发布日期：2013-11-27
更新日期：2013-11-28

受影响系统：

Apache Group Subversion 1.8.5
Apache Group Subversion 1.7.14

描述：

---

BUGTRAQ  ID: 63966
CVE(CAN) ID: CVE-2013-4505

Subversion是一款开源多用户版本控制系统，支持非ASCII文本和二进制数据。

Apache Subversion 1.7.14 、1.8.5之前版本的mod_dontdothat没有阻止某些serf客户端的请求，这可使客户端绕过mod_dontdothat限制并非法访问服务器资源。

<*来源：Ben Reser
  
  链接：https://bugzilla.redhat.com/show_bug.cgi?id=1033995
        http://subversion.apache.org/security/CVE-2013-4505-advisory.txt
*>

建议：

---

厂商补丁：

Apache Group
------------
Apache Group已经为此发布了一个安全公告（CVE-2013-4505-advisory）以及相应补丁:
CVE-2013-4505-advisory：mod_dontdothat does not restrict requests from serf based clients.
链接：http://subversion.apache.org/security/CVE-2013-4505-advisory.txt

补丁下载：



Patch for Subversion 1.7.x and 1.8.x:
[[[
Index: tools/server-side/mod_dontdothat/mod_dontdothat.c
===================================================================
--- tools/server-side/mod_dontdothat/mod_dontdothat.c    (revision 1541183)
+++ tools/server-side/mod_dontdothat/mod_dontdothat.c    (working copy)
@@ -30,6 +30,7 @@
#include <util_filter.h>
#include <ap_config.h>
#include <apr_strings.h>
+#include <apr_uri.h>

#include <expat.h>

@@ -36,6 +37,8 @@
#include "mod_dav_svn.h"
#include "svn_string.h"
#include "svn_config.h"
+#include "svn_path.h"
+#include "private/svn_fspath.h"

module AP_MODULE_DECLARE_DATA dontdothat_module;

@@ -161,6 +164,34 @@
     }
}

+/* duplicate of dav_svn__log_err() from mod_dav_svn/util.c */
+static void
+log_dav_err(request_rec *r,
+            dav_error *err,
+            int level)
+{
+    dav_error *errscan;
+
+    /* Log the errors */
+    /* ### should have a directive to log the first or all */
+    for (errscan = err; errscan != NULL; errscan = errscan->prev) {
+        apr_status_t status;
+
+        if (errscan->desc == NULL)
+            continue;
+
+#if AP_MODULE_MAGIC_AT_LEAST(20091119,0)
+        status = errscan->aprerr;
+#else
+        status = errscan->save_errno;
+#endif
+
+        ap_log_rerror(APLOG_MARK, level, status, r,
+                      "%s  [%d, #%d]",
+                      errscan->desc, errscan->status, errscan->error_id);
+    }
+}
+
static svn_boolean_t
is_this_legal(dontdothat_filter_ctx *ctx, const char *uri)
{
@@ -167,20 +198,37 @@
   const char *relative_path;
   const char *cleaned_uri;
   const char *repos_name;
+  const char *uri_path;
   int trailing_slash;
   dav_error *derr;

-  /* Ok, so we need to skip past the scheme, host, etc. */
-  uri = ap_strstr_c(uri, "://");
-  if (uri)
-    uri = ap_strchr_c(uri + 3, '/');
+  /* uri can be an absolute uri or just a path, we only want the path to match
+   * against */
+  if (uri && svn_path_is_url(uri))
+    {
+      apr_uri_t parsed_uri;
+      apr_status_t rv = apr_uri_parse(ctx->r->pool, uri, &parsed_uri);
+      if (APR_SUCCESS != rv)
+        {
+          /* Error parsing the URI, log and reject request. */
+          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, ctx->r,
+                        "mod_dontdothat: blocked request after failing "
+                        "to parse uri: '%s'", uri);
+          return FALSE;
+        }
+      uri_path = parsed_uri.path;
+    }
+  else
+    {
+      uri_path = uri;
+    }

-  if (uri)
+  if (uri_path)
     {
       const char *repos_path;

       derr = dav_svn_split_uri(ctx->r,
-                               uri,
+                               uri_path,
                                ctx->cfg->base_path,
                                &cleaned_uri,
                                &trailing_slash,
@@ -194,7 +242,7 @@
           if (! repos_path)
             repos_path = "";

-          repos_path = apr_psprintf(ctx->r->pool, "/%s", repos_path);
+          repos_path = svn_fspath__canonicalize(repos_path, ctx->r->pool);

           /* First check the special cases that are always legal... */
           for (idx = 0; idx < ctx->allow_recursive_ops->nelts; ++idx)
@@ -228,7 +276,20 @@
                 }
             }
         }
+      else
+        {
+          log_dav_err(ctx->r, derr, APLOG_ERR);
+          return FALSE;
+        }
+
     }
+  else
+    {
+      ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, ctx->r,
+                    "mod_dontdothat: empty uri passed to is_this_legal(), "
+                    "module bug?");
+      return FALSE;
+    }

   return TRUE;
}
]]]

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