+/*
+ * Copyright (c) 1999-2001,2005-2008,2010-2014 Apple Inc. All Rights Reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+/*
+ * appleSession.c - Session storage module, Apple CDSA version.
+ */
+
+/*
+ * The current implementation stores sessions in a linked list, a member of a
+ * SessionCache object for which we keep a single global instance. It is
+ * expected that at a given time, only a small number of sessions will be
+ * cached, so the random insertion access provided by a map<> is unnecessary.
+ * New entries are placed in the head of the list, assuming a LIFO usage
+ * tendency.
+ *
+ * Entries in this cache have a time to live of SESSION_CACHE_TTL, currently
+ * ten minutes. Entries are tested for being stale upon lookup; also, the global
+ * sslCleanupSession() tests all entries in the cache, deleting entries which
+ * are stale. This function is currently called whenever an SSLContext is deleted.
+ * The current design does not provide any asynchronous timed callouts to perform
+ * further cache cleanup; it was decided that the thread overhead of this would
+ * outweight the benefits (again assuming a small number of entries in the
+ * cache).
+ *
+ * When a session is added via sslAddSession, and a cache entry already
+ * exists for the specifed key (sessionID), the sessionData for the existing
+ * cache entry is updated with the new sessionData. The entry's expiration
+ * time is unchanged (thus a given session entry can only be used for a finite
+ * time no mattter how often it is re-used),
+ */
+
+#include "ssl.h"
+#include "sslMemory.h"
+#include "sslDebug.h"
+#include "appleSession.h"
+
+#include <CoreFoundation/CFDate.h>
+#include <pthread.h>
+#include <string.h>
+
+#include <utilities/SecIOFormat.h>
+
+/* default time-to-live in cache, in seconds */
+#define QUICK_CACHE_TEST 0
+#if QUICK_CACHE_TEST
+#define SESSION_CACHE_TTL ((CFTimeInterval)5)
+#else
+#define SESSION_CACHE_TTL ((CFTimeInterval)(10 * 60))
+#endif /* QUICK_CACHE_TEST */
+
+#define CACHE_PRINT 0
+#if CACHE_PRINT
+#define DUMP_ALL_CACHE 0
+
+static void cachePrint(
+ const void *entry,
+ const SSLBuffer *key,
+ const SSLBuffer *data)
+{
+ printf("entry: %p ", entry);
+ unsigned char *kd = key->data;
+ if(data != NULL) {
+ unsigned char *dd = data->data;
+ printf(" key: %02X%02X%02X%02X%02X%02X%02X%02X"
+ " data: %02X%02X%02X%02X... (len %d)\n",
+ kd[0],kd[1],kd[2],kd[3], kd[4],kd[5],kd[6],kd[7],
+ dd[0],dd[1],dd[2],dd[3], (unsigned)data->length);
+ }
+ else {
+ /* just print key */
+ printf(" key: %02X%02X%02X%02X%02X%02X%02X%02X\n",
+ kd[0],kd[1],kd[2],kd[3], kd[4],kd[5],kd[6],kd[7]);
+ }
+}
+#else /* !CACHE_PRINT */
+#define cachePrint(e, k, d)
+#define DUMP_ALL_CACHE 0
+#endif /* CACHE_PRINT */
+
+#if DUMP_ALL_CACHE
+static void dumpAllCache(void);
+#else
+#define dumpAllCache()
+#endif
+
+/*
+ * One entry (value) in SessionCache.
+ */
+typedef struct SessionCacheEntry SessionCacheEntry;
+struct SessionCacheEntry {
+ /* Linked list of SessionCacheEntries. */
+ SessionCacheEntry *next;
+
+ SSLBuffer mKey;
+ SSLBuffer mSessionData;
+
+ /* this entry to be removed from session map at this time */
+ CFAbsoluteTime mExpiration;
+};
+
+/*
+ * Note: the caller passes in the expiration time solely to accomodate the
+ * instantiation of a single const Time::Interval for use in calculating
+ * TTL. This const, SessionCache.mTimeToLive, is in the singleton gSession Cache.
+ */
+/*
+ * This constructor, the only one, allocs copies of the key and value
+ * SSLBuffers.
+ */
+static SessionCacheEntry *SessionCacheEntryCreate(
+ const SSLBuffer *key,
+ const SSLBuffer *sessionData,
+ CFAbsoluteTime expirationTime)
+{
+ OSStatus serr;
+
+ SessionCacheEntry *entry = sslMalloc(sizeof(SessionCacheEntry));
+ if (entry == NULL)
+ return NULL;
+
+ serr = SSLCopyBuffer(key, &entry->mKey);
+ if(serr) {
+ sslFree (entry);
+ return NULL;
+ }
+ serr = SSLCopyBuffer(sessionData, &entry->mSessionData);
+ if(serr) {
+ SSLFreeBuffer(&entry->mKey);
+ sslFree (entry);
+ return NULL;
+ }
+
+ sslLogSessCacheDebug("SessionCacheEntryCreate(buf,buf) %p", entry);
+ entry->mExpiration = expirationTime;
+
+ return entry;
+}
+
+static void SessionCacheEntryDelete(SessionCacheEntry *entry)
+{
+ sslLogSessCacheDebug("~SessionCacheEntryDelete() %p", entry);
+ SSLFreeBuffer(&entry->mKey); // no SSLContext
+ SSLFreeBuffer(&entry->mSessionData);
+ sslFree(entry);
+}
+
+/* basic lookup/match function */
+static bool SessionCacheEntryMatchKey(SessionCacheEntry *entry,
+ const SSLBuffer *key)
+{
+ if(key->length != entry->mKey.length) {
+ return false;
+ }
+ if((key->data == NULL) || (entry->mKey.data == NULL)) {
+ return false;
+ }
+ return (memcmp(key->data, entry->mKey.data, entry->mKey.length) == 0);
+}
+
+static bool SessionCacheEntryIsStale(SessionCacheEntry *entry,
+ CFAbsoluteTime now)
+{
+ return now > entry->mExpiration;
+}
+
+/* has this expired? */
+static bool SessionCacheEntryIsStaleNow(SessionCacheEntry *entry)
+{
+ return SessionCacheEntryIsStale(entry, CFAbsoluteTimeGetCurrent());
+}
+
+/* replace existing mSessionData */
+static OSStatus SessionCacheEntrySetSessionData(SessionCacheEntry *entry,
+ const SSLBuffer *data)
+{
+ SSLFreeBuffer(&entry->mSessionData);
+ return SSLCopyBuffer(data, &entry->mSessionData);
+}
+
+/*
+ * Global list of sessions and associated state. We maintain a singleton of
+ * this.
+ */
+typedef struct SessionCache {
+ SessionCacheEntry *head;
+ CFTimeInterval mTimeToLive; /* default time-to-live in seconds */
+} SessionCache;
+
+static pthread_mutex_t gSessionCacheLock = PTHREAD_MUTEX_INITIALIZER;
+static SessionCache *gSessionCache = NULL;
+
+static void SessionCacheInit(void) {
+ gSessionCache = sslMalloc(sizeof(SessionCache));
+ gSessionCache->head = NULL;
+ gSessionCache->mTimeToLive = SESSION_CACHE_TTL;
+}
+
+static SessionCache *SessionCacheGetLockedInstance(void) {
+ pthread_mutex_lock(&gSessionCacheLock);
+ if (!gSessionCache) {
+ /* We could use pthread_once, but we already have a mutex for other
+ reasons. */
+ SessionCacheInit();
+ }
+
+ return gSessionCache;
+}
+
+/* these three correspond to the C functions exported by this file */
+static OSStatus SessionCacheAddEntry(
+ SessionCache *cache,
+ const SSLBuffer *sessionKey,
+ const SSLBuffer *sessionData,
+ uint32_t timeToLive) /* optional time-to-live in seconds; 0 ==> default */
+{
+ SessionCacheEntry *entry = NULL;
+ SessionCacheEntry **current;
+ CFTimeInterval expireTime;
+
+ for (current = &(cache->head); *current; current = &((*current)->next)) {
+ entry = *current;
+ if (SessionCacheEntryMatchKey(entry, sessionKey)) {
+ /* cache hit - just update this entry's sessionData if necessary */
+ /* Note we leave expiration time and position in queue unchanged
+ - OK? */
+ /* What if the entry has already expired? */
+ if((entry->mSessionData.length == sessionData->length) &&
+ (memcmp(entry->mSessionData.data, sessionData->data,
+ sessionData->length) == 0)) {
+ /*
+ * These usually match, and a memcmp is a lot cheaper than
+ * a malloc and a free, hence this quick optimization.....
+ */
+ sslLogSessCacheDebug("SessionCache::addEntry CACHE HIT "
+ "entry = %p", entry);
+ return errSecSuccess;
+ }
+ else {
+ sslLogSessCacheDebug("SessionCache::addEntry CACHE REPLACE "
+ "entry = %p", entry);
+ return SessionCacheEntrySetSessionData(entry, sessionData);
+ }
+ }
+ }
+
+ expireTime = CFAbsoluteTimeGetCurrent();
+ if(timeToLive) {
+ /* caller-specified */
+ expireTime += (CFTimeInterval)timeToLive;
+ }
+ else {
+ /* default */
+ expireTime += cache->mTimeToLive;
+ }
+ /* this allocs new copy of incoming sessionKey and sessionData */
+ entry = SessionCacheEntryCreate(sessionKey, sessionData, expireTime);
+
+ sslLogSessCacheDebug("SessionCache::addEntry %p", entry);
+ cachePrint(entry, sessionKey, sessionData);
+ dumpAllCache();
+
+ /* add to head of queue for LIFO caching */
+ entry->next = cache->head;
+ cache->head = entry;
+
+ return errSecSuccess;
+}
+
+static OSStatus SessionCacheLookupEntry(
+ SessionCache *cache,
+ const SSLBuffer *sessionKey,
+ SSLBuffer *sessionData)
+{
+ SessionCacheEntry *entry = NULL;
+ SessionCacheEntry **current;
+ for (current = &(cache->head); *current; current = &((*current)->next)) {
+ entry = *current;
+ if (SessionCacheEntryMatchKey(entry, sessionKey))
+ break;
+ }
+
+ if (*current == NULL)
+ return errSSLSessionNotFound;
+
+ if (SessionCacheEntryIsStaleNow(entry)) {
+ sslLogSessCacheDebug("SessionCache::lookupEntry %p: STALE "
+ "entry, deleting; current %p, entry->next %p",
+ entry, current, entry->next);
+ cachePrint(entry, sessionKey, &entry->mSessionData);
+ *current = entry->next;
+ SessionCacheEntryDelete(entry);
+ return errSSLSessionNotFound;
+ }
+
+ /* alloc/copy sessionData from existing entry (caller must free) */
+ return SSLCopyBuffer(&entry->mSessionData, sessionData);
+}
+
+static OSStatus SessionCacheDeleteEntry(
+ SessionCache *cache,
+ const SSLBuffer *sessionKey)
+{
+ SessionCacheEntry **current;
+
+ for (current = &(cache->head); *current; current = &((*current)->next)) {
+ SessionCacheEntry *entry = *current;
+ if (SessionCacheEntryMatchKey(entry, sessionKey)) {
+ #ifndef DEBUG
+ sslLogSessCacheDebug("...SessionCacheDeleteEntry: deleting "
+ "cached session (%p)", entry);
+ cachePrint(entry, &entry->mKey, &entry->mSessionData);
+ #endif
+ *current = entry->next;
+ SessionCacheEntryDelete(entry);
+ return errSecSuccess;
+ }
+ }
+
+ return errSecSuccess;
+}
+
+/* cleanup, delete stale entries */
+static bool SessionCacheCleanup(SessionCache *cache)
+{
+ bool brtn = false;
+ CFAbsoluteTime rightNow = CFAbsoluteTimeGetCurrent();
+ SessionCacheEntry **current;
+
+ for (current = &(cache->head); *current;) {
+ SessionCacheEntry *entry = *current;
+ if(SessionCacheEntryIsStale(entry, rightNow)) {
+ #ifndef DEBUG
+ sslLogSessCacheDebug("...SessionCacheCleanup: deleting "
+ "cached session (%p)", entry);
+ cachePrint(entry, &entry->mKey, &entry->mSessionData);
+ #endif
+ *current = entry->next;
+ SessionCacheEntryDelete(entry);
+ }
+ else {
+ current = &((*current)->next);
+ /* we're leaving one in the map */
+ brtn = true;
+ }
+ }
+ return brtn;
+}
+
+#if DUMP_ALL_CACHE
+static void dumpAllCache(void)
+{
+ SessionCache *cache = gSessionCache;
+ SessionCacheEntry *entry;
+
+ printf("Contents of sessionCache:\n");
+ for(entry = cache->head; entry; entry = entry->next) {
+ cachePrint(entry, &entry->mKey, &entry->mSessionData);
+ }
+}
+#endif /* DUMP_ALL_CACHE */
+
+/*
+ * Store opaque sessionData, associated with opaque sessionKey.
+ */
+OSStatus sslAddSession (
+ const SSLBuffer sessionKey,
+ const SSLBuffer sessionData,
+ uint32_t timeToLive) /* optional time-to-live in seconds; 0 ==> default */
+{
+ SessionCache *cache = SessionCacheGetLockedInstance();
+ OSStatus serr;
+ if (!cache)
+ serr = errSSLSessionNotFound;
+ else
+ {
+ serr = SessionCacheAddEntry(cache, &sessionKey, &sessionData, timeToLive);
+
+ dumpAllCache();
+ }
+
+ pthread_mutex_unlock(&gSessionCacheLock);
+ return serr;
+}
+
+/*
+ * Given an opaque sessionKey, alloc & retrieve associated sessionData.
+ */
+OSStatus sslCopySession (
+ const SSLBuffer sessionKey,
+ SSLBuffer *sessionData)
+{
+ SessionCache *cache = SessionCacheGetLockedInstance();
+ OSStatus serr;
+ if (!cache)
+ serr = errSSLSessionNotFound;
+ else
+ {
+ serr = SessionCacheLookupEntry(cache, &sessionKey, sessionData);
+
+ sslLogSessCacheDebug("sslGetSession(%d, %p): %d",
+ (int)sessionKey.length, sessionKey.data,
+ (int)serr);
+ if(!serr) {
+ cachePrint(NULL, &sessionKey, sessionData);
+ }
+ else {
+ cachePrint(NULL, &sessionKey, NULL);
+ }
+ dumpAllCache();
+ }
+
+ pthread_mutex_unlock(&gSessionCacheLock);
+
+ return serr;
+}
+
+OSStatus sslDeleteSession (
+ const SSLBuffer sessionKey)
+{
+ SessionCache *cache = SessionCacheGetLockedInstance();
+ OSStatus serr;
+ if (!cache)
+ serr = errSSLSessionNotFound;
+ else
+ {
+ serr = SessionCacheDeleteEntry(cache, &sessionKey);
+ }
+
+ pthread_mutex_unlock(&gSessionCacheLock);
+ return serr;
+}
+
+/* cleanup up session cache, deleting stale entries. */
+OSStatus sslCleanupSession(void)
+{
+ SessionCache *cache = SessionCacheGetLockedInstance();
+ OSStatus serr = errSecSuccess;
+ bool moreToGo = false;
+
+ if (!cache)
+ serr = errSSLSessionNotFound;
+ else
+ {
+ moreToGo = SessionCacheCleanup(cache);
+ }
+ /* Possible TBD: if moreToGo, schedule a timed callback to this function */
+
+ pthread_mutex_unlock(&gSessionCacheLock);
+ return serr;
+}
projects / apple / security.git / blobdiff