Merging upstream version 1.44.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 962 insertions, 0 deletions

diff --git a/web/server/h2o/libh2o/src/ssl.c b/web/server/h2o/libh2o/src/ssl.c
new file mode 100644
index 000000000..7ac6c4c96
--- /dev/null
+++ b/web/server/h2o/libh2o/src/ssl.c
@@ -0,0 +1,962 @@
+/*
+ * Copyright (c) 2015 DeNA Co., Ltd., Kazuho Oku
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+#include <assert.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <sys/stat.h>
+#include <openssl/crypto.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/rand.h>
+#include <openssl/ssl.h>
+#include "yoml-parser.h"
+#include "yrmcds.h"
+#if H2O_USE_PICOTLS
+#include "picotls.h"
+#include "picotls/openssl.h"
+#endif
+#include "h2o/file.h"
+#include "h2o.h"
+#include "h2o/configurator.h"
+#include "standalone.h"
+
+struct st_session_ticket_generating_updater_conf_t {
+    const EVP_CIPHER *cipher;
+    const EVP_MD *md;
+};
+
+struct st_session_ticket_file_updater_conf_t {
+    const char *filename;
+};
+
+static struct {
+    struct {
+        void (*setup)(SSL_CTX **contexts, size_t num_contexts);
+        union {
+            struct {
+                size_t num_threads;
+                char *prefix;
+            } memcached;
+        } vars;
+    } cache;
+    struct {
+        void *(*update_thread)(void *conf);
+        union {
+            struct st_session_ticket_generating_updater_conf_t generating;
+            struct {
+                struct st_session_ticket_generating_updater_conf_t generating; /* at same address as conf.ticket.vars.generating */
+                h2o_iovec_t key;
+            } memcached;
+            struct st_session_ticket_file_updater_conf_t file;
+        } vars;
+    } ticket;
+    unsigned lifetime;
+    struct {
+        char *host;
+        uint16_t port;
+        int text_protocol;
+    } memcached;
+} conf;
+
+H2O_NORETURN static void *cache_cleanup_thread(void *_contexts)
+{
+    SSL_CTX **contexts = _contexts;
+
+    while (1) {
+        size_t i;
+        for (i = 0; contexts[i] != NULL; ++i)
+            SSL_CTX_flush_sessions(contexts[i], time(NULL));
+        sleep(conf.lifetime / 4);
+    }
+}
+
+static void spawn_cache_cleanup_thread(SSL_CTX **_contexts, size_t num_contexts)
+{
+    /* copy the list of contexts */
+    SSL_CTX **contexts = malloc(sizeof(*contexts) * (num_contexts + 1));
+    h2o_memcpy(contexts, _contexts, sizeof(*contexts) * num_contexts);
+    contexts[num_contexts] = NULL;
+
+    /* launch the thread */
+    pthread_t tid;
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, 1);
+    h2o_multithread_create_thread(&tid, &attr, cache_cleanup_thread, contexts);
+}
+
+static void setup_cache_disable(SSL_CTX **contexts, size_t num_contexts)
+{
+    size_t i;
+    for (i = 0; i != num_contexts; ++i)
+        SSL_CTX_set_session_cache_mode(contexts[i], SSL_SESS_CACHE_OFF);
+}
+
+static void setup_cache_internal(SSL_CTX **contexts, size_t num_contexts)
+{
+    size_t i;
+    for (i = 0; i != num_contexts; ++i) {
+        SSL_CTX_set_session_cache_mode(contexts[i], SSL_SESS_CACHE_SERVER | SSL_SESS_CACHE_NO_AUTO_CLEAR);
+        SSL_CTX_set_timeout(contexts[i], conf.lifetime);
+    }
+    spawn_cache_cleanup_thread(contexts, num_contexts);
+}
+
+static void setup_cache_memcached(SSL_CTX **contexts, size_t num_contexts)
+{
+    h2o_memcached_context_t *memc_ctx =
+        h2o_memcached_create_context(conf.memcached.host, conf.memcached.port, conf.memcached.text_protocol,
+                                     conf.cache.vars.memcached.num_threads, conf.cache.vars.memcached.prefix);
+    h2o_accept_setup_async_ssl_resumption(memc_ctx, conf.lifetime);
+    size_t i;
+    for (i = 0; i != num_contexts; ++i) {
+        SSL_CTX_set_session_cache_mode(contexts[i], SSL_SESS_CACHE_SERVER | SSL_SESS_CACHE_NO_AUTO_CLEAR);
+        SSL_CTX_set_timeout(contexts[i], conf.lifetime);
+        h2o_socket_ssl_async_resumption_setup_ctx(contexts[i]);
+    }
+    spawn_cache_cleanup_thread(contexts, num_contexts);
+}
+
+static void cache_init_defaults(void)
+{
+    conf.cache.setup = setup_cache_internal;
+}
+
+#if H2O_USE_SESSION_TICKETS
+
+struct st_session_ticket_t {
+    unsigned char name[16];
+    struct {
+        const EVP_CIPHER *cipher;
+        unsigned char *key;
+    } cipher;
+    struct {
+        const EVP_MD *md;
+        unsigned char *key;
+    } hmac;
+    uint64_t not_before;
+    uint64_t not_after;
+};
+
+typedef H2O_VECTOR(struct st_session_ticket_t *) session_ticket_vector_t;
+
+static struct {
+    pthread_rwlock_t rwlock;
+    session_ticket_vector_t tickets; /* sorted from newer to older */
+} session_tickets = {
+/* we need writer-preferred lock, but on linux PTHREAD_RWLOCK_INITIALIZER is reader-preferred */
+#ifdef PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP
+    PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP
+#else
+    PTHREAD_RWLOCK_INITIALIZER
+#endif
+    ,
+    {NULL} /* tickets */
+};
+
+static struct st_session_ticket_t *new_ticket(const EVP_CIPHER *cipher, const EVP_MD *md, uint64_t not_before, uint64_t not_after,
+                                              int fill_in)
+{
+    int key_len = EVP_CIPHER_key_length(cipher), block_size = EVP_MD_block_size(md);
+    struct st_session_ticket_t *ticket = h2o_mem_alloc(sizeof(*ticket) + key_len + block_size);
+
+    ticket->cipher.cipher = cipher;
+    ticket->cipher.key = (unsigned char *)ticket + sizeof(*ticket);
+    ticket->hmac.md = md;
+    ticket->hmac.key = ticket->cipher.key + key_len;
+    ticket->not_before = not_before;
+    ticket->not_after = not_after;
+    if (fill_in) {
+        RAND_bytes(ticket->name, sizeof(ticket->name));
+        RAND_bytes(ticket->cipher.key, key_len);
+        RAND_bytes(ticket->hmac.key, block_size);
+    }
+
+    return ticket;
+}
+
+static void free_ticket(struct st_session_ticket_t *ticket)
+{
+    int key_len = EVP_CIPHER_key_length(ticket->cipher.cipher), block_size = EVP_MD_block_size(ticket->hmac.md);
+    h2o_mem_set_secure(ticket, 0, sizeof(*ticket) + key_len + block_size);
+    free(ticket);
+}
+
+static int ticket_sort_compare(const void *_x, const void *_y)
+{
+    struct st_session_ticket_t *x = *(void **)_x, *y = *(void **)_y;
+
+    if (x->not_before != y->not_before)
+        return x->not_before > y->not_before ? -1 : 1;
+    return memcmp(x->name, y->name, sizeof(x->name));
+}
+
+static void free_tickets(session_ticket_vector_t *tickets)
+{
+    size_t i;
+    for (i = 0; i != tickets->size; ++i)
+        free_ticket(tickets->entries[i]);
+    free(tickets->entries);
+    memset(tickets, 0, sizeof(*tickets));
+}
+
+static struct st_session_ticket_t *find_ticket_for_encryption(session_ticket_vector_t *tickets, uint64_t now)
+{
+    size_t i;
+
+    for (i = 0; i != tickets->size; ++i) {
+        struct st_session_ticket_t *ticket = tickets->entries[i];
+        if (ticket->not_before <= now) {
+            if (now <= ticket->not_after) {
+                return ticket;
+            } else {
+                return NULL;
+            }
+        }
+    }
+    return NULL;
+}
+
+static int ticket_key_callback(unsigned char *key_name, unsigned char *iv, EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc)
+{
+    int ret;
+    pthread_rwlock_rdlock(&session_tickets.rwlock);
+
+    if (enc) {
+        RAND_bytes(iv, EVP_MAX_IV_LENGTH);
+        struct st_session_ticket_t *ticket = find_ticket_for_encryption(&session_tickets.tickets, time(NULL)), *temp_ticket = NULL;
+        if (ticket != NULL) {
+        } else {
+            /* create a dummy ticket and use (this is the only way to continue the handshake; contrary to the man pages, OpenSSL
+             * crashes if we return zero */
+            ticket = temp_ticket = new_ticket(EVP_aes_256_cbc(), EVP_sha256(), 0, UINT64_MAX, 1);
+        }
+        memcpy(key_name, ticket->name, sizeof(ticket->name));
+        EVP_EncryptInit_ex(ctx, ticket->cipher.cipher, NULL, ticket->cipher.key, iv);
+        HMAC_Init_ex(hctx, ticket->hmac.key, EVP_MD_block_size(ticket->hmac.md), ticket->hmac.md, NULL);
+        if (temp_ticket != NULL)
+            free_ticket(ticket);
+        ret = 1;
+    } else {
+        struct st_session_ticket_t *ticket;
+        size_t i;
+        for (i = 0; i != session_tickets.tickets.size; ++i) {
+            ticket = session_tickets.tickets.entries[i];
+            if (memcmp(ticket->name, key_name, sizeof(ticket->name)) == 0)
+                goto Found;
+        }
+        /* not found */
+        ret = 0;
+        goto Exit;
+    Found:
+        EVP_DecryptInit_ex(ctx, ticket->cipher.cipher, NULL, ticket->cipher.key, iv);
+        HMAC_Init_ex(hctx, ticket->hmac.key, EVP_MD_block_size(ticket->hmac.md), ticket->hmac.md, NULL);
+        /* Request renewal if the youngest key is active */
+        if (i != 0 && session_tickets.tickets.entries[i - 1]->not_before <= time(NULL))
+            ret = 2;
+        else
+            ret = 1;
+    }
+
+Exit:
+    pthread_rwlock_unlock(&session_tickets.rwlock);
+    return ret;
+}
+
+static int ticket_key_callback_ossl(SSL *ssl, unsigned char *key_name, unsigned char *iv, EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx,
+                                    int enc)
+{
+    return ticket_key_callback(key_name, iv, ctx, hctx, enc);
+}
+
+#if H2O_USE_PICOTLS
+
+static int encrypt_ticket_key_ptls(ptls_encrypt_ticket_t *self, ptls_t *tls, int is_encrypt, ptls_buffer_t *dst, ptls_iovec_t src)
+{
+    return (is_encrypt ? ptls_openssl_encrypt_ticket : ptls_openssl_decrypt_ticket)(dst, src, ticket_key_callback);
+}
+
+#endif
+
+static int update_tickets(session_ticket_vector_t *tickets, uint64_t now)
+{
+    int altered = 0, has_valid_ticket;
+
+    /* remove old entries */
+    while (tickets->size != 0) {
+        struct st_session_ticket_t *oldest = tickets->entries[tickets->size - 1];
+        if (now <= oldest->not_after)
+            break;
+        tickets->entries[--tickets->size] = NULL;
+        free_ticket(oldest);
+        altered = 1;
+    }
+
+    /* create new entry if necessary */
+    has_valid_ticket = find_ticket_for_encryption(tickets, now) != NULL;
+    if (!has_valid_ticket || (tickets->entries[0]->not_before + conf.lifetime / 4 < now)) {
+        uint64_t not_before = has_valid_ticket ? now + 60 : now;
+        struct st_session_ticket_t *ticket = new_ticket(conf.ticket.vars.generating.cipher, conf.ticket.vars.generating.md,
+                                                        not_before, not_before + conf.lifetime - 1, 1);
+        h2o_vector_reserve(NULL, tickets, tickets->size + 1);
+        memmove(tickets->entries + 1, tickets->entries, sizeof(tickets->entries[0]) * tickets->size);
+        ++tickets->size;
+        tickets->entries[0] = ticket;
+        altered = 1;
+    }
+
+    return altered;
+}
+
+H2O_NORETURN static void *ticket_internal_updater(void *unused)
+{
+    while (1) {
+        pthread_rwlock_wrlock(&session_tickets.rwlock);
+        update_tickets(&session_tickets.tickets, time(NULL));
+        pthread_rwlock_unlock(&session_tickets.rwlock);
+        /* sleep for certain amount of time */
+        sleep(120 - (h2o_rand() >> 16) % 7);
+    }
+}
+
+static int serialize_ticket_entry(char *buf, size_t bufsz, struct st_session_ticket_t *ticket)
+{
+    char *name_buf = alloca(sizeof(ticket->name) * 2 + 1);
+    h2o_hex_encode(name_buf, ticket->name, sizeof(ticket->name));
+    int key_len = EVP_CIPHER_key_length(ticket->cipher.cipher), block_size = EVP_MD_block_size(ticket->hmac.md);
+    char *key_buf = alloca((key_len + block_size) * 2 + 1);
+    h2o_hex_encode(key_buf, ticket->cipher.key, key_len);
+    h2o_hex_encode(key_buf + key_len * 2, ticket->hmac.key, block_size);
+
+    return snprintf(buf, bufsz, "- name: %s\n"
+                                "  cipher: %s\n"
+                                "  hash: %s\n"
+                                "  key: %s\n"
+                                "  not_before: %" PRIu64 "\n"
+                                "  not_after: %" PRIu64 "\n",
+                    name_buf, OBJ_nid2sn(EVP_CIPHER_type(ticket->cipher.cipher)), OBJ_nid2sn(EVP_MD_type(ticket->hmac.md)), key_buf,
+                    ticket->not_before, ticket->not_after);
+}
+
+static struct st_session_ticket_t *parse_ticket_entry(yoml_t *element, char *errstr)
+{
+    yoml_t *t;
+    struct st_session_ticket_t *ticket;
+    unsigned char name[sizeof(ticket->name) + 1], *key;
+    const EVP_CIPHER *cipher;
+    const EVP_MD *hash;
+    uint64_t not_before, not_after;
+
+    errstr[0] = '\0';
+
+    if (element->type != YOML_TYPE_MAPPING) {
+        strcpy(errstr, "node is not a mapping");
+        return NULL;
+    }
+
+#define FETCH(n, post)                                                                                                             \
+    do {                                                                                                                           \
+        if ((t = yoml_get(element, n)) == NULL) {                                                                                  \
+            strcpy(errstr, " mandatory attribute `" n "` is missing");                                                             \
+            return NULL;                                                                                                           \
+        }                                                                                                                          \
+        if (t->type != YOML_TYPE_SCALAR) {                                                                                         \
+            strcpy(errstr, "attribute `" n "` is not a string");                                                                   \
+            return NULL;                                                                                                           \
+        }                                                                                                                          \
+        post                                                                                                                       \
+    } while (0)
+
+    FETCH("name", {
+        if (strlen(t->data.scalar) != sizeof(ticket->name) * 2) {
+            strcpy(errstr, "length of `name` attribute is not 32 bytes");
+            return NULL;
+        }
+        if (h2o_hex_decode(name, t->data.scalar, sizeof(ticket->name) * 2) != 0) {
+            strcpy(errstr, "failed to decode the hex-encoded name");
+            return NULL;
+        }
+    });
+    FETCH("cipher", {
+        if ((cipher = EVP_get_cipherbyname(t->data.scalar)) == NULL) {
+            strcpy(errstr, "cannot find the named cipher algorithm");
+            return NULL;
+        }
+    });
+    FETCH("hash", {
+        if ((hash = EVP_get_digestbyname(t->data.scalar)) == NULL) {
+            strcpy(errstr, "cannot find the named hash algorgithm");
+            return NULL;
+        }
+    });
+    FETCH("key", {
+        size_t keylen = EVP_CIPHER_key_length(cipher) + EVP_MD_block_size(hash);
+        if (strlen(t->data.scalar) != keylen * 2) {
+            sprintf(errstr, "length of the `key` attribute is incorrect (is %zu, must be %zu)\n", strlen(t->data.scalar),
+                    keylen * 2);
+            return NULL;
+        }
+        key = alloca(keylen + 1);
+        if (h2o_hex_decode(key, t->data.scalar, keylen * 2) != 0) {
+            strcpy(errstr, "failed to decode the hex-encoded key");
+            return NULL;
+        }
+    });
+    FETCH("not_before", {
+        if (sscanf(t->data.scalar, "%" SCNu64, &not_before) != 1) {
+            strcpy(errstr, "failed to parse the `not_before` attribute");
+            return NULL;
+        }
+    });
+    FETCH("not_after", {
+        if (sscanf(t->data.scalar, "%" SCNu64, &not_after) != 1) {
+            strcpy(errstr, "failed to parse the `not_after` attribute");
+            return NULL;
+        }
+    });
+    if (!(not_before <= not_after)) {
+        strcpy(errstr, "`not_after` is not equal to or greater than `not_before`");
+        return NULL;
+    }
+
+#undef FETCH
+
+    ticket = new_ticket(cipher, hash, not_before, not_after, 0);
+    memcpy(ticket->name, name, sizeof(ticket->name));
+    memcpy(ticket->cipher.key, key, EVP_CIPHER_key_length(cipher));
+    memcpy(ticket->hmac.key, key + EVP_CIPHER_key_length(cipher), EVP_MD_block_size(hash));
+    return ticket;
+}
+
+static int parse_tickets(session_ticket_vector_t *tickets, const void *src, size_t len, char *errstr)
+{
+    yaml_parser_t parser;
+    yoml_t *doc;
+    size_t i;
+
+    *tickets = (session_ticket_vector_t){NULL};
+    yaml_parser_initialize(&parser);
+
+    yaml_parser_set_input_string(&parser, src, len);
+    yoml_parse_args_t parse_args = {NULL, h2o_mem_set_secure};
+    if ((doc = yoml_parse_document(&parser, NULL, &parse_args)) == NULL) {
+        sprintf(errstr, "parse error at line %d:%s\n", (int)parser.problem_mark.line, parser.problem);
+        goto Error;
+    }
+    if (doc->type != YOML_TYPE_SEQUENCE) {
+        strcpy(errstr, "root element is not a sequence");
+        goto Error;
+    }
+    for (i = 0; i != doc->data.sequence.size; ++i) {
+        char errbuf[256];
+        struct st_session_ticket_t *ticket = parse_ticket_entry(doc->data.sequence.elements[i], errbuf);
+        if (ticket == NULL) {
+            sprintf(errstr, "at element index %zu:%s\n", i, errbuf);
+            goto Error;
+        }
+        h2o_vector_reserve(NULL, tickets, tickets->size + 1);
+        tickets->entries[tickets->size++] = ticket;
+    }
+
+    yoml_free(doc, h2o_mem_set_secure);
+    yaml_parser_delete(&parser);
+    return 0;
+Error:
+    if (doc != NULL)
+        yoml_free(doc, h2o_mem_set_secure);
+    yaml_parser_delete(&parser);
+    free_tickets(tickets);
+    return -1;
+}
+
+static h2o_iovec_t serialize_tickets(session_ticket_vector_t *tickets)
+{
+    h2o_iovec_t data = {h2o_mem_alloc(tickets->size * 1024 + 1), 0};
+    size_t i;
+
+    for (i = 0; i != tickets->size; ++i) {
+        struct st_session_ticket_t *ticket = tickets->entries[i];
+        size_t l = serialize_ticket_entry(data.base + data.len, 1024, ticket);
+        if (l > 1024) {
+            fprintf(stderr, "[src/ssl.c] %s:internal buffer overflow\n", __func__);
+            goto Error;
+        }
+        data.len += l;
+    }
+
+    return data;
+Error:
+    free(data.base);
+    return (h2o_iovec_t){NULL};
+}
+
+static int ticket_memcached_update_tickets(yrmcds *conn, h2o_iovec_t key, time_t now)
+{
+    yrmcds_response resp;
+    yrmcds_error err;
+    uint32_t serial;
+    session_ticket_vector_t tickets = {NULL};
+    h2o_iovec_t tickets_serialized = {NULL};
+    int retry = 0;
+    char errbuf[256];
+
+    /* retrieve tickets on memcached */
+    if ((err = yrmcds_get(conn, key.base, key.len, 0, &serial)) != 0) {
+        fprintf(stderr, "[lib/ssl.c] %s:yrmcds_get failed:%s\n", __func__, yrmcds_strerror(err));
+        goto Exit;
+    }
+    if ((err = yrmcds_recv(conn, &resp)) != 0) {
+        fprintf(stderr, "[lib/ssl.c] %s:yrmcds_recv failed:%s\n", __func__, yrmcds_strerror(err));
+        goto Exit;
+    }
+    if (resp.serial != serial) {
+        fprintf(stderr, "[lib/ssl.c] %s:unexpected response\n", __func__);
+        goto Exit;
+    }
+    if (resp.status == YRMCDS_STATUS_OK) {
+        int r = parse_tickets(&tickets, resp.data, resp.data_len, errbuf);
+        h2o_mem_set_secure((void *)resp.data, 0, resp.data_len);
+        if (r != 0) {
+            fprintf(stderr, "[lib/ssl.c] %s:failed to parse response:%s\n", __func__, errbuf);
+            goto Exit;
+        }
+    }
+    if (tickets.size > 1)
+        qsort(tickets.entries, tickets.size, sizeof(tickets.entries[0]), ticket_sort_compare);
+
+    /* if we need to update the tickets, atomically update the value in memcached, and request refetch to the caller */
+    if (update_tickets(&tickets, now) != 0) {
+        tickets_serialized = serialize_tickets(&tickets);
+        if (resp.status == YRMCDS_STATUS_NOTFOUND) {
+            if ((err = yrmcds_add(conn, key.base, key.len, tickets_serialized.base, tickets_serialized.len, 0, conf.lifetime, 0, 0,
+                                  &serial)) != 0) {
+                fprintf(stderr, "[lib/ssl.c] %s:yrmcds_add failed:%s\n", __func__, yrmcds_strerror(err));
+                goto Exit;
+            }
+        } else {
+            if ((err = yrmcds_set(conn, key.base, key.len, tickets_serialized.base, tickets_serialized.len, 0, conf.lifetime,
+                                  resp.cas_unique, 0, &serial)) != 0) {
+                fprintf(stderr, "[lib/ssl.c] %s:yrmcds_set failed:%s\n", __func__, yrmcds_strerror(err));
+                goto Exit;
+            }
+        }
+        if ((err = yrmcds_recv(conn, &resp)) != 0) {
+            fprintf(stderr, "[lib/ssl.c] %s:yrmcds_recv failed:%s\n", __func__, yrmcds_strerror(err));
+            goto Exit;
+        }
+        retry = 1;
+        goto Exit;
+    }
+
+    /* store the results */
+    pthread_rwlock_wrlock(&session_tickets.rwlock);
+    h2o_mem_swap(&session_tickets.tickets, &tickets, sizeof(tickets));
+    pthread_rwlock_unlock(&session_tickets.rwlock);
+
+Exit:
+    free(tickets_serialized.base);
+    free_tickets(&tickets);
+    return retry;
+}
+
+H2O_NORETURN static void *ticket_memcached_updater(void *unused)
+{
+    while (1) {
+        /* connect */
+        yrmcds conn;
+        yrmcds_error err;
+        size_t failcnt;
+        for (failcnt = 0; (err = yrmcds_connect(&conn, conf.memcached.host, conf.memcached.port)) != YRMCDS_OK; ++failcnt) {
+            if (failcnt == 0)
+                fprintf(stderr, "[src/ssl.c] failed to connect to memcached at %s:%" PRIu16 ", %s\n", conf.memcached.host,
+                        conf.memcached.port, yrmcds_strerror(err));
+            sleep(10);
+        }
+        if (conf.memcached.text_protocol)
+            yrmcds_text_mode(&conn);
+        /* connected */
+        while (ticket_memcached_update_tickets(&conn, conf.ticket.vars.memcached.key, time(NULL)))
+            ;
+        /* disconnect */
+        yrmcds_close(&conn);
+        sleep(60);
+    }
+}
+
+static int load_tickets_file(const char *fn)
+{
+#define ERR_PREFIX "failed to load session ticket secrets from file:%s:"
+
+    h2o_iovec_t data = {NULL};
+    session_ticket_vector_t tickets = {NULL};
+    char errbuf[256];
+    int ret = -1;
+
+    /* load yaml */
+    data = h2o_file_read(fn);
+    if (data.base == NULL) {
+        char errbuf[256];
+        strerror_r(errno, errbuf, sizeof(errbuf));
+        fprintf(stderr, ERR_PREFIX "%s\n", fn, errbuf);
+        goto Exit;
+    }
+    /* parse the data */
+    if (parse_tickets(&tickets, data.base, data.len, errbuf) != 0) {
+        fprintf(stderr, ERR_PREFIX "%s\n", fn, errbuf);
+        goto Exit;
+    }
+    /* sort the ticket entries being read */
+    if (tickets.size > 1)
+        qsort(tickets.entries, tickets.size, sizeof(tickets.entries[0]), ticket_sort_compare);
+    /* replace the ticket list */
+    pthread_rwlock_wrlock(&session_tickets.rwlock);
+    h2o_mem_swap(&session_tickets.tickets, &tickets, sizeof(tickets));
+    pthread_rwlock_unlock(&session_tickets.rwlock);
+
+    ret = 0;
+Exit:
+    free(data.base);
+    free_tickets(&tickets);
+    return ret;
+
+#undef ERR_PREFIX
+}
+
+H2O_NORETURN static void *ticket_file_updater(void *unused)
+{
+    time_t last_mtime = 1; /* file is loaded if mtime changes, 0 is used to indicate that the file was missing */
+
+    while (1) {
+        struct stat st;
+        if (stat(conf.ticket.vars.file.filename, &st) != 0) {
+            if (last_mtime != 0) {
+                char errbuf[256];
+                strerror_r(errno, errbuf, sizeof(errbuf));
+                fprintf(stderr, "cannot load session ticket secrets from file:%s:%s\n", conf.ticket.vars.file.filename, errbuf);
+            }
+            last_mtime = 0;
+        } else if (last_mtime != st.st_mtime) {
+            /* (re)load */
+            last_mtime = st.st_mtime;
+            if (load_tickets_file(conf.ticket.vars.file.filename) == 0)
+                fprintf(stderr, "session ticket secrets have been (re)loaded\n");
+        }
+        sleep(10);
+    }
+}
+
+static void ticket_init_defaults(void)
+{
+    conf.ticket.update_thread = ticket_internal_updater;
+    /* to protect the secret >>>2030 we need AES-256 (http://www.keylength.com/en/4/) */
+    conf.ticket.vars.generating.cipher = EVP_aes_256_cbc();
+    /* integrity checks are only necessary at the time of handshake, and sha256 (recommended by RFC 5077) is sufficient */
+    conf.ticket.vars.generating.md = EVP_sha256();
+}
+
+#endif
+
+int ssl_session_resumption_on_config(h2o_configurator_command_t *cmd, h2o_configurator_context_t *ctx, yoml_t *node)
+{
+    enum {
+        MODE_CACHE = 1,
+        MODE_TICKET = 2,
+    };
+    int modes = -1, uses_memcached;
+    yoml_t *t;
+
+    if ((t = yoml_get(node, "mode")) == NULL) {
+        h2o_configurator_errprintf(cmd, node, "mandatory attribute `mode` is missing");
+        return -1;
+    }
+    if (t->type == YOML_TYPE_SCALAR) {
+        if (strcasecmp(t->data.scalar, "off") == 0) {
+            modes = 0;
+        } else if (strcasecmp(t->data.scalar, "all") == 0) {
+            modes = MODE_CACHE;
+#if H2O_USE_SESSION_TICKETS
+            modes |= MODE_TICKET;
+#endif
+        } else if (strcasecmp(t->data.scalar, "cache") == 0) {
+            modes = MODE_CACHE;
+        } else if (strcasecmp(t->data.scalar, "ticket") == 0) {
+            modes = MODE_TICKET;
+        }
+    }
+    if (modes == -1) {
+        h2o_configurator_errprintf(cmd, t, "value of `mode` must be one of: off | all | cache | ticket");
+        return -1;
+    }
+
+    if ((modes & MODE_CACHE) != 0) {
+        cache_init_defaults();
+        if ((t = yoml_get(node, "cache-store")) != NULL) {
+            if (t->type == YOML_TYPE_SCALAR) {
+                if (strcasecmp(t->data.scalar, "internal") == 0) {
+                    /* preserve the default */
+                    t = NULL;
+                } else if (strcasecmp(t->data.scalar, "memcached") == 0) {
+                    conf.cache.setup = setup_cache_memcached;
+                    t = NULL;
+                }
+            }
+            if (t != NULL) {
+                h2o_configurator_errprintf(cmd, t, "value of `cache-store` must be one of: internal | memcached");
+                return -1;
+            }
+        }
+        if (conf.cache.setup == setup_cache_memcached) {
+            conf.cache.vars.memcached.num_threads = 1;
+            conf.cache.vars.memcached.prefix = "h2o:ssl-session-cache:";
+            if ((t = yoml_get(node, "cache-memcached-num-threads")) != NULL) {
+                if (!(t->type == YOML_TYPE_SCALAR && sscanf(t->data.scalar, "%zu", &conf.cache.vars.memcached.num_threads) == 1 &&
+                      conf.cache.vars.memcached.num_threads != 0)) {
+                    h2o_configurator_errprintf(cmd, t, "`cache-memcached-num-threads` must be a positive number");
+                    return -1;
+                }
+            }
+            if ((t = yoml_get(node, "cache-memcached-prefix")) != NULL) {
+                if (t->type != YOML_TYPE_SCALAR) {
+                    h2o_configurator_errprintf(cmd, t, "`cache-memcached-prefix` must be a string");
+                    return -1;
+                }
+                conf.cache.vars.memcached.prefix = h2o_strdup(NULL, t->data.scalar, SIZE_MAX).base;
+            }
+        }
+    } else {
+        conf.cache.setup = setup_cache_disable;
+    }
+
+    if ((modes & MODE_TICKET) != 0) {
+#if H2O_USE_SESSION_TICKETS
+        ticket_init_defaults();
+        if ((t = yoml_get(node, "ticket-store")) != NULL) {
+            if (t->type == YOML_TYPE_SCALAR) {
+                if (strcasecmp(t->data.scalar, "internal") == 0) {
+                    /* ok, preserve the defaults */
+                    t = NULL;
+                } else if (strcasecmp(t->data.scalar, "file") == 0) {
+                    conf.ticket.update_thread = ticket_file_updater;
+                    t = NULL;
+                } else if (strcasecmp(t->data.scalar, "memcached") == 0) {
+                    conf.ticket.update_thread = ticket_memcached_updater;
+                    t = NULL;
+                }
+            }
+            if (t != NULL) {
+                h2o_configurator_errprintf(cmd, t, "value of `ticket-store` must be one of: internal | file");
+                return -1;
+            }
+        }
+        if (conf.ticket.update_thread == ticket_internal_updater || conf.ticket.update_thread == ticket_memcached_updater) {
+            /* generating updater takes two arguments: cipher, hash */
+            if ((t = yoml_get(node, "ticket-cipher")) != NULL) {
+                if (t->type != YOML_TYPE_SCALAR ||
+                    (conf.ticket.vars.generating.cipher = EVP_get_cipherbyname(t->data.scalar)) == NULL) {
+                    h2o_configurator_errprintf(cmd, t, "unknown cipher algorithm");
+                    return -1;
+                }
+            }
+            if ((t = yoml_get(node, "ticket-hash")) != NULL) {
+                if (t->type != YOML_TYPE_SCALAR ||
+                    (conf.ticket.vars.generating.md = EVP_get_digestbyname(t->data.scalar)) == NULL) {
+                    h2o_configurator_errprintf(cmd, t, "unknown hash algorithm");
+                    return -1;
+                }
+            }
+            if (conf.ticket.update_thread == ticket_memcached_updater) {
+                conf.ticket.vars.memcached.key = h2o_iovec_init(H2O_STRLIT("h2o:ssl-session-key"));
+                if ((t = yoml_get(node, "ticket-memcached-prefix")) != NULL) {
+                    if (t->type != YOML_TYPE_SCALAR) {
+                        h2o_configurator_errprintf(cmd, t, "`ticket-memcached-key` must be a string");
+                        return -1;
+                    }
+                    conf.ticket.vars.memcached.key = h2o_strdup(NULL, t->data.scalar, SIZE_MAX);
+                }
+            }
+        } else if (conf.ticket.update_thread == ticket_file_updater) {
+            /* file updater reads the contents of the file and uses it as the session ticket secret */
+            if ((t = yoml_get(node, "ticket-file")) == NULL) {
+                h2o_configurator_errprintf(cmd, node, "mandatory attribute `file` is missing");
+                return -1;
+            }
+            if (t->type != YOML_TYPE_SCALAR) {
+                h2o_configurator_errprintf(cmd, node, "`file` must be a string");
+                return -1;
+            }
+            conf.ticket.vars.file.filename = h2o_strdup(NULL, t->data.scalar, SIZE_MAX).base;
+        }
+#else
+        h2o_configurator_errprintf(
+            cmd, mode, "ticket-based session resumption cannot be used, the server is built without support for the feature");
+        return -1;
+#endif
+    } else {
+        conf.ticket.update_thread = NULL;
+    }
+
+    if ((t = yoml_get(node, "memcached")) != NULL) {
+        conf.memcached.host = NULL;
+        conf.memcached.port = 11211;
+        conf.memcached.text_protocol = 0;
+        size_t index;
+        for (index = 0; index != t->data.mapping.size; ++index) {
+            yoml_t *key = t->data.mapping.elements[index].key;
+            yoml_t *value = t->data.mapping.elements[index].value;
+            if (value == t)
+                continue;
+            if (key->type != YOML_TYPE_SCALAR) {
+                h2o_configurator_errprintf(cmd, key, "attribute must be a string");
+                return -1;
+            }
+            if (strcmp(key->data.scalar, "host") == 0) {
+                if (value->type != YOML_TYPE_SCALAR) {
+                    h2o_configurator_errprintf(cmd, value, "`host` must be a string");
+                    return -1;
+                }
+                conf.memcached.host = h2o_strdup(NULL, value->data.scalar, SIZE_MAX).base;
+            } else if (strcmp(key->data.scalar, "port") == 0) {
+                if (!(value->type == YOML_TYPE_SCALAR && sscanf(value->data.scalar, "%" SCNu16, &conf.memcached.port) == 1)) {
+                    h2o_configurator_errprintf(cmd, value, "`port` must be a number");
+                    return -1;
+                }
+            } else if (strcmp(key->data.scalar, "protocol") == 0) {
+                ssize_t sel = h2o_configurator_get_one_of(cmd, value, "BINARY,ASCII");
+                if (sel == -1)
+                    return -1;
+                conf.memcached.text_protocol = (int)sel;
+            } else {
+                h2o_configurator_errprintf(cmd, key, "unknown attribute: %s", key->data.scalar);
+                return -1;
+            }
+        }
+        if (conf.memcached.host == NULL) {
+            h2o_configurator_errprintf(cmd, t, "mandatory attribute `host` is missing");
+            return -1;
+        }
+    }
+
+    uses_memcached = conf.cache.setup == setup_cache_memcached;
+#if H2O_USE_SESSION_TICKETS
+    uses_memcached = (uses_memcached || conf.ticket.update_thread == ticket_memcached_updater);
+#endif
+    if (uses_memcached && conf.memcached.host == NULL) {
+        h2o_configurator_errprintf(cmd, node, "configuration of memcached is missing");
+        return -1;
+    }
+
+    if ((t = yoml_get(node, "lifetime")) != NULL) {
+        if (!(t->type == YOML_TYPE_SCALAR && sscanf(t->data.scalar, "%u", &conf.lifetime) == 1 && conf.lifetime != 0)) {
+            h2o_configurator_errprintf(cmd, t, "value of `lifetime` must be a positive number");
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+void ssl_setup_session_resumption(SSL_CTX **contexts, size_t num_contexts)
+{
+    if (conf.cache.setup != NULL)
+        conf.cache.setup(contexts, num_contexts);
+
+#if H2O_USE_SESSION_TICKETS
+    if (num_contexts == 0)
+        return;
+
+    if (conf.ticket.update_thread != NULL) {
+        /* start session ticket updater thread */
+        pthread_t tid;
+        pthread_attr_t attr;
+        pthread_attr_init(&attr);
+        pthread_attr_setdetachstate(&attr, 1);
+        h2o_multithread_create_thread(&tid, &attr, conf.ticket.update_thread, NULL);
+        size_t i;
+        for (i = 0; i != num_contexts; ++i) {
+            SSL_CTX *ctx = contexts[i];
+            SSL_CTX_set_tlsext_ticket_key_cb(ctx, ticket_key_callback_ossl);
+#if H2O_USE_PICOTLS
+            ptls_context_t *pctx = h2o_socket_ssl_get_picotls_context(ctx);
+            if (pctx != NULL) {
+                static ptls_encrypt_ticket_t encryptor = {encrypt_ticket_key_ptls};
+                pctx->ticket_lifetime = 86400 * 7; // FIXME conf.lifetime;
+                pctx->encrypt_ticket = &encryptor;
+            }
+#endif
+        }
+    } else {
+        size_t i;
+        for (i = 0; i != num_contexts; ++i)
+            SSL_CTX_set_options(contexts[i], SSL_CTX_get_options(contexts[i]) | SSL_OP_NO_TICKET);
+    }
+#endif
+}
+
+static pthread_mutex_t *mutexes;
+
+static void lock_callback(int mode, int n, const char *file, int line)
+{
+    if ((mode & CRYPTO_LOCK) != 0) {
+        pthread_mutex_lock(mutexes + n);
+    } else if ((mode & CRYPTO_UNLOCK) != 0) {
+        pthread_mutex_unlock(mutexes + n);
+    } else {
+        assert(!"unexpected mode");
+    }
+}
+
+static unsigned long thread_id_callback(void)
+{
+    return (unsigned long)pthread_self();
+}
+
+static int add_lock_callback(int *num, int amount, int type, const char *file, int line)
+{
+    (void)type;
+    (void)file;
+    (void)line;
+
+    return __sync_add_and_fetch(num, amount);
+}
+
+void init_openssl(void)
+{
+    int nlocks = CRYPTO_num_locks(), i;
+    mutexes = h2o_mem_alloc(sizeof(*mutexes) * nlocks);
+    for (i = 0; i != nlocks; ++i)
+        pthread_mutex_init(mutexes + i, NULL);
+    CRYPTO_set_locking_callback(lock_callback);
+    CRYPTO_set_id_callback(thread_id_callback);
+    CRYPTO_set_add_lock_callback(add_lock_callback);
+
+    /* Dynamic locks are only used by the CHIL engine at this time */
+
+    SSL_load_error_strings();
+    SSL_library_init();
+    OpenSSL_add_all_algorithms();
+
+    cache_init_defaults();
+#if H2O_USE_SESSION_TICKETS
+    ticket_init_defaults();
+#endif
+    conf.lifetime = 3600; /* default value for session timeout is 1 hour */
+}