[trafficserver] 04/08: Lua plugin fix: Account for null in output from TSUrlPercentDecode.

[zw...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

zwoop pushed a commit to branch 9.0.x
in repository https://gitbox.apache.org/repos/asf/trafficserver.git

commit 92caab23add95cfe430aa0a9847e7a59674efb31
Author: Alan M. Carroll <am...@apache.org>
AuthorDate: Tue Nov 19 13:16:13 2019 -0600

    Lua plugin fix: Account for null in output from TSUrlPercentDecode.
    
    (cherry picked from commit cd2afa616239896c53cdd61c0ba94bfc1edf5d29)
---
 doc/admin-guide/plugins/lua.en.rst                 |  4 ++--
 .../api/functions/TSUrlPercentEncode.en.rst        | 24 ++++++++++++++++------
 plugins/lua/ts_lua_crypto.c                        |  4 ++--
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/doc/admin-guide/plugins/lua.en.rst b/doc/admin-guide/plugins/lua.en.rst
index 9f52692..3200f0a 100644
--- a/doc/admin-guide/plugins/lua.en.rst
+++ b/doc/admin-guide/plugins/lua.en.rst
@@ -1952,8 +1952,8 @@ ts.server_request_get_version
 
 **description:** Return the http version string of the server request.
 
-Current possible values are 1.0, 1.1, and 0.9.
-::
+Current possible values are 1.0, 1.1, and 0.9. ::
+
     function send_request()
         local version = ts.server_request.get_version()
         ts.debug(version)
diff --git a/doc/developer-guide/api/functions/TSUrlPercentEncode.en.rst b/doc/developer-guide/api/functions/TSUrlPercentEncode.en.rst
index 4e79ad4..d342368 100644
--- a/doc/developer-guide/api/functions/TSUrlPercentEncode.en.rst
+++ b/doc/developer-guide/api/functions/TSUrlPercentEncode.en.rst
@@ -51,16 +51,28 @@ failed.  :func:`TSStringPercentEncode` is similar but operates on a string. If
 the optional :arg:`map` parameter is provided (not :literal:`NULL`) , it should
 be a map of characters to encode.
 
-:func:`TSStringPercentDecode` perform percent-decoding of the string in the
-:arg:`str` buffer, writing to the :arg:`dst` buffer. The source and
-destination can be the same, in which case they overwrite. The decoded string
-is always guaranteed to be no longer than the source string.
+:func:`TSStringPercentDecode` perform percent-decoding of the string in the :arg:`str` buffer,
+writing to the :arg:`dst` buffer. The source and destination can be the same, in which case the
+decoded string is written on top of the source string. The decoded string is guaranteed to be
+no longer than the source string, but will include a terminating null which, if there are no
+escapes, makes the destination one longer than the source. In practice this means the destination
+length needs to be bumped up by one to account for the null, and a string can't be decoded in place
+if it's not already null terminated with the length of the destination including the null, but the
+length of the source *not* including the null. E.g. ::
+
+   static char const ORIGINAL[] = "A string without escapes, but null terminated";
+   char * source = TSstrdup(ORIGINAL); // make it writeable.
+   size_t length; // return value.
+   // sizeof(ORIGINAL) includes the null, so don't include that in the input.
+   static const size_t N_CHARS = sizeof(ORIGINAL) - 1;
+   TSReturnCode result = TSUrlPercentDecode(source, N_CHARS, source, N_CHARS + 1, &length);
+   ink_assert(length == N_CHARS);
 
 Return Values
 =============
 
-All these APIs returns a :type:`TSReturnCode`, indicating success
-(:data:`TS_SUCCESS`) or failure (:data:`TS_ERROR`) of the operation.
+All these APIs returns a :type:`TSReturnCode`, indicating success (:data:`TS_SUCCESS`) or failure
+(:data:`TS_ERROR`) of the operation.
 
 See Also
 ========
diff --git a/plugins/lua/ts_lua_crypto.c b/plugins/lua/ts_lua_crypto.c
index 73a79a9..7637183 100644
--- a/plugins/lua/ts_lua_crypto.c
+++ b/plugins/lua/ts_lua_crypto.c
@@ -316,8 +316,8 @@ ts_lua_unescape_uri(lua_State *L)
     return 1;
   }
 
-  /* the unescaped string can only be smaller */
-  dlen = len;
+  /* the unescaped string can not be larger, but need to account for terminating null. */
+  dlen = len + 1;
   dst  = lua_newuserdata(L, dlen);
 
   if (TS_SUCCESS == TSStringPercentDecode((const char *)src, len, (char *)dst, dlen, &length)) {