sysadmin/ipxe
1
0
Fork 0
mirror of https://github.com/ipxe/ipxe synced 2026-02-01 07:26:44 +03:00
Code Issues Packages Projects Releases Wiki Activity

[crypto] Simplify internal HMAC API

Browse Source 
Simplify the internal HMAC API so that the key is provided only at the
point of calling hmac_init(), and the (potentially reduced) key is
stored as part of the context for later use by hmac_final().

This simplifies the calling code, and avoids the need for callers such
as TLS to allocate a potentially variable length block in order to
retain a copy of the unmodified key.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2022-10-09 15:14:41 +01:00
parent 88419b608d
commit 007d3cb800
16 changed files with 142 additions and 163 deletions
Download Patch File Download Diff File Expand all files Collapse all files

96
src/crypto/hmac.c
View File

@@ -46,94 +46,62 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <ipxe/crypto.h>
#include <ipxe/hmac.h>
/**
* Reduce HMAC key length
*
* @v digest Digest algorithm to use
* @v digest_ctx Digest context
* @v key Key
* @v key_len Length of key
*/
static void hmac_reduce_key ( struct digest_algorithm *digest,
void *key, size_t *key_len ) {
uint8_t digest_ctx[digest->ctxsize];
digest_init ( digest, digest_ctx );
digest_update ( digest, digest_ctx, key, *key_len );
digest_final ( digest, digest_ctx, key );
*key_len = digest->digestsize;
}
/**
* Initialise HMAC
*
* @v digest Digest algorithm to use
* @v digest_ctx Digest context
* @v ctx HMAC context
* @v key Key
* @v key_len Length of key
*
* The length of the key should be less than the block size of the
* digest algorithm being used. (If the key length is greater, it
* will be replaced with its own digest, and key_len will be updated
* accordingly).
*/
void hmac_init ( struct digest_algorithm *digest, void *digest_ctx,
void *key, size_t *key_len ) {
unsigned char k_ipad[digest->blocksize];
void hmac_init ( struct digest_algorithm *digest, void *ctx, const void *key,
size_t key_len ) {
hmac_context_t ( digest ) *hctx = ctx;
unsigned int i;
/* Reduce key if necessary */
if ( *key_len > sizeof ( k_ipad ) )
hmac_reduce_key ( digest, key, key_len );
/* Construct input pad */
memset ( k_ipad, 0, sizeof ( k_ipad ) );
memcpy ( k_ipad, key, *key_len );
for ( i = 0 ; i < sizeof ( k_ipad ) ; i++ ) {
k_ipad[i] ^= 0x36;
memset ( hctx->pad, 0, sizeof ( hctx->pad ) );
if ( key_len <= sizeof ( hctx->pad ) ) {
memcpy ( hctx->pad, key, key_len );
} else {
digest_init ( digest, hctx->ctx );
digest_update ( digest, hctx->ctx, key, key_len );
digest_final ( digest, hctx->ctx, hctx->pad );
}
for ( i = 0 ; i < sizeof ( hctx->pad ) ; i++ ) {
hctx->pad[i] ^= 0x36;
}
/* Start inner hash */
digest_init ( digest, digest_ctx );
digest_update ( digest, digest_ctx, k_ipad, sizeof ( k_ipad ) );
digest_init ( digest, hctx->ctx );
digest_update ( digest, hctx->ctx, hctx->pad, sizeof ( hctx->pad ) );
}
/**
* Finalise HMAC
*
* @v digest Digest algorithm to use
* @v digest_ctx Digest context
* @v key Key
* @v key_len Length of key
* @v ctx HMAC context
* @v hmac HMAC digest to fill in
*
* The length of the key should be less than the block size of the
* digest algorithm being used. (If the key length is greater, it
* will be replaced with its own digest, and key_len will be updated
* accordingly).
*/
void hmac_final ( struct digest_algorithm *digest, void *digest_ctx,
void *key, size_t *key_len, void *hmac ) {
unsigned char k_opad[digest->blocksize];
void hmac_final ( struct digest_algorithm *digest, void *ctx, void *hmac ) {
hmac_context_t ( digest ) *hctx = ctx;
unsigned int i;
/* Reduce key if necessary */
if ( *key_len > sizeof ( k_opad ) )
hmac_reduce_key ( digest, key, key_len );
/* Construct output pad */
memset ( k_opad, 0, sizeof ( k_opad ) );
memcpy ( k_opad, key, *key_len );
for ( i = 0 ; i < sizeof ( k_opad ) ; i++ ) {
k_opad[i] ^= 0x5c;
/* Construct output pad from input pad */
for ( i = 0 ; i < sizeof ( hctx->pad ) ; i++ ) {
hctx->pad[i] ^= 0x6a;
}
/* Finish inner hash */
digest_final ( digest, digest_ctx, hmac );
digest_final ( digest, hctx->ctx, hmac );
/* Perform outer hash */
digest_init ( digest, digest_ctx );
digest_update ( digest, digest_ctx, k_opad, sizeof ( k_opad ) );
digest_update ( digest, digest_ctx, hmac, digest->digestsize );
digest_final ( digest, digest_ctx, hmac );
digest_init ( digest, hctx->ctx );
digest_update ( digest, hctx->ctx, hctx->pad, sizeof ( hctx->pad ) );
digest_update ( digest, hctx->ctx, hmac, digest->digestsize );
digest_final ( digest, hctx->ctx, hmac );
/* Erase output pad (from which the key may be derivable) */
memset ( hctx->pad, 0, sizeof ( hctx->pad ) );
}

16
src/crypto/hmac_drbg.c
View File

@@ -79,7 +79,7 @@ static void hmac_drbg_update_key ( struct digest_algorithm *hash,
struct hmac_drbg_state *state,
const void *data, size_t len,
const uint8_t single ) {
uint8_t context[ hash->ctxsize ];
uint8_t context[ hmac_ctxsize ( hash ) ];
size_t out_len = hash->digestsize;
DBGC ( state, "HMAC_DRBG_%s %p provided data :\n", hash->name, state );
@@ -92,13 +92,11 @@ static void hmac_drbg_update_key ( struct digest_algorithm *hash,
assert ( ( single == 0x00 ) || ( single == 0x01 ) );
/* K = HMAC ( K, V || single || provided_data ) */
hmac_init ( hash, context, state->key, &out_len );
assert ( out_len == hash->digestsize );
hmac_init ( hash, context, state->key, out_len );
hmac_update ( hash, context, state->value, out_len );
hmac_update ( hash, context, &single, sizeof ( single ) );
hmac_update ( hash, context, data, len );
hmac_final ( hash, context, state->key, &out_len, state->key );
assert ( out_len == hash->digestsize );
hmac_final ( hash, context, state->key );
DBGC ( state, "HMAC_DRBG_%s %p K = HMAC ( K, V || %#02x || "
"provided_data ) :\n", hash->name, state, single );
@@ -122,7 +120,7 @@ static void hmac_drbg_update_key ( struct digest_algorithm *hash,
*/
static void hmac_drbg_update_value ( struct digest_algorithm *hash,
struct hmac_drbg_state *state ) {
uint8_t context[ hash->ctxsize ];
uint8_t context[ hmac_ctxsize ( hash ) ];
size_t out_len = hash->digestsize;
/* Sanity checks */
@@ -130,11 +128,9 @@ static void hmac_drbg_update_value ( struct digest_algorithm *hash,
assert ( state != NULL );
/* V = HMAC ( K, V ) */
hmac_init ( hash, context, state->key, &out_len );
assert ( out_len == hash->digestsize );
hmac_init ( hash, context, state->key, out_len );
hmac_update ( hash, context, state->value, out_len );
hmac_final ( hash, context, state->key, &out_len, state->value );
assert ( out_len == hash->digestsize );
hmac_final ( hash, context, state->value );
DBGC ( state, "HMAC_DRBG_%s %p V = HMAC ( K, V ) :\n",
hash->name, state );

19
src/crypto/ntlm.c
View File

@@ -117,10 +117,9 @@ void ntlm_key ( const char *domain, const char *username,
struct digest_algorithm *md5 = &md5_algorithm;
union {
uint8_t md4[MD4_CTX_SIZE];
uint8_t md5[MD5_CTX_SIZE];
uint8_t md5[ MD5_CTX_SIZE + MD5_BLOCK_SIZE ];
} ctx;
uint8_t digest[MD4_DIGEST_SIZE];
size_t digest_len;
uint8_t c;
uint16_t wc;
@@ -141,8 +140,7 @@ void ntlm_key ( const char *domain, const char *username,
digest_final ( md4, ctx.md4, digest );
/* Construct HMAC-MD5 of (Unicode) upper-case username */
digest_len = sizeof ( digest );
hmac_init ( md5, ctx.md5, digest, &digest_len );
hmac_init ( md5, ctx.md5, digest, sizeof ( digest ) );
while ( ( c = *(username++) ) ) {
wc = cpu_to_le16 ( toupper ( c ) );
hmac_update ( md5, ctx.md5, &wc, sizeof ( wc ) );
@@ -151,7 +149,7 @@ void ntlm_key ( const char *domain, const char *username,
wc = cpu_to_le16 ( c );
hmac_update ( md5, ctx.md5, &wc, sizeof ( wc ) );
}
hmac_final ( md5, ctx.md5, digest, &digest_len, key->raw );
hmac_final ( md5, ctx.md5, key->raw );
DBGC ( key, "NTLM key:\n" );
DBGC_HDA ( key, 0, key, sizeof ( *key ) );
}
@@ -170,8 +168,7 @@ void ntlm_response ( struct ntlm_challenge_info *info, struct ntlm_key *key,
struct ntlm_nt_response *nt ) {
struct digest_algorithm *md5 = &md5_algorithm;
struct ntlm_nonce tmp_nonce;
uint8_t ctx[MD5_CTX_SIZE];
size_t key_len = sizeof ( *key );
uint8_t ctx[ MD5_CTX_SIZE + MD5_BLOCK_SIZE ];
unsigned int i;
/* Generate random nonce, if needed */
@@ -183,10 +180,10 @@ void ntlm_response ( struct ntlm_challenge_info *info, struct ntlm_key *key,
/* Construct LAN Manager response */
memcpy ( &lm->nonce, nonce, sizeof ( lm->nonce ) );
hmac_init ( md5, ctx, key->raw, &key_len );
hmac_init ( md5, ctx, key->raw, sizeof ( *key ) );
hmac_update ( md5, ctx, info->nonce, sizeof ( *info->nonce ) );
hmac_update ( md5, ctx, &lm->nonce, sizeof ( lm->nonce ) );
hmac_final ( md5, ctx, key->raw, &key_len, lm->digest );
hmac_final ( md5, ctx, lm->digest );
DBGC ( key, "NTLM LAN Manager response:\n" );
DBGC_HDA ( key, 0, lm, sizeof ( *lm ) );
@@ -195,14 +192,14 @@ void ntlm_response ( struct ntlm_challenge_info *info, struct ntlm_key *key,
nt->version = NTLM_VERSION_NTLMV2;
nt->high = NTLM_VERSION_NTLMV2;
memcpy ( &nt->nonce, nonce, sizeof ( nt->nonce ) );
hmac_init ( md5, ctx, key->raw, &key_len );
hmac_init ( md5, ctx, key->raw, sizeof ( *key ) );
hmac_update ( md5, ctx, info->nonce, sizeof ( *info->nonce ) );
hmac_update ( md5, ctx, &nt->version,
( sizeof ( *nt ) -
offsetof ( typeof ( *nt ), version ) ) );
hmac_update ( md5, ctx, info->target, info->len );
hmac_update ( md5, ctx, &nt->zero, sizeof ( nt->zero ) );
hmac_final ( md5, ctx, key->raw, &key_len, nt->digest );
hmac_final ( md5, ctx, nt->digest );
DBGC ( key, "NTLM NT response prefix:\n" );
DBGC_HDA ( key, 0, nt, sizeof ( *nt ) );
}

16
src/crypto/sha1extra.c
View File

@@ -49,7 +49,7 @@ void prf_sha1 ( const void *key, size_t key_len, const char *label,
u8 in[strlen ( label ) + 1 + data_len + 1]; /* message to HMAC */
u8 *in_blknr; /* pointer to last byte of in, block number */
u8 out[SHA1_DIGEST_SIZE]; /* HMAC-SHA1 result */
u8 sha1_ctx[SHA1_CTX_SIZE]; /* SHA1 context */
u8 ctx[SHA1_CTX_SIZE + SHA1_BLOCK_SIZE]; /* HMAC-SHA1 context */
const size_t label_len = strlen ( label );
/* The HMAC-SHA-1 is calculated using the given key on the
@@ -65,9 +65,9 @@ void prf_sha1 ( const void *key, size_t key_len, const char *label,
for ( blk = 0 ;; blk++ ) {
*in_blknr = blk;
hmac_init ( &sha1_algorithm, sha1_ctx, keym, &key_len );
hmac_update ( &sha1_algorithm, sha1_ctx, in, sizeof ( in ) );
hmac_final ( &sha1_algorithm, sha1_ctx, keym, &key_len, out );
hmac_init ( &sha1_algorithm, ctx, keym, key_len );
hmac_update ( &sha1_algorithm, ctx, in, sizeof ( in ) );
hmac_final ( &sha1_algorithm, ctx, out );
if ( prf_len <= sizeof ( out ) ) {
memcpy ( prf, out, prf_len );
@@ -100,7 +100,7 @@ static void pbkdf2_sha1_f ( const void *passphrase, size_t pass_len,
u8 pass[pass_len]; /* modifiable passphrase */
u8 in[salt_len + 4]; /* input buffer to first round */
u8 last[SHA1_DIGEST_SIZE]; /* output of round N, input of N+1 */
u8 sha1_ctx[SHA1_CTX_SIZE];
u8 ctx[SHA1_CTX_SIZE + SHA1_BLOCK_SIZE];
u8 *next_in = in; /* changed to `last' after first round */
int next_size = sizeof ( in );
int i;
@@ -114,9 +114,9 @@ static void pbkdf2_sha1_f ( const void *passphrase, size_t pass_len,
memset ( block, 0, sizeof ( last ) );
for ( i = 0; i < iterations; i++ ) {
hmac_init ( &sha1_algorithm, sha1_ctx, pass, &pass_len );
hmac_update ( &sha1_algorithm, sha1_ctx, next_in, next_size );
hmac_final ( &sha1_algorithm, sha1_ctx, pass, &pass_len, last );
hmac_init ( &sha1_algorithm, ctx, pass, pass_len );
hmac_update ( &sha1_algorithm, ctx, next_in, next_size );
hmac_final ( &sha1_algorithm, ctx, last );
for ( j = 0; j < sizeof ( last ); j++ ) {
block[j] ^= last[j];