diff options
-rw-r--r-- | crypto/openssh/rsa.c | 13 | ||||
-rw-r--r-- | crypto/openssh/rsa.h | 2 | ||||
-rw-r--r-- | crypto/openssh/ssh-agent.c | 3 | ||||
-rw-r--r-- | crypto/openssh/sshconnect1.c | 9 | ||||
-rw-r--r-- | crypto/openssh/sshd.c | 54 |
5 files changed, 53 insertions, 28 deletions
diff --git a/crypto/openssh/rsa.c b/crypto/openssh/rsa.c index 21eec8f482d0..3dabac1aab42 100644 --- a/crypto/openssh/rsa.c +++ b/crypto/openssh/rsa.c @@ -161,7 +161,7 @@ rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key) xfree(inbuf); } -void +int rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key) { unsigned char *inbuf, *outbuf; @@ -175,15 +175,16 @@ rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key) BN_bn2bin(in, inbuf); if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key, - RSA_PKCS1_PADDING)) <= 0) - fatal("rsa_private_decrypt() failed."); - - BN_bin2bn(outbuf, len, out); - + RSA_PKCS1_PADDING)) <= 0) { + error("rsa_private_decrypt() failed"); + } else { + BN_bin2bn(outbuf, len, out); + } memset(outbuf, 0, olen); memset(inbuf, 0, ilen); xfree(outbuf); xfree(inbuf); + return len; } /* Set whether to output verbose messages during key generation. */ diff --git a/crypto/openssh/rsa.h b/crypto/openssh/rsa.h index e8e380356176..152aa9af0ec2 100644 --- a/crypto/openssh/rsa.h +++ b/crypto/openssh/rsa.h @@ -32,6 +32,6 @@ void rsa_set_verbose __P((int verbose)); int rsa_alive __P((void)); void rsa_public_encrypt __P((BIGNUM * out, BIGNUM * in, RSA * prv)); -void rsa_private_decrypt __P((BIGNUM * out, BIGNUM * in, RSA * prv)); +int rsa_private_decrypt __P((BIGNUM * out, BIGNUM * in, RSA * prv)); #endif /* RSA_H */ diff --git a/crypto/openssh/ssh-agent.c b/crypto/openssh/ssh-agent.c index f115d988a284..bbd6a782874a 100644 --- a/crypto/openssh/ssh-agent.c +++ b/crypto/openssh/ssh-agent.c @@ -194,7 +194,8 @@ process_authentication_challenge1(SocketEntry *e) private = lookup_private_key(key, NULL, 1); if (private != NULL) { /* Decrypt the challenge using the private key. */ - rsa_private_decrypt(challenge, challenge, private->rsa); + if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) + goto failure; /* The response is MD5 of decrypted challenge plus session id. */ len = BN_num_bytes(challenge); diff --git a/crypto/openssh/sshconnect1.c b/crypto/openssh/sshconnect1.c index 96439c467695..5ae46e0fa0a5 100644 --- a/crypto/openssh/sshconnect1.c +++ b/crypto/openssh/sshconnect1.c @@ -152,14 +152,17 @@ respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) int i, len; /* Decrypt the challenge using the private key. */ - rsa_private_decrypt(challenge, challenge, prv); + /* XXX think about Bleichenbacher, too */ + if (rsa_private_decrypt(challenge, challenge, prv) <= 0) + packet_disconnect( + "respond_to_rsa_challenge: rsa_private_decrypt failed"); /* Compute the response. */ /* The response is MD5 of decrypted challenge plus session id. */ len = BN_num_bytes(challenge); if (len <= 0 || len > sizeof(buf)) - packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", - len); + packet_disconnect( + "respond_to_rsa_challenge: bad challenge length %d", len); memset(buf, 0, sizeof(buf)); BN_bn2bin(challenge, buf + sizeof(buf) - len); diff --git a/crypto/openssh/sshd.c b/crypto/openssh/sshd.c index ad69883f0ff1..5073465cd992 100644 --- a/crypto/openssh/sshd.c +++ b/crypto/openssh/sshd.c @@ -1108,6 +1108,7 @@ do_ssh1_kex() { int i, len; int plen, slen; + int rsafail = 0; BIGNUM *session_key_int; unsigned char session_key[SSH_SESSION_KEY_LENGTH]; unsigned char cookie[8]; @@ -1229,7 +1230,7 @@ do_ssh1_kex() * with larger modulus first). */ if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) { - /* Private key has bigger modulus. */ + /* Server key has bigger modulus. */ if (BN_num_bits(sensitive_data.private_key->n) < BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) { fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", @@ -1238,10 +1239,12 @@ do_ssh1_kex() BN_num_bits(sensitive_data.host_key->n), SSH_KEY_BITS_RESERVED); } - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.private_key); - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.host_key); + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.private_key) <= 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.host_key) <= 0) + rsafail++; } else { /* Host key has bigger modulus (or they are equal). */ if (BN_num_bits(sensitive_data.host_key->n) < @@ -1252,10 +1255,12 @@ do_ssh1_kex() BN_num_bits(sensitive_data.private_key->n), SSH_KEY_BITS_RESERVED); } - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.host_key); - rsa_private_decrypt(session_key_int, session_key_int, - sensitive_data.private_key); + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.host_key) < 0) + rsafail++; + if (rsa_private_decrypt(session_key_int, session_key_int, + sensitive_data.private_key) < 0) + rsafail++; } compute_session_id(session_id, cookie, @@ -1270,14 +1275,29 @@ do_ssh1_kex() * least significant 256 bits of the integer; the first byte of the * key is in the highest bits. */ - BN_mask_bits(session_key_int, sizeof(session_key) * 8); - len = BN_num_bytes(session_key_int); - if (len < 0 || len > sizeof(session_key)) - fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d", - get_remote_ipaddr(), - len, sizeof(session_key)); - memset(session_key, 0, sizeof(session_key)); - BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len); + if (!rsafail) { + BN_mask_bits(session_key_int, sizeof(session_key) * 8); + len = BN_num_bytes(session_key_int); + if (len < 0 || len > sizeof(session_key)) { + error("do_connection: bad session key len from %s: " + "session_key_int %d > sizeof(session_key) %d", + get_remote_ipaddr(), len, sizeof(session_key)); + rsafail++; + } else { + memset(session_key, 0, sizeof(session_key)); + BN_bn2bin(session_key_int, + session_key + sizeof(session_key) - len); + } + } + if (rsafail) { + log("do_connection: generating a fake encryption key"); + for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { + if (i % 4 == 0) + rand = arc4random(); + session_key[i] = rand & 0xff; + rand >>= 8; + } + } /* Destroy the decrypted integer. It is no longer needed. */ BN_clear_free(session_key_int); |