From 5b2586312a8793ca056294665fed597c7fc6791a Mon Sep 17 00:00:00 2001
From: Andreas Schneider <mail@cynapses.org>
Date: Thu, 16 Apr 2009 15:14:15 +0000
Subject: [PATCH] Add return values to generate_session_keys() and
 generate_one_key().

git-svn-id: svn+ssh://svn.berlios.de/svnroot/repos/libssh/trunk@508 7dcaeef0-15fb-0310-b436-a5af3365683c
---
 include/libssh/priv.h |   2 +-
 libssh/client.c       |   5 +-
 libssh/dh.c           | 185 +++++++++++++++++++++++++++---------------
 libssh/server.c       |   4 +-
 4 files changed, 128 insertions(+), 68 deletions(-)

diff --git a/include/libssh/priv.h b/include/libssh/priv.h
index 704f0b1c..5e069450 100644
--- a/include/libssh/priv.h
+++ b/include/libssh/priv.h
@@ -533,7 +533,7 @@ int make_sessionid(SSH_SESSION *session);
 /* add data for the final cookie */
 int hashbufin_add_cookie(SSH_SESSION *session, unsigned char *cookie);
 int hashbufout_add_cookie(SSH_SESSION *session);
-void generate_session_keys(SSH_SESSION *session);
+int generate_session_keys(SSH_SESSION *session);
 /* returns 1 if server signature ok, 0 otherwise. The NEXT crypto is checked, not the current one */
 int signature_verify(SSH_SESSION *session,STRING *signature);
 bignum make_string_bn(STRING *string);
diff --git a/libssh/client.c b/libssh/client.c
index f8d95d9b..a7e695f4 100644
--- a/libssh/client.c
+++ b/libssh/client.c
@@ -313,7 +313,10 @@ static int dh_handshake(SSH_SESSION *session) {
         goto error;
       }
 
-      generate_session_keys(session);
+      if (generate_session_keys(session) < 0) {
+        rc = SSH_ERROR;
+        goto error;
+      }
 
       /* Verify the host's signature. FIXME do it sooner */
       signature = session->dh_server_signature;
diff --git a/libssh/dh.c b/libssh/dh.c
index 2e766526..9a70eb4c 100644
--- a/libssh/dh.c
+++ b/libssh/dh.c
@@ -662,80 +662,135 @@ int hashbufin_add_cookie(SSH_SESSION *session, unsigned char *cookie) {
   return 0;
 }
 
-/* TODO FIXME add return value for memory checks */
-static void generate_one_key(STRING *k,unsigned char session_id[SHA_DIGEST_LEN],unsigned char output[SHA_DIGEST_LEN],char letter){
-    SHACTX ctx=sha1_init();
-    if (ctx == NULL) {
-      return;
-    }
-    sha1_update(ctx,k,string_len(k)+4);
-    sha1_update(ctx,session_id,SHA_DIGEST_LEN);
-    sha1_update(ctx,&letter,1);
-    sha1_update(ctx,session_id,SHA_DIGEST_LEN);
-    sha1_final(output,ctx);
+static int generate_one_key(STRING *k,
+    unsigned char session_id[SHA_DIGEST_LEN],
+    unsigned char output[SHA_DIGEST_LEN],
+    char letter) {
+  SHACTX ctx = NULL;
+
+  ctx = sha1_init();
+  if (ctx == NULL) {
+    return -1;
+  }
+
+  sha1_update(ctx, k, string_len(k) + 4);
+  sha1_update(ctx, session_id, SHA_DIGEST_LEN);
+  sha1_update(ctx, &letter, 1);
+  sha1_update(ctx, session_id, SHA_DIGEST_LEN);
+  sha1_final(output, ctx);
+
+  return 0;
 }
 
-/* TODO FIXME add return value for memory checks */
-void generate_session_keys(SSH_SESSION *session){
-    STRING *k_string;
-    SHACTX ctx;
-    enter_function();
-    k_string=make_bignum_string(session->next_crypto->k);
+int generate_session_keys(SSH_SESSION *session) {
+  STRING *k_string = NULL;
+  SHACTX ctx = NULL;
+  int rc = -1;
 
-    /* IV */
-    if(session->client){
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptIV,'A');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptIV,'B');
-    } else {
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptIV,'A');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptIV,'B');
-    }
-    if(session->client){
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptkey,'C');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptkey,'D');
-    } else {
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptkey,'C');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptkey,'D');
-    }
-    /* some ciphers need more than 20 bytes of input key */
-    /* XXX verify it's ok for server implementation */
-    if(session->next_crypto->out_cipher->keysize > SHA_DIGEST_LEN*8){
-        ctx=sha1_init();
-        if (ctx == NULL) {
-          leave_function();
-          return;
-        }
-        sha1_update(ctx,k_string,string_len(k_string)+4);
-        sha1_update(ctx,session->next_crypto->session_id,SHA_DIGEST_LEN);
-        sha1_update(ctx,session->next_crypto->encryptkey,SHA_DIGEST_LEN);
-        sha1_final(session->next_crypto->encryptkey+SHA_DIGEST_LEN,ctx);
-    }
+  enter_function();
 
-    if(session->next_crypto->in_cipher->keysize > SHA_DIGEST_LEN*8){
-        ctx=sha1_init();
-        sha1_update(ctx,k_string,string_len(k_string)+4);
-        sha1_update(ctx,session->next_crypto->session_id,SHA_DIGEST_LEN);
-        sha1_update(ctx,session->next_crypto->decryptkey,SHA_DIGEST_LEN);
-        sha1_final(session->next_crypto->decryptkey+SHA_DIGEST_LEN,ctx);
+  k_string = make_bignum_string(session->next_crypto->k);
+  if (k_string == NULL) {
+    goto error;
+  }
+
+  /* IV */
+  if (session->client) {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptIV, 'A') < 0) {
+      goto error;
     }
-    if(session->client){
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptMAC,'E');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptMAC,'F');
-    } else {
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->decryptMAC,'E');
-        generate_one_key(k_string,session->next_crypto->session_id,session->next_crypto->encryptMAC,'F');
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptIV, 'B') < 0) {
+      goto error;
     }
+  } else {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptIV, 'A') < 0) {
+      goto error;
+    }
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptIV, 'B') < 0) {
+      goto error;
+    }
+  }
+  if (session->client) {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptkey, 'C') < 0) {
+      goto error;
+    }
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptkey, 'D') < 0) {
+      goto error;
+    }
+  } else {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptkey, 'C') < 0) {
+      goto error;
+    }
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptkey, 'D') < 0) {
+      goto error;
+    }
+  }
+
+  /* some ciphers need more than 20 bytes of input key */
+  /* XXX verify it's ok for server implementation */
+  if (session->next_crypto->out_cipher->keysize > SHA_DIGEST_LEN * 8) {
+    ctx = sha1_init();
+    if (ctx == NULL) {
+      goto error;
+    }
+    sha1_update(ctx, k_string, string_len(k_string) + 4);
+    sha1_update(ctx, session->next_crypto->session_id, SHA_DIGEST_LEN);
+    sha1_update(ctx, session->next_crypto->encryptkey, SHA_DIGEST_LEN);
+    sha1_final(session->next_crypto->encryptkey + SHA_DIGEST_LEN, ctx);
+  }
+
+  if (session->next_crypto->in_cipher->keysize > SHA_DIGEST_LEN * 8) {
+    ctx = sha1_init();
+    sha1_update(ctx, k_string, string_len(k_string) + 4);
+    sha1_update(ctx, session->next_crypto->session_id, SHA_DIGEST_LEN);
+    sha1_update(ctx, session->next_crypto->decryptkey, SHA_DIGEST_LEN);
+    sha1_final(session->next_crypto->decryptkey + SHA_DIGEST_LEN, ctx);
+  }
+  if(session->client) {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptMAC, 'E') < 0) {
+      goto error;
+    }
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptMAC, 'F') < 0) {
+      goto error;
+    }
+  } else {
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->decryptMAC, 'E') < 0) {
+      goto error;
+    }
+    if (generate_one_key(k_string, session->next_crypto->session_id,
+          session->next_crypto->encryptMAC, 'F') < 0) {
+      goto error;
+    }
+  }
 
 #ifdef DEBUG_CRYPTO
-    ssh_print_hexa("encrypt IV",session->next_crypto->encryptIV,SHA_DIGEST_LEN);
-    ssh_print_hexa("decrypt IV",session->next_crypto->decryptIV,SHA_DIGEST_LEN);
-    ssh_print_hexa("encryption key",session->next_crypto->encryptkey,session->next_crypto->out_cipher->keysize);
-    ssh_print_hexa("decryption key",session->next_crypto->decryptkey,session->next_crypto->in_cipher->keysize);
-    ssh_print_hexa("Encryption MAC",session->next_crypto->encryptMAC,SHA_DIGEST_LEN);
-    ssh_print_hexa("Decryption MAC",session->next_crypto->decryptMAC,20);
+  ssh_print_hexa("Encrypt IV", session->next_crypto->encryptIV, SHA_DIGEST_LEN);
+  ssh_print_hexa("Decrypt IV", session->next_crypto->decryptIV, SHA_DIGEST_LEN);
+  ssh_print_hexa("Encryption key", session->next_crypto->encryptkey,
+      session->next_crypto->out_cipher->keysize);
+  ssh_print_hexa("Decryption key", session->next_crypto->decryptkey,
+      session->next_crypto->in_cipher->keysize);
+  ssh_print_hexa("Encryption MAC", session->next_crypto->encryptMAC, SHA_DIGEST_LEN);
+  ssh_print_hexa("Decryption MAC", session->next_crypto->decryptMAC, 20);
 #endif
-    free(k_string);
-    leave_function();
+
+  rc = 0;
+error:
+  string_free(k_string);
+  leave_function();
+
+  return rc;
 }
 
 /** \addtogroup ssh_session
diff --git a/libssh/server.c b/libssh/server.c
index 0a2f13fe..b1f5e3bf 100644
--- a/libssh/server.c
+++ b/libssh/server.c
@@ -330,7 +330,9 @@ static int dh_handshake_server(SSH_SESSION *session){
 
     packet_wait(session,SSH2_MSG_NEWKEYS,1);
     ssh_log(session, SSH_LOG_PACKET, "Got SSH_MSG_NEWKEYS");
-    generate_session_keys(session);
+    if (generate_session_keys(session) < 0) {
+      return -1;
+    }
     /* once we got SSH2_MSG_NEWKEYS we can switch next_crypto and current_crypto */
     if(session->current_crypto)
         crypto_free(session->current_crypto);