diff --git a/libssh/client.c b/libssh/client.c
index b79c6058..76645e5a 100644
--- a/libssh/client.c
+++ b/libssh/client.c
@@ -213,7 +213,13 @@ static int dh_handshake(SSH_SESSION *session){
                 crypto_free(session->current_crypto);
                 /* XXX later, include a function to change keys */
             session->current_crypto=session->next_crypto;
-            session->next_crypto=crypto_new();
+
+            session->next_crypto = crypto_new();
+            if (session->next_crypto == NULL) {
+              leave_function();
+              return SSH_ERROR;
+            }
+
             session->dh_handshake_state=DH_STATE_FINISHED;
             leave_function();
             return SSH_OK;
diff --git a/libssh/crypt.c b/libssh/crypt.c
index 75c22dfd..9d8fa0f2 100644
--- a/libssh/crypt.c
+++ b/libssh/crypt.c
@@ -90,7 +90,10 @@ unsigned char * packet_encrypt(SSH_SESSION *session,void *data,u32 len){
 #endif
     out=malloc(len);
     if(session->version==2){
-        ctx=hmac_init(session->current_crypto->encryptMAC,20,HMAC_SHA1);
+        ctx = hmac_init(session->current_crypto->encryptMAC,20,HMAC_SHA1);
+        if (ctx == NULL) {
+          return NULL;
+        }
         hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
         hmac_update(ctx,data,len);
         hmac_final(ctx,session->current_crypto->hmacbuf,&finallen);
@@ -115,12 +118,16 @@ unsigned char * packet_encrypt(SSH_SESSION *session,void *data,u32 len){
         return NULL;
 }
 
+/* TODO FIXME think about the return value isn't 0 enough and -1 on error */
 int packet_hmac_verify(SSH_SESSION *session,BUFFER *buffer,unsigned char *mac){
     HMACCTX ctx;
     unsigned char hmacbuf[EVP_MAX_MD_SIZE];
     unsigned int len;
     u32 seq=htonl(session->recv_seq);
     ctx=hmac_init(session->current_crypto->decryptMAC,20,HMAC_SHA1);
+    if (ctx == NULL) {
+      return -1;
+    }
     hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
     hmac_update(ctx,buffer_get(buffer),buffer_get_len(buffer));
     hmac_final(ctx,hmacbuf,&len);
diff --git a/libssh/dh.c b/libssh/dh.c
index 377cfe34..c89c7c81 100644
--- a/libssh/dh.c
+++ b/libssh/dh.c
@@ -355,6 +355,8 @@ static void sha_add(STRING *str,SHACTX ctx){
 #endif
 }
 */
+
+/* TODO FIXME add memory checking and a return value */
 void make_sessionid(SSH_SESSION *session){
     SHACTX ctx;
     STRING *num,*str;
@@ -362,7 +364,11 @@ void make_sessionid(SSH_SESSION *session){
     BUFFER *buf=buffer_new();
     u32 len;
     enter_function();
-    ctx=sha1_init();
+
+    ctx = sha1_init();
+    if (ctx == NULL) {
+      return;
+    }
 
     str=string_from_char(session->clientbanner);
     buffer_add_ssh_string(buf,str);
@@ -450,8 +456,12 @@ void hashbufin_add_cookie(SSH_SESSION *session,unsigned char *cookie){
     buffer_add_data(session->in_hashbuf,cookie,16);
 }
 
+/* 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);
@@ -459,6 +469,7 @@ static void generate_one_key(STRING *k,unsigned char session_id[SHA_DIGEST_LEN],
     sha1_final(output,ctx);
 }
 
+/* TODO FIXME add return value for memory checks */
 void generate_session_keys(SSH_SESSION *session){
     STRING *k_string;
     SHACTX ctx;
@@ -484,6 +495,9 @@ void generate_session_keys(SSH_SESSION *session){
     /* 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) {
+          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);
@@ -533,6 +547,10 @@ int ssh_get_pubkey_hash(SSH_SESSION *session,unsigned char hash[MD5_DIGEST_LEN])
     int len=string_len(pubkey);
 
     ctx=md5_init();
+    if (ctx == NULL) {
+      return 0;
+    }
+
     md5_update(ctx,pubkey->string,len);
     md5_final(hash,ctx);
     return MD5_DIGEST_LEN;
diff --git a/libssh/kex.c b/libssh/kex.c
index db86c8cb..e325aeda 100644
--- a/libssh/kex.c
+++ b/libssh/kex.c
@@ -353,9 +353,17 @@ static STRING *make_rsa1_string(STRING *e, STRING *n){
     return ret;
 }
 
+/* TODO FIXME add return value and error checking in callers */
 static void build_session_id1(SSH_SESSION *session, STRING *servern, 
         STRING *hostn){
-    MD5CTX md5=md5_init();
+    MD5CTX md5;
+
+    md5 = md5_init();
+    if (md5 == NULL) {
+      return;
+    }
+
+
 #ifdef DEBUG_CRYPTO
     ssh_print_hexa("host modulus",hostn->string,string_len(hostn));
     ssh_print_hexa("server modulus",servern->string,string_len(servern));
diff --git a/libssh/keyfiles.c b/libssh/keyfiles.c
index cefcc98a..d91d0351 100644
--- a/libssh/keyfiles.c
+++ b/libssh/keyfiles.c
@@ -993,10 +993,14 @@ static int match_hashed_host(SSH_SESSION *session, char *host, char *sourcehash)
 	if(strncmp(sourcehash,"|1|",3) != 0)
 		return 0;
 	source=strdup(sourcehash+3);
+        if (source == NULL) {
+          leave_function();
+          return 0;
+        }
 	b64hash=strchr(source,'|');
 	if(!b64hash){
 		/* Invalid hash */
-		free(source);
+		SAFE_FREE(source);
 		leave_function();
 		return 0;
 	}
@@ -1006,6 +1010,11 @@ static int match_hashed_host(SSH_SESSION *session, char *host, char *sourcehash)
 	hash=base64_to_bin(b64hash);
 	free(source);
 	mac=hmac_init(buffer_get(salt),buffer_get_len(salt),HMAC_SHA1);
+        if (mac == NULL) {
+          SAFE_FREE(source);
+          leave_function();
+          return 0;
+        }
 	hmac_update(mac,host,strlen(host));
 	hmac_final(mac,buffer,&size);
 	if(size == buffer_get_len(hash) && memcmp(buffer,buffer_get(hash),size)==0)
diff --git a/libssh/keys.c b/libssh/keys.c
index 82d5ce39..cdef39fc 100644
--- a/libssh/keys.c
+++ b/libssh/keys.c
@@ -715,7 +715,11 @@ STRING *ssh_do_sign(SSH_SESSION *session,BUFFER *sigbuf, PRIVATE_KEY *privatekey
       return NULL;
     }
     string_fill(session_str,crypto->session_id,SHA_DIGEST_LEN);
-    ctx=sha1_init();
+    ctx = sha1_init();
+    if (ctx == NULL) {
+      SAFE_FREE(session_str);
+      return NULL;
+    }
     sha1_update(ctx,session_str,string_len(session_str)+4);
     SAFE_FREE(session_str);
     sha1_update(ctx,buffer_get(sigbuf),buffer_get_len(sigbuf));
@@ -818,7 +822,10 @@ STRING *ssh_sign_session_id(SSH_SESSION *session, PRIVATE_KEY *privatekey){
 #ifdef HAVE_LIBGCRYPT
     gcry_sexp_t data_sexp;
 #endif
-    ctx=sha1_init();
+    ctx = sha1_init();
+    if (ctx == NULL) {
+      return NULL;
+    }
     sha1_update(ctx,crypto->session_id,SHA_DIGEST_LEN);
     sha1_final(hash+1,ctx);
     hash[0]=0;
diff --git a/libssh/server.c b/libssh/server.c
index 65903dee..6cc0087b 100644
--- a/libssh/server.c
+++ b/libssh/server.c
@@ -307,7 +307,10 @@ static int dh_handshake_server(SSH_SESSION *session){
         crypto_free(session->current_crypto);
     /* XXX later, include a function to change keys */
     session->current_crypto=session->next_crypto;
-    session->next_crypto=crypto_new();
+    session->next_crypto = crypto_new();
+    if (session->next_crypto == NULL) {
+      return -1;
+    }
     return 0;
 }
 /* do the banner and key exchange */
diff --git a/libssh/session.c b/libssh/session.c
index 6c88c6c2..02eaf0b7 100644
--- a/libssh/session.c
+++ b/libssh/session.c
@@ -43,6 +43,9 @@ SSH_SESSION *ssh_new(void) {
     SSH_SESSION *session=malloc(sizeof (SSH_SESSION));
     memset(session,0,sizeof(SSH_SESSION));
     session->next_crypto=crypto_new();
+    if (session->next_crypto == NULL) {
+      goto err;
+    }
     session->maxchannel=FIRST_CHANNEL;
     session->socket = ssh_socket_new(session);
     if (session->socket == NULL) {
diff --git a/libssh/wrapper.c b/libssh/wrapper.c
index 5c8d9b3c..fd47c7ad 100644
--- a/libssh/wrapper.c
+++ b/libssh/wrapper.c
@@ -38,6 +38,17 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+
+/* TODO FIXME */
+static int alloc_key(struct crypto_struct *cipher) {
+    cipher->key = malloc(cipher->keylen);
+    if (cipher->key == NULL) {
+      return -1;
+    }
+
+    return 0;
+}
+
 #ifdef HAVE_LIBGCRYPT
 #include <gcrypt.h>
 
@@ -97,17 +108,16 @@ void hmac_final(HMACCTX c,unsigned char *hashmacbuf,unsigned int *len){
     gcry_md_close(c);
 }
 
-static void alloc_key(struct crypto_struct *cipher){
-    cipher->key=malloc(cipher->keylen);
-}
-
 /* the wrapper functions for blowfish */
 static void blowfish_set_key(struct crypto_struct *cipher, void *key, void *IV){
-    if(!cipher->key){
-        alloc_key(cipher);
-        gcry_cipher_open(&cipher->key[0],GCRY_CIPHER_BLOWFISH,GCRY_CIPHER_MODE_CBC,0);
-        gcry_cipher_setkey(cipher->key[0],key,16);
-        gcry_cipher_setiv(cipher->key[0],IV,8);
+    if(cipher->key == NULL) {
+      /* TODO FIXME */
+      if (alloc_key(cipher) < 0) {
+        return;
+      }
+      gcry_cipher_open(&cipher->key[0],GCRY_CIPHER_BLOWFISH,GCRY_CIPHER_MODE_CBC,0);
+      gcry_cipher_setkey(cipher->key[0],key,16);
+      gcry_cipher_setiv(cipher->key[0],IV,8);
     }
 }
 
@@ -121,7 +131,10 @@ static void blowfish_decrypt(struct crypto_struct *cipher, void *in, void *out,
 
 static void aes_set_key(struct crypto_struct *cipher, void *key, void *IV){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         switch(cipher->keysize){
           case 128:
             gcry_cipher_open(&cipher->key[0],GCRY_CIPHER_AES128,GCRY_CIPHER_MODE_CBC,0);
@@ -148,7 +161,10 @@ static void aes_decrypt(struct crypto_struct *cipher, void *in, void *out,unsign
 
 static void des3_set_key(struct crypto_struct *cipher, void *key, void *IV){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         gcry_cipher_open(&cipher->key[0],GCRY_CIPHER_3DES,GCRY_CIPHER_MODE_CBC,0);
         gcry_cipher_setkey(cipher->key[0],key,24);
         gcry_cipher_setiv(cipher->key[0],IV,8);
@@ -167,7 +183,10 @@ static void des3_decrypt(struct crypto_struct *cipher, void *in, void *out,
 
 static void des3_1_set_key(struct crypto_struct *cipher, void *key, void *IV){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         gcry_cipher_open(&cipher->key[0],GCRY_CIPHER_DES,GCRY_CIPHER_MODE_CBC,0);
         gcry_cipher_setkey(cipher->key[0],key,8);
         gcry_cipher_setiv(cipher->key[0],IV,8);
@@ -231,7 +250,10 @@ static struct crypto_struct ssh_ciphertab[]={
 #endif
 
 SHACTX sha1_init(){
-    SHACTX c=malloc(sizeof(*c));
+    SHACTX c = malloc(sizeof(*c));
+    if (c == NULL) {
+      return NULL;
+    }
     SHA1_Init(c);
     return c;
 }
@@ -247,7 +269,10 @@ void sha1(unsigned char *digest,int len,unsigned char *hash){
 }
 
 MD5CTX md5_init(){
-    MD5CTX c=malloc(sizeof(*c));
+    MD5CTX c = malloc(sizeof(*c));
+    if (c == NULL) {
+      return NULL;
+    }
     MD5_Init(c);
     return c;
 }
@@ -261,7 +286,11 @@ void md5_final(unsigned char *md,MD5CTX c){
 
 HMACCTX hmac_init(const void *key, int len,int type){
     HMACCTX ctx;
-    ctx=malloc(sizeof(*ctx));
+
+    ctx = malloc(sizeof(*ctx));
+    if (ctx == NULL) {
+      return NULL;
+    }
 #ifndef OLD_CRYPTO
     HMAC_CTX_init(ctx); // openssl 0.9.7 requires it.
 #endif
@@ -291,15 +320,14 @@ void hmac_final(HMACCTX ctx,unsigned char *hashmacbuf,unsigned int *len){
    free(ctx);
 }
 
-static void alloc_key(struct crypto_struct *cipher){
-    cipher->key=malloc(cipher->keylen);
-}
-
 #ifdef HAS_BLOWFISH
 /* the wrapper functions for blowfish */
 static void blowfish_set_key(struct crypto_struct *cipher, void *key){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         BF_set_key(cipher->key,16,key);
     }
 }
@@ -315,13 +343,19 @@ static void blowfish_decrypt(struct crypto_struct *cipher, void *in, void *out,u
 #ifdef HAS_AES
 static void aes_set_encrypt_key(struct crypto_struct *cipher, void *key){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         AES_set_encrypt_key(key,cipher->keysize,cipher->key);
     }
 }
 static void aes_set_decrypt_key(struct crypto_struct *cipher, void *key){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         AES_set_decrypt_key(key,cipher->keysize,cipher->key);
     }
 }
@@ -335,7 +369,10 @@ static void aes_decrypt(struct crypto_struct *cipher, void *in, void *out, unsig
 #ifdef HAS_DES
 static void des3_set_key(struct crypto_struct *cipher, void *key){
     if(!cipher->key){
-        alloc_key(cipher);
+        /* TODO FIXME */
+        if (alloc_key(cipher) < 0) {
+          return;
+        }
         DES_set_odd_parity(key);
         DES_set_odd_parity(key+8);
         DES_set_odd_parity(key+16);
@@ -413,7 +450,13 @@ static struct crypto_struct ssh_ciphertab[]={
 
 /* it allocates a new cipher structure based on its offset into the global table */
 static struct crypto_struct *cipher_new(int offset){
-    struct crypto_struct *cipher=malloc(sizeof(struct crypto_struct));
+    struct crypto_struct *cipher;
+
+    cipher = malloc(sizeof(struct crypto_struct));
+    if (cipher == NULL) {
+      return NULL;
+    }
+
     /* note the memcpy will copy the pointers : so, you shouldn't free them */
     memcpy(cipher,&ssh_ciphertab[offset],sizeof(*cipher));
     return cipher;
@@ -436,10 +479,17 @@ static void cipher_free(struct crypto_struct *cipher){
     free(cipher);
 }
 
-CRYPTO *crypto_new(void){
-    CRYPTO *crypto=malloc(sizeof (CRYPTO));
-    memset(crypto,0,sizeof(*crypto));
-    return crypto;
+CRYPTO *crypto_new(void) {
+  CRYPTO *crypto;
+
+  crypto = malloc(sizeof (CRYPTO));
+  if (crypto == NULL) {
+    return NULL;
+  }
+
+  ZERO_STRUCTP(crypto);
+
+  return crypto;
 }
 
 void crypto_free(CRYPTO *crypto){
@@ -477,7 +527,13 @@ static int crypt_set_algorithms2(SSH_SESSION *session){
         return SSH_ERROR;
     }
     ssh_log(session,SSH_LOG_PACKET,"Set output algorithm %s",wanted);
-    session->next_crypto->out_cipher=cipher_new(i);
+
+    session->next_crypto->out_cipher = cipher_new(i);
+    if (session->next_crypto->out_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      return SSH_ERROR;
+    }
+
     i=0;
     /* in */
     wanted=session->client_kex.methods[SSH_CRYPT_S_C];
@@ -488,7 +544,13 @@ static int crypt_set_algorithms2(SSH_SESSION *session){
         return SSH_ERROR;
     }
     ssh_log(session,SSH_LOG_PACKET,"Set input algorithm %s",wanted);
-    session->next_crypto->in_cipher=cipher_new(i);
+
+    session->next_crypto->in_cipher = cipher_new(i);
+    if (session->next_crypto->in_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      return SSH_ERROR;
+    }
+
     /* compression */
     if(strstr(session->client_kex.methods[SSH_COMP_C_S],"zlib"))
         session->next_crypto->do_compress_out=1;
@@ -506,8 +568,19 @@ static int crypt_set_algorithms1(SSH_SESSION *session){
         ssh_set_error(session,SSH_FATAL,"cipher 3des-cbc-ssh1 not found !");
         return -1;
     }
-    session->next_crypto->out_cipher=cipher_new(i);
-    session->next_crypto->in_cipher=cipher_new(i);
+
+    session->next_crypto->out_cipher = cipher_new(i);
+    if (session->next_crypto->out_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      return SSH_ERROR;
+    }
+
+    session->next_crypto->in_cipher = cipher_new(i);
+    if (session->next_crypto->in_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      return SSH_ERROR;
+    }
+
     return SSH_OK;
 }
 
@@ -545,8 +618,14 @@ int crypt_set_algorithms_server(SSH_SESSION *session){
         return SSH_ERROR;
     }
     ssh_log(session,SSH_LOG_PACKET,"Set output algorithm %s",match);
-    session->next_crypto->out_cipher=cipher_new(i);
-    free(match);
+    SAFE_FREE(match);
+
+    session->next_crypto->out_cipher = cipher_new(i);
+    if (session->next_crypto->out_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      leave_function();
+      return SSH_ERROR;
+    }
     i=0;
     /* in */
     client=session->client_kex.methods[SSH_CRYPT_C_S];
@@ -567,8 +646,15 @@ int crypt_set_algorithms_server(SSH_SESSION *session){
         return SSH_ERROR;
     }
     ssh_log(session,SSH_LOG_PACKET,"Set input algorithm %s",match);
-    session->next_crypto->in_cipher=cipher_new(i);
-    free(match);
+    SAFE_FREE(match);
+
+    session->next_crypto->in_cipher = cipher_new(i);
+    if (session->next_crypto->in_cipher == NULL) {
+      ssh_set_error(session, SSH_FATAL, "No space left");
+      leave_function();
+      return SSH_ERROR;
+    }
+
     /* compression */
     client=session->client_kex.methods[SSH_CRYPT_C_S];
     server=session->server_kex.methods[SSH_CRYPT_C_S];