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wolfssh
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Code Issues Releases Wiki Activity

Added packet encryption and adding MAC

pull/1/head
John Safranek 2014-12-16 13:17:18 -08:00
parent 2ae2d6dcdf
commit 6c49caf9ab
3 changed files with 109 additions and 54 deletions
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154
src/internal.c
View File

@ -127,7 +127,13 @@ const char* GetErrorString(int err)
case WS_DECRYPT_E:
return "decrypt error";
case WS_MAC_E:
case WS_ENCRYPT_E:
return "encrypt error";
case WS_VERIFY_MAC_E:
return "verify mac error";
case WS_CREATE_MAC_E:
return "verify mac error";
default:
@ -1218,6 +1224,33 @@ static int DoPacket(WOLFSSH* ssh)
}
static INLINE int Encrypt(WOLFSSH* ssh, uint8_t* cipher, const uint8_t* input,
uint16_t sz)
{
int ret = WS_SUCCESS;
if (ssh == NULL || cipher == NULL || input == NULL || sz == 0)
return WS_BAD_ARGUMENT;
WLOG(WS_LOG_DEBUG, "Encrypt %s", IdToName(ssh->encryptId));
switch (ssh->encryptId) {
case ID_NONE:
break;
case ID_AES128_CBC:
if (AesCbcEncrypt(&ssh->encryptCipher.aes, cipher, input, sz) < 0)
ret = WS_ENCRYPT_E;
break;
default:
ret = WS_INVALID_ALGO_ID;
}
return ret;
}
static INLINE int Decrypt(WOLFSSH* ssh, uint8_t* plain, const uint8_t* input,
uint16_t sz)
{
@ -1245,6 +1278,51 @@ static INLINE int Decrypt(WOLFSSH* ssh, uint8_t* plain, const uint8_t* input,
}
static INLINE int CreateMac(WOLFSSH* ssh, const uint8_t* in, uint32_t inSz,
uint8_t* mac)
{
uint8_t flatSeq[LENGTH_SZ];
c32toa(ssh->seq++, flatSeq);
/* Need to MAC the sequence number and the unencrypted packet */
switch (ssh->macId) {
case ID_NONE:
break;
case ID_HMAC_SHA1_96:
{
Hmac hmac;
uint8_t digest[SHA_DIGEST_SIZE];
HmacSetKey(&hmac, SHA, ssh->macKeyServer, ssh->macKeyServerSz);
HmacUpdate(&hmac, flatSeq, sizeof(flatSeq));
HmacUpdate(&hmac, in, inSz);
HmacFinal(&hmac, digest);
WMEMCPY(mac, digest, SHA1_96_SZ);
}
break;
case ID_HMAC_SHA1:
{
Hmac hmac;
HmacSetKey(&hmac, SHA, ssh->macKeyServer, ssh->macKeyServerSz);
HmacUpdate(&hmac, flatSeq, sizeof(flatSeq));
HmacUpdate(&hmac, in, inSz);
HmacFinal(&hmac, mac);
}
break;
default:
WLOG(WS_LOG_DEBUG, "Invalid Mac ID");
return WS_FATAL_ERROR;
}
return WS_SUCCESS;
}
static INLINE int VerifyMac(WOLFSSH* ssh, const uint8_t* in, uint32_t inSz,
const uint8_t* mac)
{
@ -1270,10 +1348,8 @@ static INLINE int VerifyMac(WOLFSSH* ssh, const uint8_t* in, uint32_t inSz,
HmacUpdate(&hmac, flatSeq, sizeof(flatSeq));
HmacUpdate(&hmac, in, inSz);
HmacFinal(&hmac, checkMac);
DumpOctetString(mac, ssh->peerMacSz);
DumpOctetString(checkMac, ssh->peerMacSz);
if (WMEMCMP(checkMac, mac, ssh->peerMacSz) != 0)
ret = WS_MAC_E;
ret = WS_VERIFY_MAC_E;
break;
default:
@ -1418,7 +1494,8 @@ static int PreparePacket(WOLFSSH* ssh, uint32_t payloadSz)
uint8_t paddingSz;
/* Minimum value for paddingSz is 4. */
paddingSz = ssh->blockSz - (LENGTH_SZ + PAD_LENGTH_SZ + payloadSz) % ssh->blockSz;
paddingSz = ssh->blockSz -
(LENGTH_SZ + PAD_LENGTH_SZ + payloadSz) % ssh->blockSz;
if (paddingSz < 4)
paddingSz += ssh->blockSz;
ssh->paddingSz = paddingSz;
@ -1428,6 +1505,7 @@ static int PreparePacket(WOLFSSH* ssh, uint32_t payloadSz)
if ( (ret = GrowBuffer(&ssh->outputBuffer, outputSz, 0)) != WS_SUCCESS)
return ret;
ssh->packetStartIdx = ssh->outputBuffer.length;
output = ssh->outputBuffer.buffer + ssh->outputBuffer.length;
/* fill in the packetSz, paddingSz */
@ -1445,63 +1523,37 @@ static int BundlePacket(WOLFSSH* ssh)
uint8_t* output;
uint32_t idx;
uint8_t paddingSz;
uint8_t flatSeq[LENGTH_SZ];
output = ssh->outputBuffer.buffer;
idx = ssh->outputBuffer.length;
paddingSz = ssh->paddingSz;
c32toa(ssh->seq++, flatSeq);
/* Add the padding */
WMEMSET(output + idx, 0, paddingSz);
if (ssh->encryptId == ID_NONE)
WMEMSET(output + idx, 0, paddingSz);
else
RNG_GenerateBlock(ssh->rng, output + idx, paddingSz);
idx += paddingSz;
/* Need to MAC the sequence number and the unencrypted packet */
switch (ssh->macId) {
case ID_NONE:
break;
#if 0
case ID_HMAC_SHA1_96:
{
Hmac hmac;
uint8_t digest[SHA_DIGEST_SIZE];
CreateMac(ssh, ssh->outputBuffer.buffer + ssh->packetStartIdx,
ssh->outputBuffer.length - ssh->packetStartIdx + paddingSz,
output + idx);
idx += ssh->macSz;
HmacSetKey(&hmac, SHA, ssh->macKeyServer, ssh->macKeyServerSz);
HmacUpdate(&hmac, flatSeq, sizeof(flatSeq));
HmacUpdate(&hmac,);
HmacFinal(&hmac, digest);
WMEMCPY(, digest, SHA1_96_SIZE);
}
break;
WLOG(WS_LOG_DEBUG, "packetStartIdx = %u", ssh->packetStartIdx);
WLOG(WS_LOG_DEBUG, "length = %u", ssh->outputBuffer.length);
WLOG(WS_LOG_DEBUG, "Before encrypt:");
DumpOctetString(ssh->outputBuffer.buffer + ssh->packetStartIdx,
ssh->outputBuffer.length - ssh->packetStartIdx + paddingSz);
case ID_HMAC_SHA1:
{
Hmac hmac;
Encrypt(ssh,
ssh->outputBuffer.buffer + ssh->packetStartIdx,
ssh->outputBuffer.buffer + ssh->packetStartIdx,
ssh->outputBuffer.length - ssh->packetStartIdx + paddingSz);
HmacSetKey(&hmac, SHA, ssh->macKeyServer, ssh->macKeyServerSz);
HmacUpdate(&hmac, flatSeq, sizeof(flatSeq));
HmacUpdate(&hmac,);
HmacFinal(&hmac, );
}
break;
#endif
default:
WLOG(WS_LOG_DEBUG, "Invalid Mac ID");
return WS_FATAL_ERROR;
}
/* Encrypt the packet */
switch (ssh->encryptId) {
case ID_NONE:
break;
#if 0
case ID_AES128_CBC:
break;
#endif
default:
WLOG(WS_LOG_DEBUG, "Invalid Encrypt ID");
return WS_FATAL_ERROR;
}
WLOG(WS_LOG_DEBUG, "After encrypt:");
DumpOctetString(ssh->outputBuffer.buffer + ssh->packetStartIdx,
ssh->outputBuffer.length - ssh->packetStartIdx + paddingSz);
ssh->outputBuffer.length = idx;

4
wolfssh/error.h
View File

@ -61,7 +61,9 @@ enum WS_ErrorCodes {
WS_BAD_FILE_E = -19,
WS_INVALID_ALGO_ID = -20,
WS_DECRYPT_E = -21,
WS_MAC_E = -22
WS_ENCRYPT_E = -22,
WS_VERIFY_MAC_E = -23,
WS_CREATE_MAC_E = -24
};

5
wolfssh/internal.h
View File

@ -100,7 +100,7 @@ WOLFSSH_LOCAL uint8_t NameToId(const char*, uint32_t);
WOLFSSH_LOCAL const char* IdToName(uint8_t);
#define STATIC_BUFFER_LEN 16
#define STATIC_BUFFER_LEN AES_BLOCK_SIZE
/* This is one AES block size. We always grab one
* block size first to decrypt to find the size of
* the rest of the data. */
@ -171,7 +171,8 @@ struct WOLFSSH {
uint32_t curSz;
uint32_t seq;
uint32_t peerSeq;
uint8_t paddingSz;
uint32_t packetStartIdx; /* Current send packet start index */
uint8_t paddingSz; /* Current send packet padding size */
uint8_t acceptState;
uint8_t clientState;
uint8_t processReplyState;