From 8f46969f8e692aa943c53f451b64a670e9622560 Mon Sep 17 00:00:00 2001
From: Graham Leggett <minfrin@apache.org>
Date: Wed, 30 Nov 2011 16:56:50 +0000
Subject: [PATCH] mod_session_crypto: Add a SessionCryptoPassphraseFile
 directive so that the administrator can hide the keys from the configuration.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1208517 13f79535-47bb-0310-9956-ffa450edef68
---
 docs/manual/mod/mod_session_crypto.xml | 30 +++++++++++++++++++++++
 modules/session/mod_session_crypto.c   | 34 ++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/docs/manual/mod/mod_session_crypto.xml b/docs/manual/mod/mod_session_crypto.xml
index 8752391961..0edfd96fea 100644
--- a/docs/manual/mod/mod_session_crypto.xml
+++ b/docs/manual/mod/mod_session_crypto.xml
@@ -163,6 +163,36 @@
 </usage>
 </directivesynopsis>
 
+<directivesynopsis>
+<name>SessionCryptoPassphraseFile</name>
+<description>File containing keys used to encrypt the session</description>
+<syntax>SessionCryptoPassphraseFile <var>filename</var></syntax>
+<default>none</default>
+<contextlist><context>server config</context>
+<context>virtual host</context>
+<context>directory</context>
+</contextlist>
+<compatibility>Available in Apache 2.3.0 and later</compatibility>
+
+<usage>
+    <p>The <directive>SessionCryptoPassphraseFile</directive> directive specifies the
+    name of a configuration file containing the keys to use for encrypting or decrypting
+    the session, specified one per line. The file is read on server start, and a graceful
+    restart will be necessary for httpd to pick up changes to the keys.</p>
+
+    <p>Unlike the <directive>SessionCryptoPassphrase</directive> directive, the keys are
+    not exposed within the httpd configuration and can be hidden by protecting the file
+    appropriately.</p>
+
+    <p>Multiple keys can be specified in order to support key rotation. The first key
+    listed will be used for encryption, while all keys listed will be attempted for
+    decryption. To rotate keys across multiple servers over a period of time, add a new
+    secret to the end of the list, and once rolled out completely to all servers, remove
+    the first key from the start of the list.</p>
+
+</usage>
+</directivesynopsis>
+
 <directivesynopsis>
 <name>SessionCryptoCipher</name>
 <description>The crypto cipher to be used to encrypt the session</description>
diff --git a/modules/session/mod_session_crypto.c b/modules/session/mod_session_crypto.c
index a85cdae6aa..f3947c910d 100644
--- a/modules/session/mod_session_crypto.c
+++ b/modules/session/mod_session_crypto.c
@@ -549,6 +549,38 @@ static const char *set_crypto_passphrase(cmd_parms * cmd, void *config, const ch
     return NULL;
 }
 
+static const char *set_crypto_passphrase_file(cmd_parms *cmd, void *config,
+                                  const char *filename)
+{
+    char buffer[MAX_STRING_LEN];
+    char *arg;
+    const char *args;
+    ap_configfile_t *file;
+    apr_status_t rv;
+
+    filename = ap_server_root_relative(cmd->temp_pool, filename);
+    rv = ap_pcfg_openfile(&file, cmd->temp_pool, filename);
+    if (rv != APR_SUCCESS) {
+        return apr_psprintf(cmd->pool, "%s: Could not open file %s: %s",
+                            cmd->cmd->name, filename,
+                            apr_strerror(rv, buffer, sizeof(buffer)));
+    }
+
+    while (!(ap_cfg_getline(buffer, sizeof(buffer), file))) {
+        args = buffer;
+        while (*(arg = ap_getword_conf(cmd->temp_pool, &args)) != '\0') {
+            if (*arg == '#' || *arg == 0) {
+                break;
+            }
+            set_crypto_passphrase(cmd, config, arg);
+        }
+    }
+
+    ap_cfg_closefile(file);
+
+    return NULL;
+}
+
 static const char *set_crypto_cipher(cmd_parms * cmd, void *config, const char *cipher)
 {
     session_crypto_dir_conf *dconf = (session_crypto_dir_conf *) config;
@@ -563,6 +595,8 @@ static const command_rec session_crypto_cmds[] =
 {
     AP_INIT_ITERATE("SessionCryptoPassphrase", set_crypto_passphrase, NULL, RSRC_CONF|OR_AUTHCFG,
             "The passphrase(s) used to encrypt the session. First will be used for encryption, all phrases will be accepted for decryption"),
+    AP_INIT_TAKE1("SessionCryptoPassphraseFile", set_crypto_passphrase_file, NULL, RSRC_CONF|ACCESS_CONF,
+            "File containing passphrase(s) used to encrypt the session, one per line. First will be used for encryption, all phrases will be accepted for decryption"),
     AP_INIT_TAKE1("SessionCryptoCipher", set_crypto_cipher, NULL, RSRC_CONF|OR_AUTHCFG,
             "The underlying crypto cipher to use"),
     AP_INIT_RAW_ARGS("SessionCryptoDriver", set_crypto_driver, NULL, RSRC_CONF,
-- 
2.40.0