ||
| return; | ||
| unsigned char key[8]; | ||
| unsigned int i; | ||
| int out_len; | ||
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| /* key is simply password padded with nulls */ | ||
| for (i = 0; i < 8; i++) | ||
| { | ||
| if (i < strlen(passwd)) | ||
| { | ||
| key[i] = passwd[i]; | ||
| } | ||
| else | ||
| { | ||
| key[i] = 0; | ||
| } | ||
| } | ||
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| uint8_t newin[16]; | ||
| unsigned char encryptedPasswd[8]; | ||
| memcpy(newin, bytes, 16); | ||
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| uint8_t outBuf[CHALLENGESIZE]; | ||
| if(encrypt_des(bytes,&out_len, key, newin, CHALLENGESIZE ) != 1) | ||
| { | ||
| nvnc_log(NVNC_LOG_DEBUG, "encryptBytes failed"); | ||
| } | ||
| } | ||
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| bool compare_challenges(struct nvnc_client *cl, const char *response, int len) | ||
| { | ||
| nvnc_log(NVNC_LOG_DEBUG, "compare_challenges called"); | ||
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| if (!cl) | ||
| return false; | ||
| if (!response) | ||
| return false; | ||
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| char **passwds; | ||
| int i = 0; | ||
| uint8_t auth_tmp[CHALLENGESIZE]; | ||
| memcpy((char *)auth_tmp, (char *)cl->vnc_auth.challenge, CHALLENGESIZE); | ||
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| for (int i = 0; i < CHALLENGESIZE; i++) | ||
| { | ||
| nvnc_log(NVNC_LOG_DEBUG, "0x%02X ", auth_tmp[i]); | ||
| } | ||
| nvnc_log(NVNC_LOG_DEBUG, " password is: %s\n", cl->auth->password); | ||
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| encryptBytes(auth_tmp, cl->auth->password); | ||
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| if (memcmp(auth_tmp, response, len) == 0) | ||
| { | ||
| nvnc_log(NVNC_LOG_DEBUG, "Password comparision passed"); | ||
| return true; | ||
| } | ||
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| nvnc_log(NVNC_LOG_ERROR, "Password comparision failed"); | ||
| return false; | ||
| } | ||
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| static int on_vnc_auth_des_challenge_message(struct nvnc_client *client) | ||
| { | ||
| if (!client) | ||
| { | ||
| nvnc_log(NVNC_LOG_ERROR, "Client is NULL"); | ||
| return 0; | ||
| } | ||
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| if (!client->msg_buffer) | ||
| { | ||
| nvnc_log(NVNC_LOG_ERROR, "Message buffer is NULL"); | ||
| return 0; | ||
| } | ||
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| if (client->buffer_len < client->buffer_index + CHALLENGESIZE) | ||
| { | ||
| nvnc_log(NVNC_LOG_WARNING, "Buffer index out of bounds"); | ||
| return 0; | ||
| } | ||
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| nvnc_log(NVNC_LOG_DEBUG, "on_vnc_auth_des_challenge_message called"); | ||
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| uint8_t response[CHALLENGESIZE]; | ||
| memcpy(response, client->msg_buffer + client->buffer_index, CHALLENGESIZE); | ||
| response[CHALLENGESIZE] = '\0'; | ||
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| if (!compare_challenges(client, (const char *)response, CHALLENGESIZE)) | ||
| { | ||
| security_handshake_failed(client, "", "Invalid password"); | ||
| } | ||
| else | ||
| { | ||
| security_handshake_ok(client, ""); | ||
| client->state = VNC_CLIENT_STATE_WAITING_FOR_INIT; | ||
| } | ||
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| return CHALLENGESIZE; | ||
| } | ||
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| int vnc_auth_handle_message(struct nvnc_client *client) | ||
| { | ||
| nvnc_log(NVNC_LOG_DEBUG, "vnc_auth_handle_message called"); | ||
| if (!client) | ||
| return 0; | ||
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| switch (client->state) | ||
| { | ||
| case VNC_CLIENT_STATE_WAITING_FOR_CHALLENGE: | ||
| return on_vnc_auth_des_challenge_message(client); | ||
| default:; | ||
| } | ||
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| nvnc_log(NVNC_LOG_DEBUG, "Unhandled client state: %d", client->state); | ||
| return 0; | ||
| } |
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