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SSH2 MACs now use dynamically allocated contexts.

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[originally from svn r2131]
This commit is contained in:
Simon Tatham 2002-10-25 12:51:28 +00:00
parent 9848062b86
commit 8f91f07599
4 changed files with 108 additions and 85 deletions
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39
ssh.c
View File

@ -371,19 +371,28 @@ const static struct ssh_kex *kex_algs[] = {
const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
static void nullmac_key(unsigned char *key)
static void *nullmac_make_context(void)
{
return NULL;
}
static void nullmac_free_context(void *handle)
{
}
static void nullmac_generate(unsigned char *blk, int len,
static void nullmac_key(void *handle, unsigned char *key)
{
}
static void nullmac_generate(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
}
static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
static int nullmac_verify(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
return 1;
}
const static struct ssh_mac ssh_mac_none = {
nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
nullmac_make_context, nullmac_free_context, nullmac_key,
nullmac_generate, nullmac_verify, "none", 0
};
const static struct ssh_mac *macs[] = {
&ssh_sha1, &ssh_md5, &ssh_mac_none
@ -554,6 +563,7 @@ struct ssh_tag {
const struct ssh2_cipher *cscipher, *sccipher;
void *cs_cipher_ctx, *sc_cipher_ctx;
const struct ssh_mac *csmac, *scmac;
void *cs_mac_ctx, *sc_mac_ctx;
const struct ssh_compress *cscomp, *sccomp;
const struct ssh_kex *kex;
const struct ssh_signkey *hostkey;
@ -979,7 +989,7 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
* Check the MAC.
*/
if (ssh->scmac
&& !ssh->scmac->verify(ssh->pktin.data, st->len + 4,
&& !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
st->incoming_sequence)) {
bombout(("Incorrect MAC received on packet"));
crReturn(0);
@ -1468,7 +1478,8 @@ static int ssh2_pkt_construct(Ssh ssh)
ssh->pktout.data[ssh->pktout.length + i] = random_byte();
PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
if (ssh->csmac)
ssh->csmac->generate(ssh->pktout.data, ssh->pktout.length + padding,
ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
ssh->pktout.length + padding,
ssh->v2_outgoing_sequence);
ssh->v2_outgoing_sequence++; /* whether or not we MACed */
@ -4031,12 +4042,22 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
ssh->cscipher->free_context(ssh->cs_cipher_ctx);
ssh->cscipher = s->cscipher_tobe;
ssh->cs_cipher_ctx = ssh->cscipher->make_context();
if (ssh->sc_cipher_ctx)
ssh->sccipher->free_context(ssh->sc_cipher_ctx);
ssh->sccipher = s->sccipher_tobe;
ssh->sc_cipher_ctx = ssh->sccipher->make_context();
if (ssh->cs_mac_ctx)
ssh->csmac->free_context(ssh->cs_mac_ctx);
ssh->csmac = s->csmac_tobe;
ssh->cs_mac_ctx = ssh->csmac->make_context();
if (ssh->sc_mac_ctx)
ssh->scmac->free_context(ssh->sc_mac_ctx);
ssh->scmac = s->scmac_tobe;
ssh->sc_mac_ctx = ssh->scmac->make_context();
ssh->cscomp = s->cscomp_tobe;
ssh->sccomp = s->sccomp_tobe;
ssh->cscomp->compress_init();
@ -4059,9 +4080,9 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
ssh->csmac->setcskey(keyspace);
ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
ssh->scmac->setsckey(keyspace);
ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
}
{
char buf[256];
@ -5785,7 +5806,9 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
ssh->sccipher = NULL;
ssh->sc_cipher_ctx = NULL;
ssh->csmac = NULL;
ssh->sc_mac_ctx = NULL;
ssh->scmac = NULL;
ssh->sc_mac_ctx = NULL;
ssh->cscomp = NULL;
ssh->sccomp = NULL;
ssh->kex = NULL;

9
ssh.h
View File

@ -151,10 +151,11 @@ struct ssh2_ciphers {
};
struct ssh_mac {
void (*setcskey) (unsigned char *key);
void (*setsckey) (unsigned char *key);
void (*generate) (unsigned char *blk, int len, unsigned long seq);
int (*verify) (unsigned char *blk, int len, unsigned long seq);
void *(*make_context)(void);
void (*free_context)(void *);
void (*setkey) (void *, unsigned char *key);
void (*generate) (void *, unsigned char *blk, int len, unsigned long seq);
int (*verify) (void *, unsigned char *blk, int len, unsigned long seq);
char *name;
int len;
};

59
sshmd5.c
View File

@ -208,44 +208,46 @@ void MD5Final(unsigned char output[16], struct MD5Context *s)
* HMAC wrapper on it.
*/
static struct MD5Context md5_cs_mac_s1, md5_cs_mac_s2;
static struct MD5Context md5_sc_mac_s1, md5_sc_mac_s2;
static void md5_key(struct MD5Context *s1, struct MD5Context *s2,
unsigned char *key, int len)
static void *md5_make_context(void)
{
return smalloc(2*sizeof(struct MD5Context));
}
static void md5_free_context(void *handle)
{
sfree(handle);
}
static void md5_key_internal(void *handle, unsigned char *key, int len)
{
struct MD5Context *keys = (struct MD5Context *)handle;
unsigned char foo[64];
int i;
memset(foo, 0x36, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
MD5Init(s1);
MD5Update(s1, foo, 64);
MD5Init(&keys[0]);
MD5Update(&keys[0], foo, 64);
memset(foo, 0x5C, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
MD5Init(s2);
MD5Update(s2, foo, 64);
MD5Init(&keys[0]);
MD5Update(&keys[0], foo, 64);
memset(foo, 0, 64); /* burn the evidence */
}
static void md5_cskey(unsigned char *key)
static void md5_key(void *handle, unsigned char *key)
{
md5_key(&md5_cs_mac_s1, &md5_cs_mac_s2, key, 16);
md5_key_internal(handle, key, 16);
}
static void md5_sckey(unsigned char *key)
{
md5_key(&md5_sc_mac_s1, &md5_sc_mac_s2, key, 16);
}
static void md5_do_hmac(struct MD5Context *s1, struct MD5Context *s2,
unsigned char *blk, int len, unsigned long seq,
unsigned char *hmac)
static void md5_do_hmac(void *handle, unsigned char *blk, int len,
unsigned long seq, unsigned char *hmac)
{
struct MD5Context *keys = (struct MD5Context *)handle;
struct MD5Context s;
unsigned char intermediate[16];
@ -254,31 +256,32 @@ static void md5_do_hmac(struct MD5Context *s1, struct MD5Context *s2,
intermediate[2] = (unsigned char) ((seq >> 8) & 0xFF);
intermediate[3] = (unsigned char) ((seq) & 0xFF);
s = *s1; /* structure copy */
s = keys[0]; /* structure copy */
MD5Update(&s, intermediate, 4);
MD5Update(&s, blk, len);
MD5Final(intermediate, &s);
s = *s2; /* structure copy */
s = keys[1]; /* structure copy */
MD5Update(&s, intermediate, 16);
MD5Final(hmac, &s);
}
static void md5_generate(unsigned char *blk, int len, unsigned long seq)
static void md5_generate(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
md5_do_hmac(&md5_cs_mac_s1, &md5_cs_mac_s2, blk, len, seq, blk + len);
md5_do_hmac(handle, blk, len, seq, blk + len);
}
static int md5_verify(unsigned char *blk, int len, unsigned long seq)
static int md5_verify(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
unsigned char correct[16];
md5_do_hmac(&md5_sc_mac_s1, &md5_sc_mac_s2, blk, len, seq, correct);
md5_do_hmac(handle, blk, len, seq, correct);
return !memcmp(correct, blk + len, 16);
}
const struct ssh_mac ssh_md5 = {
md5_cskey, md5_sckey,
md5_generate,
md5_verify,
md5_make_context, md5_free_context, md5_key,
md5_generate, md5_verify,
"hmac-md5",
16
};

86
sshsha.c
View File

@ -193,54 +193,51 @@ void SHA_Simple(void *p, int len, unsigned char *output)
* HMAC wrapper on it.
*/
static SHA_State sha1_cs_mac_s1, sha1_cs_mac_s2;
static SHA_State sha1_sc_mac_s1, sha1_sc_mac_s2;
static void sha1_key(SHA_State * s1, SHA_State * s2,
unsigned char *key, int len)
static void *sha1_make_context(void)
{
return smalloc(2*sizeof(SHA_State));
}
static void sha1_free_context(void *handle)
{
sfree(handle);
}
static void sha1_key_internal(void *handle, unsigned char *key, int len)
{
SHA_State *keys = (SHA_State *)handle;
unsigned char foo[64];
int i;
memset(foo, 0x36, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
SHA_Init(s1);
SHA_Bytes(s1, foo, 64);
SHA_Init(&keys[0]);
SHA_Bytes(&keys[0], foo, 64);
memset(foo, 0x5C, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
SHA_Init(s2);
SHA_Bytes(s2, foo, 64);
SHA_Init(&keys[1]);
SHA_Bytes(&keys[1], foo, 64);
memset(foo, 0, 64); /* burn the evidence */
}
static void sha1_cskey(unsigned char *key)
static void sha1_key(void *handle, unsigned char *key)
{
sha1_key(&sha1_cs_mac_s1, &sha1_cs_mac_s2, key, 20);
sha1_key_internal(handle, key, 20);
}
static void sha1_sckey(unsigned char *key)
static void sha1_key_buggy(void *handle, unsigned char *key)
{
sha1_key(&sha1_sc_mac_s1, &sha1_sc_mac_s2, key, 20);
sha1_key_internal(handle, key, 16);
}
static void sha1_cskey_buggy(unsigned char *key)
{
sha1_key(&sha1_cs_mac_s1, &sha1_cs_mac_s2, key, 16);
}
static void sha1_sckey_buggy(unsigned char *key)
{
sha1_key(&sha1_sc_mac_s1, &sha1_sc_mac_s2, key, 16);
}
static void sha1_do_hmac(SHA_State * s1, SHA_State * s2,
unsigned char *blk, int len, unsigned long seq,
unsigned char *hmac)
static void sha1_do_hmac(void *handle, unsigned char *blk, int len,
unsigned long seq, unsigned char *hmac)
{
SHA_State *keys = (SHA_State *)handle;
SHA_State s;
unsigned char intermediate[20];
@ -249,53 +246,52 @@ static void sha1_do_hmac(SHA_State * s1, SHA_State * s2,
intermediate[2] = (unsigned char) ((seq >> 8) & 0xFF);
intermediate[3] = (unsigned char) ((seq) & 0xFF);
s = *s1; /* structure copy */
s = keys[0]; /* structure copy */
SHA_Bytes(&s, intermediate, 4);
SHA_Bytes(&s, blk, len);
SHA_Final(&s, intermediate);
s = *s2; /* structure copy */
s = keys[1]; /* structure copy */
SHA_Bytes(&s, intermediate, 20);
SHA_Final(&s, hmac);
}
static void sha1_generate(unsigned char *blk, int len, unsigned long seq)
static void sha1_generate(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
sha1_do_hmac(&sha1_cs_mac_s1, &sha1_cs_mac_s2, blk, len, seq,
blk + len);
sha1_do_hmac(handle, blk, len, seq, blk + len);
}
static int sha1_verify(unsigned char *blk, int len, unsigned long seq)
static int sha1_verify(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
unsigned char correct[20];
sha1_do_hmac(&sha1_sc_mac_s1, &sha1_sc_mac_s2, blk, len, seq, correct);
sha1_do_hmac(handle, blk, len, seq, correct);
return !memcmp(correct, blk + len, 20);
}
void hmac_sha1_simple(void *key, int keylen, void *data, int datalen,
unsigned char *output) {
SHA_State s1, s2;
SHA_State states[2];
unsigned char intermediate[20];
sha1_key(&s1, &s2, key, keylen);
SHA_Bytes(&s1, data, datalen);
SHA_Final(&s1, intermediate);
sha1_key_internal(states, key, keylen);
SHA_Bytes(&states[0], data, datalen);
SHA_Final(&states[0], intermediate);
SHA_Bytes(&s2, intermediate, 20);
SHA_Final(&s2, output);
SHA_Bytes(&states[1], intermediate, 20);
SHA_Final(&states[1], output);
}
const struct ssh_mac ssh_sha1 = {
sha1_cskey, sha1_sckey,
sha1_generate,
sha1_verify,
sha1_make_context, sha1_free_context, sha1_key,
sha1_generate, sha1_verify,
"hmac-sha1",
20
};
const struct ssh_mac ssh_sha1_buggy = {
sha1_cskey_buggy, sha1_sckey_buggy,
sha1_generate,
sha1_verify,
sha1_make_context, sha1_free_context, sha1_key_buggy,
sha1_generate, sha1_verify,
"hmac-sha1",
20
};