Use C syntax, not FORTRAN or whatever that was :-)
[openssl.git] / ssl / ssl_sess.c
index 3872b419283db7e0057d3cbe11440a1a70ad65d7..416def8908e82ce213d6dbad5fc93ad1050d4769 100644 (file)
@@ -65,21 +65,37 @@ static void SSL_SESSION_list_remove(SSL_CTX *ctx, SSL_SESSION *s);
 static void SSL_SESSION_list_add(SSL_CTX *ctx,SSL_SESSION *s);
 static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck);
 static int ssl_session_num=0;
-static STACK *ssl_session_meth=NULL;
+static STACK_OF(CRYPTO_EX_DATA_FUNCS) *ssl_session_meth=NULL;
 
 SSL_SESSION *SSL_get_session(SSL *ssl)
+/* aka SSL_get0_session; gets 0 objects, just returns a copy of the pointer */
        {
        return(ssl->session);
        }
 
-int SSL_SESSION_get_ex_new_index(long argl, char *argp, int (*new_func)(),
-            int (*dup_func)(), void (*free_func)())
-        {
-        ssl_session_num++;
-        return(CRYPTO_get_ex_new_index(ssl_session_num-1,
+SSL_SESSION *SSL_get1_session(SSL *ssl)
+/* variant of SSL_get_session: caller really gets something */
+       {
+       SSL_SESSION *sess;
+       /* Need to lock this all up rather than just use CRYPTO_add so that
+        * somebody doesn't free ssl->session between when we check it's
+        * non-null and when we up the reference count. */
+       CRYPTO_r_lock(CRYPTO_LOCK_SSL_SESSION);
+       sess = ssl->session;
+       if(sess)
+               sess->references++;
+       CRYPTO_r_unlock(CRYPTO_LOCK_SSL_SESSION);
+       return(sess);
+       }
+
+int SSL_SESSION_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
+            CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
+       {
+       ssl_session_num++;
+       return(CRYPTO_get_ex_new_index(ssl_session_num-1,
                &ssl_session_meth,
-                argl,argp,new_func,dup_func,free_func));
-        }
+               argl,argp,new_func,dup_func,free_func));
+       }
 
 int SSL_SESSION_set_ex_data(SSL_SESSION *s, int idx, void *arg)
        {
@@ -95,7 +111,7 @@ SSL_SESSION *SSL_SESSION_new(void)
        {
        SSL_SESSION *ss;
 
-       ss=(SSL_SESSION *)Malloc(sizeof(SSL_SESSION));
+       ss=(SSL_SESSION *)OPENSSL_malloc(sizeof(SSL_SESSION));
        if (ss == NULL)
                {
                SSLerr(SSL_F_SSL_SESSION_NEW,ERR_R_MALLOC_FAILURE);
@@ -103,13 +119,14 @@ SSL_SESSION *SSL_SESSION_new(void)
                }
        memset(ss,0,sizeof(SSL_SESSION));
 
+       ss->verify_result = 1; /* avoid 0 (= X509_V_OK) just in case */
        ss->references=1;
        ss->timeout=60*5+4; /* 5 minute timeout by default */
        ss->time=time(NULL);
        ss->prev=NULL;
        ss->next=NULL;
        ss->compress_meth=0;
-       CRYPTO_new_ex_data(ssl_session_meth,(char *)ss,&ss->ex_data);
+       CRYPTO_new_ex_data(ssl_session_meth,ss,&ss->ex_data);
        return(ss);
        }
 
@@ -161,13 +178,20 @@ int ssl_get_new_session(SSL *s, int session)
                        {
                        SSL_SESSION *r;
 
-                       RAND_bytes(ss->session_id,ss->session_id_length);
+                       RAND_pseudo_bytes(ss->session_id,ss->session_id_length);
                        CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
-                       r=(SSL_SESSION *)lh_retrieve(s->ctx->sessions,
-                               (char *)ss);
+                       r=(SSL_SESSION *)lh_retrieve(s->ctx->sessions, ss);
                        CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
                        if (r == NULL) break;
                        /* else - woops a session_id match */
+                       /* XXX We should also check the external cache --
+                        * but the probability of a collision is negligible, and
+                        * we could not prevent the concurrent creation of sessions
+                        * with identical IDs since we currently don't have means
+                        * to atomically check whether a session ID already exists
+                        * and make a reservation for it if it does not
+                        * (this problem applies to the internal cache as well).
+                        */
                        }
                }
        else
@@ -179,6 +203,7 @@ int ssl_get_new_session(SSL *s, int session)
        ss->sid_ctx_length=s->sid_ctx_length;
        s->session=ss;
        ss->ssl_version=s->version;
+       ss->verify_result = X509_V_OK;
 
        return(1);
        }
@@ -188,18 +213,21 @@ int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len)
        /* This is used only by servers. */
 
        SSL_SESSION *ret=NULL,data;
+       int fatal = 0;
 
-       /* conn_init();*/
        data.ssl_version=s->version;
        data.session_id_length=len;
        if (len > SSL_MAX_SSL_SESSION_ID_LENGTH)
-               return(0);
+               goto err;
        memcpy(data.session_id,session_id,len);
 
        if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_NO_INTERNAL_LOOKUP))
                {
                CRYPTO_r_lock(CRYPTO_LOCK_SSL_CTX);
-               ret=(SSL_SESSION *)lh_retrieve(s->ctx->sessions,(char *)&data);
+               ret=(SSL_SESSION *)lh_retrieve(s->ctx->sessions,&data);
+               if (ret != NULL)
+                   /* don't allow other threads to steal it: */
+                   CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
                CRYPTO_r_unlock(CRYPTO_LOCK_SSL_CTX);
                }
 
@@ -215,27 +243,52 @@ int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len)
                        {
                        s->ctx->stats.sess_cb_hit++;
 
+                       /* Increment reference count now if the session callback
+                        * asks us to do so (note that if the session structures
+                        * returned by the callback are shared between threads,
+                        * it must handle the reference count itself [i.e. copy == 0],
+                        * or things won't be thread-safe). */
+                       if (copy)
+                               CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
+
                        /* The following should not return 1, otherwise,
                         * things are very strange */
                        SSL_CTX_add_session(s->ctx,ret);
-                       /* auto free it (decrement reference count now) */
-                       if (!copy)
-                               SSL_SESSION_free(ret);
                        }
-               if (ret == NULL) return(0);
+               if (ret == NULL)
+                       goto err;
                }
 
+       /* Now ret is non-NULL, and we own one of its reference counts. */
+
        if((s->verify_mode&SSL_VERIFY_PEER)
           && (!s->sid_ctx_length || ret->sid_ctx_length != s->sid_ctx_length
               || memcmp(ret->sid_ctx,s->sid_ctx,ret->sid_ctx_length)))
            {
-               if (s->sid_ctx_length)
-                       SSLerr(SSL_F_SSL_GET_PREV_SESSION,SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
-               else
-                       /* application should have used SSL[_CTX]_set_session_id_context */
+               /* We've found the session named by the client, but we don't
+                * want to use it in this context. */
+               
+               if (s->sid_ctx_length == 0)
+                       {
+                       /* application should have used SSL[_CTX]_set_session_id_context
+                        * -- we could tolerate this and just pretend we never heard
+                        * of this session, but then applications could effectively
+                        * disable the session cache by accident without anyone noticing */
+
                        SSLerr(SSL_F_SSL_GET_PREV_SESSION,SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
-           return 0;
-           }
+                       fatal = 1;
+                       goto err;
+                       }
+               else
+                       {
+#if 0 /* The client cannot always know when a session is not appropriate,
+          * so we shouldn't generate an error message. */
+
+                       SSLerr(SSL_F_SSL_GET_PREV_SESSION,SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT);
+#endif
+                       goto err; /* treat like cache miss */
+                       }
+               }
 
        if (ret->cipher == NULL)
                {
@@ -250,22 +303,25 @@ int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len)
                else 
                        ret->cipher=ssl_get_cipher_by_char(s,&(buf[1]));
                if (ret->cipher == NULL)
-                       return(0);
+                       goto err;
                }
 
+
+#if 0 /* This is way too late. */
+
        /* If a thread got the session, then 'swaped', and another got
-        * it and then due to a time-out decided to 'Free' it we could
+        * it and then due to a time-out decided to 'OPENSSL_free' it we could
         * be in trouble.  So I'll increment it now, then double decrement
         * later - am I speaking rubbish?. */
        CRYPTO_add(&ret->references,1,CRYPTO_LOCK_SSL_SESSION);
+#endif
 
        if ((long)(ret->time+ret->timeout) < (long)time(NULL)) /* timeout */
                {
                s->ctx->stats.sess_timeout++;
                /* remove it from the cache */
                SSL_CTX_remove_session(s->ctx,ret);
-               SSL_SESSION_free(ret);          /* again to actually Free it */
-               return(0);
+               goto err;
                }
 
        s->ctx->stats.sess_hit++;
@@ -277,7 +333,16 @@ int ssl_get_prev_session(SSL *s, unsigned char *session_id, int len)
        if (s->session != NULL)
                SSL_SESSION_free(s->session);
        s->session=ret;
+       s->verify_result = s->session->verify_result;
        return(1);
+
+ err:
+       if (ret != NULL)
+               SSL_SESSION_free(ret);
+       if (fatal)
+               return -1;
+       else
+               return 0;
        }
 
 int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
@@ -285,27 +350,47 @@ int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
        int ret=0;
        SSL_SESSION *s;
 
-       /* conn_init(); */
+       /* add just 1 reference count for the SSL_CTX's session cache
+        * even though it has two ways of access: each session is in a
+        * doubly linked list and an lhash */
        CRYPTO_add(&c->references,1,CRYPTO_LOCK_SSL_SESSION);
+       /* if session c is in already in cache, we take back the increment later */
 
        CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
-       s=(SSL_SESSION *)lh_insert(ctx->sessions,(char *)c);
+       s=(SSL_SESSION *)lh_insert(ctx->sessions,c);
        
-       /* Put on the end of the queue unless it is already in the cache */
+       /* s != NULL iff we already had a session with the given PID.
+        * In this case, s == c should hold (then we did not really modify
+        * ctx->sessions), or we're in trouble. */
+       if (s != NULL && s != c)
+               {
+               /* We *are* in trouble ... */
+               SSL_SESSION_list_remove(ctx,s);
+               SSL_SESSION_free(s);
+               /* ... so pretend the other session did not exist in cache
+                * (we cannot handle two SSL_SESSION structures with identical
+                * session ID in the same cache, which could happen e.g. when
+                * two threads concurrently obtain the same session from an external
+                * cache) */
+               s = NULL;
+               }
+
+       /* Put at the head of the queue unless it is already in the cache */
        if (s == NULL)
                SSL_SESSION_list_add(ctx,c);
 
-       /* If the same session if is being 're-added', Free the old
-        * one when the last person stops using it.
-        * This will also work if it is alread in the cache.
-        * The references will go up and then down :-) */
        if (s != NULL)
                {
-               SSL_SESSION_free(s);
+               /* existing cache entry -- decrement previously incremented reference
+                * count because it already takes into account the cache */
+
+               SSL_SESSION_free(s); /* s == c */
                ret=0;
                }
        else
                {
+               /* new cache entry -- remove old ones if cache has become too large */
+               
                ret=1;
 
                if (SSL_CTX_sess_get_cache_size(ctx) > 0)
@@ -338,7 +423,7 @@ static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
        if ((c != NULL) && (c->session_id_length != 0))
                {
                if(lck) CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
-               r=(SSL_SESSION *)lh_delete(ctx->sessions,(char *)c);
+               r=(SSL_SESSION *)lh_delete(ctx->sessions,c);
                if (r != NULL)
                        {
                        ret=1;
@@ -380,7 +465,7 @@ void SSL_SESSION_free(SSL_SESSION *ss)
                }
 #endif
 
-       CRYPTO_free_ex_data(ssl_session_meth,(char *)ss,&ss->ex_data);
+       CRYPTO_free_ex_data(ssl_session_meth,ss,&ss->ex_data);
 
        memset(ss->key_arg,0,SSL_MAX_KEY_ARG_LENGTH);
        memset(ss->master_key,0,SSL_MAX_MASTER_KEY_LENGTH);
@@ -389,7 +474,7 @@ void SSL_SESSION_free(SSL_SESSION *ss)
        if (ss->peer != NULL) X509_free(ss->peer);
        if (ss->ciphers != NULL) sk_SSL_CIPHER_free(ss->ciphers);
        memset(ss,0,sizeof(*ss));
-       Free(ss);
+       OPENSSL_free(ss);
        }
 
 int SSL_set_session(SSL *s, SSL_SESSION *session)
@@ -499,7 +584,7 @@ static void timeout(SSL_SESSION *s, TIMEOUT_PARAM *p)
                {
                /* The reason we don't call SSL_CTX_remove_session() is to
                 * save on locking overhead */
-               lh_delete(p->cache,(char *)s);
+               lh_delete(p->cache,s);
                SSL_SESSION_list_remove(p->ctx,s);
                s->not_resumable=1;
                if (p->ctx->remove_session_cb != NULL)
@@ -520,7 +605,7 @@ void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
        CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
        i=tp.cache->down_load;
        tp.cache->down_load=0;
-       lh_doall_arg(tp.cache,(void (*)())timeout,(char *)&tp);
+       lh_doall_arg(tp.cache,(void (*)())timeout,&tp);
        tp.cache->down_load=i;
        CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
        }