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-rw-r--r--crypto/openssh/rsa.c13
-rw-r--r--crypto/openssh/rsa.h2
-rw-r--r--crypto/openssh/ssh-agent.c3
-rw-r--r--crypto/openssh/sshconnect1.c9
-rw-r--r--crypto/openssh/sshd.c54
5 files changed, 53 insertions, 28 deletions
diff --git a/crypto/openssh/rsa.c b/crypto/openssh/rsa.c
index 21eec8f..3dabac1 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 e8e3803..152aa9a 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 f115d98..bbd6a78 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 96439c4..5ae46e0 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 ad69883..5073465 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);
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