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Proto_IkePacket.c: fix and improve IkeHMac() function

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Pull request #294 added SHA-256, SHA-384, and SHA-512 support to the protocol, but part of it was removed in faee11ff09, because it caused a buffer over-read crash.

It also broke the MD5 implementation because the switch-case block didn't handle the type anymore.

This pull request fixes all the implementations and improves the IkeHMac() function by using the dedicated hashing functions.
This commit is contained in:
Davide Beatrici 2018-09-11 15:29:12 +02:00
parent 8fdd224ba7
commit 32082eb8af
1 changed files with 24 additions and 88 deletions
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112
src/Cedar/Proto_IkePacket.c
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@ -2963,108 +2963,44 @@ void IkeHash(IKE_HASH *h, void *dst, void *src, UINT size)
// Calculation of HMAC // Calculation of HMAC
void IkeHMac(IKE_HASH *h, void *dst, void *key, UINT key_size, void *data, UINT data_size) void IkeHMac(IKE_HASH *h, void *dst, void *key, UINT key_size, void *data, UINT data_size)
{ {
UINT hmac_block_size = HMAC_BLOCK_SIZE; MD *md = NULL;
UCHAR k[HMAC_BLOCK_SIZE_MAX];
UCHAR *data1;
UCHAR hash1[IKE_MAX_HASH_SIZE];
UINT data1_size;
UCHAR data2[IKE_MAX_HASH_SIZE + HMAC_BLOCK_SIZE_MAX];
UINT data2_size;
UCHAR tmp1600[1600];
bool no_free = false;
UINT i;
// Validate arguments // Validate arguments
if (h == NULL || dst == NULL || (key == NULL && key_size != 0) || (data == NULL && data_size != 0)) if (h == NULL || dst == NULL || (key == NULL && key_size != 0) || (data == NULL && data_size != 0))
{ {
return; return;
} }
switch (h->HashId) switch(h->HashId)
{ {
case IKE_HASH_SHA1_ID: case IKE_HASH_MD5_ID:
case IKE_HASH_SHA2_256_ID: md = NewMd("MD5");
hmac_block_size = HMAC_BLOCK_SIZE; break;
break; case IKE_HASH_SHA1_ID:
md = NewMd("SHA1");
case IKE_HASH_SHA2_384_ID: break;
case IKE_HASH_SHA2_512_ID: case IKE_HASH_SHA2_256_ID:
hmac_block_size = HMAC_BLOCK_SIZE_1024; md = NewMd("SHA256");
break; break;
case IKE_HASH_SHA2_384_ID:
default: md = NewMd("SHA384");
return; break;
case IKE_HASH_SHA2_512_ID:
md = NewMd("SHA512");
break;
} }
if (hmac_block_size > HMAC_BLOCK_SIZE_MAX) if (md == NULL)
{ {
Debug("IkeHMac(): The MD object is NULL! Either NewMd() failed or the current algorithm is not handled by the switch-case block.");
return; return;
} }
if (h->HashId == IKE_HASH_SHA1_ID) SetMdKey(md, key, key_size);
{ MdProcess(md, dst, data, data_size);
// Use special function (fast) in the case of SHA-1 FreeMd(md);
HMacSha1(dst, key, key_size, data, data_size);
return;
}
else if (h->HashId == IKE_HASH_MD5_ID)
{
// Use the special function (fast) in the case of MD5
HMacMd5(dst, key, key_size, data, data_size);
return;
}
// Creating a K
Zero(k, sizeof(k));
if (key_size <= hmac_block_size)
{
Copy(k, key, key_size);
}
else
{
IkeHash(h, k, key, key_size);
}
// Generation of data 1
data1_size = data_size + hmac_block_size;
if (data1_size > sizeof(tmp1600))
{
data1 = Malloc(data1_size);
}
else
{
data1 = tmp1600;
no_free = true;
}
for (i = 0;i < hmac_block_size;i++)
{
data1[i] = k[i] ^ 0x36;
}
Copy(data1 + hmac_block_size, data, data_size);
// Calculate the hash value
IkeHash(h, hash1, data1, data1_size);
if (no_free == false)
{
Free(data1);
}
// Generation of data 2
data2_size = h->HashSize + hmac_block_size;
for (i = 0;i < hmac_block_size;i++)
{
data2[i] = k[i] ^ 0x5c;
}
Copy(data2 + hmac_block_size, hash1, h->HashSize);
// Calculate the hash value
IkeHash(h, dst, data2, data2_size);
} }
void IkeHMacBuf(IKE_HASH *h, void *dst, BUF *key, BUF *data) void IkeHMacBuf(IKE_HASH *h, void *dst, BUF *key, BUF *data)
{ {
// Validate arguments // Validate arguments