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Lines 44-49
RCSID("$OpenBSD: kex.c,v 1.63 2005/07/17
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#define KEX_COOKIE_LEN 16 |
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#define KEX_COOKIE_LEN 16 |
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extern const EVP_MD *evp_ssh_sha256(void); |
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/* prototype */ |
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/* prototype */ |
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static void kex_kexinit_finish(Kex *); |
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static void kex_kexinit_finish(Kex *); |
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static void kex_choose_conf(Kex *); |
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static void kex_choose_conf(Kex *); |
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Lines 294-301
choose_kex(Kex *k, char *client, char *s
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k->kex_type = KEX_DH_GRP1_SHA1; |
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k->kex_type = KEX_DH_GRP1_SHA1; |
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} else if (strcmp(k->name, KEX_DH14) == 0) { |
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} else if (strcmp(k->name, KEX_DH14) == 0) { |
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k->kex_type = KEX_DH_GRP14_SHA1; |
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k->kex_type = KEX_DH_GRP14_SHA1; |
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} else if (strcmp(k->name, KEX_DHGEX) == 0) { |
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} else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) { |
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k->kex_type = KEX_DH_GEX_SHA1; |
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k->kex_type = KEX_DH_GEX_SHA1; |
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} else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) { |
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k->kex_type = KEX_DH_GEX_SHA256; |
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} else |
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} else |
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fatal("bad kex alg %s", k->name); |
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fatal("bad kex alg %s", k->name); |
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} |
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} |
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Lines 402-429
kex_choose_conf(Kex *kex)
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} |
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} |
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static u_char * |
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static u_char * |
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derive_key(Kex *kex, int id, u_int need, u_char *hash, BIGNUM *shared_secret) |
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derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, |
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BIGNUM *shared_secret) |
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{ |
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{ |
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Buffer b; |
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Buffer b; |
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const EVP_MD *evp_md = EVP_sha1(); |
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const EVP_MD *evp_md; |
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EVP_MD_CTX md; |
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EVP_MD_CTX md; |
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char c = id; |
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char c = id; |
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u_int have; |
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u_int have; |
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int mdsz = EVP_MD_size(evp_md); |
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int mdsz; |
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u_char *digest; |
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u_char *digest; |
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buffer_init(&b); |
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buffer_put_bignum2(&b, shared_secret); |
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switch (kex->kex_type) { |
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case KEX_DH_GRP1_SHA1: |
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case KEX_DH_GRP14_SHA1: |
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case KEX_DH_GEX_SHA1: |
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evp_md = EVP_sha1(); |
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break; |
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case KEX_DH_GEX_SHA256: |
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evp_md = evp_ssh_sha256(); |
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break; |
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default: |
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fatal("derive_key: unknown kex_type %d", kex->kex_type); |
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} |
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mdsz = EVP_MD_size(evp_md); |
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if (mdsz < 0) |
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if (mdsz < 0) |
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fatal("derive_key: mdsz < 0"); |
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fatal("derive_key: mdsz < 0"); |
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digest = xmalloc(roundup(need, mdsz)); |
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digest = xmalloc(roundup(need, mdsz)); |
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buffer_init(&b); |
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buffer_put_bignum2(&b, shared_secret); |
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/* K1 = HASH(K || H || "A" || session_id) */ |
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/* K1 = HASH(K || H || "A" || session_id) */ |
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EVP_DigestInit(&md, evp_md); |
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EVP_DigestInit(&md, evp_md); |
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if (!(datafellows & SSH_BUG_DERIVEKEY)) |
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if (!(datafellows & SSH_BUG_DERIVEKEY)) |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestUpdate(&md, hash, mdsz); |
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EVP_DigestUpdate(&md, hash, hashlen); |
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EVP_DigestUpdate(&md, &c, 1); |
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EVP_DigestUpdate(&md, &c, 1); |
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EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
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EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
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EVP_DigestFinal(&md, digest, NULL); |
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EVP_DigestFinal(&md, digest, NULL); |
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Lines 433-439
derive_key(Kex *kex, int id, u_int need,
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* Kn = HASH(K || H || K1 || K2 || ... || Kn-1) |
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* Kn = HASH(K || H || K1 || K2 || ... || Kn-1) |
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* Key = K1 || K2 || ... || Kn |
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* Key = K1 || K2 || ... || Kn |
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*/ |
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*/ |
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#ifdef DEBUG_KEX |
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fprintf(stderr, "expand key: mdsz %d need %d\n", mdsz, need); |
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#endif |
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for (have = mdsz; need > have; have += mdsz) { |
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for (have = mdsz; need > have; have += mdsz) { |
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#ifdef DEBUG_KEX |
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fprintf(stderr, "expand key: have %d\n", have); |
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#endif |
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EVP_DigestInit(&md, evp_md); |
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EVP_DigestInit(&md, evp_md); |
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if (!(datafellows & SSH_BUG_DERIVEKEY)) |
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if (!(datafellows & SSH_BUG_DERIVEKEY)) |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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Lines 453-465
Newkeys *current_keys[MODE_MAX];
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#define NKEYS 6 |
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#define NKEYS 6 |
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void |
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void |
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kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) |
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kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret) |
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{ |
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{ |
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u_char *keys[NKEYS]; |
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u_char *keys[NKEYS]; |
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u_int i, mode, ctos; |
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u_int i, mode, ctos; |
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for (i = 0; i < NKEYS; i++) |
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for (i = 0; i < NKEYS; i++) { |
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keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); |
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keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, |
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shared_secret); |
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} |
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debug2("kex_derive_keys"); |
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debug2("kex_derive_keys"); |
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for (mode = 0; mode < MODE_MAX; mode++) { |
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for (mode = 0; mode < MODE_MAX; mode++) { |