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Move PKCS#12 key derivation to a separate file

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This commit is contained in:
Tobias Brunner
2013-05-08 15:02:39 +02:00
parent 594d847f79
commit d41e54c68d
5 changed files with 238 additions and 147 deletions
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src/libstrongswan/crypto/pkcs5.c
+11 -145
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@@ -19,6 +19,7 @@
#include <asn1/oid.h>
#include <asn1/asn1.h>
#include <asn1/asn1_parser.h>
#include <credentials/containers/pkcs12.h>
typedef struct private_pkcs5_t private_pkcs5_t;
@@ -161,156 +162,19 @@ static bool decrypt_generic(private_pkcs5_t *this, chunk_t password,
}
/**
* v * ceiling(len/v)
*/
#define PKCS12_LEN(len, v) (((len) + v-1) & ~(v-1))
/**
* Copy src to dst as many times as possible
*/
static inline void pkcs12_copy_chunk(chunk_t dst, chunk_t src)
{
size_t i;
for (i = 0; i < dst.len; i++)
{
dst.ptr[i] = src.ptr[i % src.len];
}
}
/**
* Treat two chunks as integers in network order and add them together.
* The result is stored in the first chunk, if the second chunk is longer or the
* result overflows this is ignored.
*/
static void pkcs12_add_chunks(chunk_t a, chunk_t b)
{
u_int16_t sum;
u_int8_t rem = 0;
ssize_t i, j;
for (i = a.len - 1, j = b.len -1; i >= 0 && j >= 0; i--, j--)
{
sum = a.ptr[i] + b.ptr[j] + rem;
a.ptr[i] = (u_char)sum;
rem = sum >> 8;
}
for (; i >= 0 && rem; i--)
{
sum = a.ptr[i] + rem;
a.ptr[i] = (u_char)sum;
rem = sum >> 8;
}
}
/**
* Do the actual key derivation with the given password and id
* id is 1 for encryption keys, 2 for IVs, 3 for MAC keys.
*/
static bool pkcs12_derive(private_pkcs5_t *this, chunk_t unicode,
char id, chunk_t result)
{
chunk_t out = result, D, S, P = chunk_empty, I, Ai, B, Ij;
hasher_t *hasher;
size_t Slen, v, u;
u_int64_t i;
switch (this->data.pbes1.hash)
{
case HASH_MD2:
case HASH_MD5:
case HASH_SHA1:
case HASH_SHA224:
case HASH_SHA256:
v = 64;
break;
case HASH_SHA384:
case HASH_SHA512:
v = 128;
break;
default:
return FALSE;
}
hasher = this->data.pbes1.hasher;
u = hasher->get_hash_size(hasher);
D = chunk_alloca(v);
memset(D.ptr, id, D.len);
Slen = PKCS12_LEN(this->salt.len, v);
I = chunk_alloca(Slen + PKCS12_LEN(unicode.len, v));
S = chunk_create(I.ptr, Slen);
P = chunk_create(I.ptr + Slen, I.len - Slen);
pkcs12_copy_chunk(S, this->salt);
pkcs12_copy_chunk(P, unicode);
Ai = chunk_alloca(u);
B = chunk_alloca(v);
while (TRUE)
{
if (!hasher->get_hash(hasher, D, NULL) ||
!hasher->get_hash(hasher, I, Ai.ptr))
{
return FALSE;
}
for (i = 1; i < this->iterations; i++)
{
if (!hasher->get_hash(hasher, Ai, Ai.ptr))
{
return FALSE;
}
}
memcpy(out.ptr, Ai.ptr, min(out.len, Ai.len));
out = chunk_skip(out, Ai.len);
if (!out.len)
{
break;
}
pkcs12_copy_chunk(B, Ai);
/* B = B+1 */
pkcs12_add_chunks(B, chunk_from_chars(0x01));
Ij = chunk_create(I.ptr, v);
while (Ij.len)
{ /* Ij = Ij + B + 1 */
pkcs12_add_chunks(Ij, B);
Ij = chunk_skip(Ij, v);
}
}
return TRUE;
}
/**
* KDF defined in PKCS#12
* KDF as used by PKCS#12
*/
static bool pkcs12_kdf(private_pkcs5_t *this, chunk_t password, chunk_t keymat)
{
chunk_t unicode = chunk_empty, key, iv;
int i;
if (password.len)
{ /* convert the password to UTF-16BE (without BOM) with 0 terminator */
unicode = chunk_alloca(password.len * 2 + 2);
for (i = 0; i < password.len; i++)
{
unicode.ptr[i * 2] = 0;
unicode.ptr[i * 2 + 1] = password.ptr[i];
}
unicode.ptr[i * 2] = 0;
unicode.ptr[i * 2 + 1] = 0;
}
chunk_t key, iv;
key = chunk_create(keymat.ptr, this->keylen);
iv = chunk_create(keymat.ptr + this->keylen, keymat.len - this->keylen);
if (!pkcs12_derive(this, unicode, 1, key) ||
!pkcs12_derive(this, unicode, 2, iv))
{
memwipe(unicode.ptr, unicode.len);
return FALSE;
}
memwipe(unicode.ptr, unicode.len);
return TRUE;
return pkcs12_derive_key(this->data.pbes1.hash, password, this->salt,
this->iterations, PKCS12_KEY_ENCRYPTION, key) &&
pkcs12_derive_key(this->data.pbes1.hash, password, this->salt,
this->iterations, PKCS12_KEY_IV, iv);
}
/**
@@ -426,7 +290,6 @@ static bool ensure_crypto_primitives(private_pkcs5_t *this, chunk_t data)
switch (this->scheme)
{
case PKCS5_SCHEME_PBES1:
case PKCS5_SCHEME_PKCS12:
{
if (!this->data.pbes1.hasher)
{
@@ -466,6 +329,8 @@ static bool ensure_crypto_primitives(private_pkcs5_t *this, chunk_t data)
this->data.pbes2.prf = prf;
}
}
case PKCS5_SCHEME_PKCS12:
break;
}
return TRUE;
}
@@ -699,13 +564,14 @@ METHOD(pkcs5_t, destroy, void,
switch (this->scheme)
{
case PKCS5_SCHEME_PBES1:
case PKCS5_SCHEME_PKCS12:
DESTROY_IF(this->data.pbes1.hasher);
break;
case PKCS5_SCHEME_PBES2:
DESTROY_IF(this->data.pbes2.prf);
chunk_free(&this->data.pbes2.iv);
break;
case PKCS5_SCHEME_PKCS12:
break;
}
free(this);
}