mod_ssl: Make the size of the per-dir-reneg request-body buffer

configurable, by popular demand:

* modules/ssl/ssl_private.h: Define DEFAULT_RENEG_BUFFER_SIZE.
  (SSLDirConfigRec): Add nRenegBufferSize field.

* modules/ssl/ssl_engine_config.c (ssl_cmd_SSLRenegBufferSize): New
  function.
  (ssl_config_perdir_create, ssl_config_perdir_merge): Handle
  nRenegBufferSize.

* modules/ssl/ssl_engine_io.c (ssl_io_buffer_fill): Take max buffer
  size as an argument rather than compile-time constant.

* modules/ssl/ssl_engine_kernel.c (ssl_hook_Access): Pass
  nRenegBufferSize to ssl_io_buffer_fill.

* modules/ssl/mod_ssl.c (ssl_config_cmds): Add SSLRenegBufferSize.

PR: 39243


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@726109 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 43 insertions, 12 deletions

diff --git a/modules/ssl/mod_ssl.c b/modules/ssl/mod_ssl.c
index 3fcf96508d..ee6615a31f 100644
--- a/modules/ssl/mod_ssl.c
+++ b/modules/ssl/mod_ssl.c
@@ -179,6 +179,10 @@ static const command_rec ssl_config_cmds[] = {
     SSL_CMD_DIR(Require, AUTHCFG, RAW_ARGS,
                "Require a boolean expression to evaluate to true for granting access"
                "(arbitrary complex boolean expression - see manual)")
+    SSL_CMD_DIR(RenegBufferSize, AUTHCFG, TAKE1,
+                "Configure the amount of memory that will be used for buffering the "
+                "request body if a per-location SSL renegotiation is required due to "
+                "changed access control requirements")
 
     SSL_CMD_SRV(OCSPEnable, FLAG,
                "Enable use of OCSP to verify certificate revocation (`on', `off')")
diff --git a/modules/ssl/ssl_engine_config.c b/modules/ssl/ssl_engine_config.c
index e062de8cd5..624e29befc 100644
--- a/modules/ssl/ssl_engine_config.c
+++ b/modules/ssl/ssl_engine_config.c
@@ -295,6 +295,8 @@ void *ssl_config_perdir_create(apr_pool_t *p, char *dir)
     dc->szCACertificateFile    = NULL;
     dc->szUserName             = NULL;
 
+    dc->nRenegBufferSize = DEFAULT_RENEG_BUFFER_SIZE;
+
     return dc;
 }
 
@@ -332,6 +334,8 @@ void *ssl_config_perdir_merge(apr_pool_t *p, void *basev, void *addv)
     cfgMergeString(szCACertificateFile);
     cfgMergeString(szUserName);
 
+    cfgMergeInt(nRenegBufferSize);
+
     return mrg;
 }
 
@@ -1148,6 +1152,19 @@ const char *ssl_cmd_SSLRequire(cmd_parms *cmd,
     return NULL;
 }
 
+const char *ssl_cmd_SSLRenegBufferSize(cmd_parms *cmd, void *dcfg, const char *arg)
+{
+    SSLDirConfigRec *dc = dcfg;
+    
+    dc->nRenegBufferSize = atoi(arg);
+    if (dc->nRenegBufferSize < 0) {
+        return apr_pstrcat(cmd->pool, "Invalid size for SSLRenegBufferSize: ",
+                           arg, NULL);
+    }
+
+    return NULL;
+}
+
 static const char *ssl_cmd_protocol_parse(cmd_parms *parms,
                                           const char *arg,
                                           ssl_proto_t *options)
diff --git a/modules/ssl/ssl_engine_io.c b/modules/ssl/ssl_engine_io.c
index befc53ad07..bd5ff896a2 100644
--- a/modules/ssl/ssl_engine_io.c
+++ b/modules/ssl/ssl_engine_io.c
@@ -1411,16 +1411,11 @@ static apr_status_t ssl_io_filter_output(ap_filter_t *f,
     return status;
 }
 
-/* 128K maximum buffer size by default. */
-#ifndef SSL_MAX_IO_BUFFER
-#define SSL_MAX_IO_BUFFER (128 * 1024)
-#endif
-
 struct modssl_buffer_ctx {
     apr_bucket_brigade *bb;
 };
 
-int ssl_io_buffer_fill(request_rec *r)
+int ssl_io_buffer_fill(request_rec *r, apr_size_t maxlen)
 {
     conn_rec *c = r->connection;
     struct modssl_buffer_ctx *ctx;
@@ -1437,7 +1432,8 @@ int ssl_io_buffer_fill(request_rec *r)
     /* ... and a temporary brigade. */
     tempb = apr_brigade_create(r->pool, c->bucket_alloc);
 
-    ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, "filling buffer");
+    ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, "filling buffer, max size "
+                  "%" APR_SIZE_T_FMT " bytes", maxlen);
 
     do {
         apr_status_t rv;
@@ -1493,9 +1489,10 @@ int ssl_io_buffer_fill(request_rec *r)
                       total, eos);
 
         /* Fail if this exceeds the maximum buffer size. */
-        if (total > SSL_MAX_IO_BUFFER) {
+        if (total > maxlen) {
             ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
-                          "request body exceeds maximum size for SSL buffer");
+                          "request body exceeds maximum size (%" APR_SIZE_T_FMT 
+                          ") for SSL buffer", maxlen);
             return HTTP_REQUEST_ENTITY_TOO_LARGE;
         }
 
diff --git a/modules/ssl/ssl_engine_kernel.c b/modules/ssl/ssl_engine_kernel.c
index 88b664ffff..052051f723 100644
--- a/modules/ssl/ssl_engine_kernel.c
+++ b/modules/ssl/ssl_engine_kernel.c
@@ -601,8 +601,14 @@ int ssl_hook_Access(request_rec *r)
         && !r->expecting_100) {
         int rv;
 
-        /* Fill the I/O buffer with the request body if possible. */
-        rv = ssl_io_buffer_fill(r);
+        if (dc->nRenegBufferSize > 0) {
+            /* Fill the I/O buffer with the request body if possible. */
+            rv = ssl_io_buffer_fill(r, dc->nRenegBufferSize);
+        }
+        else {
+            /* If the reneg buffer size is set to zero, just fail. */
+            rv = HTTP_REQUEST_ENTITY_TOO_LARGE;
+        }
 
         if (rv) {
             ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
diff --git a/modules/ssl/ssl_private.h b/modules/ssl/ssl_private.h
index 8c77695e1e..d8ded93750 100644
--- a/modules/ssl/ssl_private.h
+++ b/modules/ssl/ssl_private.h
@@ -139,6 +139,11 @@ ap_set_module_config(c->conn_config, &ssl_module, val)
 #define SSL_SESSION_CACHE_TIMEOUT  300
 #endif
 
+/* Default setting for per-dir reneg buffer. */
+#ifndef DEFAULT_RENEG_BUFFER_SIZE
+#define DEFAULT_RENEG_BUFFER_SIZE (128 * 1024)
+#endif
+
 /**
  * Define the per-server SSLLogLevel constants which provide
  * finer-than-debug resolution to decide if logs are to be
@@ -488,6 +493,7 @@ typedef struct {
     const char   *szCACertificatePath;
     const char   *szCACertificateFile;
     const char   *szUserName;
+    apr_size_t    nRenegBufferSize;
 } SSLDirConfigRec;
 
 /**
@@ -532,6 +538,7 @@ const char  *ssl_cmd_SSLRequireSSL(cmd_parms *, void *);
 const char  *ssl_cmd_SSLRequire(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLUserName(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLLogLevelDebugDump(cmd_parms *, void *, const char *);
+const char  *ssl_cmd_SSLRenegBufferSize(cmd_parms *cmd, void *dcfg, const char *arg);
 
 const char  *ssl_cmd_SSLProxyEngine(cmd_parms *cmd, void *dcfg, int flag);
 const char  *ssl_cmd_SSLProxyProtocol(cmd_parms *, void *, const char *);
@@ -603,7 +610,7 @@ long         ssl_io_data_cb(BIO *, int, MODSSL_BIO_CB_ARG_TYPE *, int, long, lon
 
 /* ssl_io_buffer_fill fills the setaside buffering of the HTTP request
  * to allow an SSL renegotiation to take place. */
-int          ssl_io_buffer_fill(request_rec *r);
+int          ssl_io_buffer_fill(request_rec *r, apr_size_t maxlen);
 
 /**  PRNG  */
 int          ssl_rand_seed(server_rec *, apr_pool_t *, ssl_rsctx_t, char *);