diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 1c649ca..44dc11a 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -51,7 +51,7 @@
                                 size_t session_id_len,
                                 mbedtls_ssl_cache_entry **dst)
 {
-    int ret = 1;
+    int ret = MBEDTLS_ERR_SSL_CACHE_NOT_FOUND;
 #if defined(MBEDTLS_HAVE_TIME)
     mbedtls_time_t t = mbedtls_time(NULL);
 #endif
@@ -88,7 +88,7 @@
                           size_t session_id_len,
                           mbedtls_ssl_session *session)
 {
-    int ret = 1;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *entry;
 
@@ -198,7 +198,7 @@
         /* Create new entry */
         cur = mbedtls_calloc(1, sizeof(mbedtls_ssl_cache_entry));
         if (cur == NULL) {
-            return 1;
+            return MBEDTLS_ERR_SSL_ALLOC_FAILED;
         }
 
         /* Append to the end of the linked list. */
@@ -219,12 +219,13 @@
     if (old == NULL) {
         /* This should only happen on an ill-configured cache
          * with max_entries == 0. */
-        return 1;
+        return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
     }
 #else /* MBEDTLS_HAVE_TIME */
     /* Reuse first entry in chain, but move to last place. */
     if (cache->chain == NULL) {
-        return 1;
+        /* This should never happen */
+        return MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     }
 
     old = cache->chain;
@@ -260,7 +261,7 @@
                           size_t session_id_len,
                           const mbedtls_ssl_session *session)
 {
-    int ret = 1;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *cur;
 
@@ -284,7 +285,6 @@
      * and allocate a sufficiently large buffer. */
     ret = mbedtls_ssl_session_save(session, NULL, 0, &session_serialized_len);
     if (ret != MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL) {
-        ret = 1;
         goto exit;
     }
 
@@ -304,7 +304,7 @@
     }
 
     if (session_id_len > sizeof(cur->session_id)) {
-        ret = 1;
+        ret = MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
         goto exit;
     }
     cur->session_id_len = session_id_len;
@@ -336,7 +336,7 @@
                              unsigned char const *session_id,
                              size_t session_id_len)
 {
-    int ret = MBEDTLS_ERR_ERROR_GENERIC_ERROR;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *entry;
     mbedtls_ssl_cache_entry *prev;