PE rich signature improvements (#1135)

* rich_internal function now returns the sum of counts
of the matching rich entries instead of a boolean

It remains backwards compatible thanks to non-null values being
considered as true and when not found it returns 0 (false).

* Update documentation of the `toolid` and `version` in PE module
to reflect changes of behavior: it now returns the sum of counts matching
to given `toolid` and `version`.

* Added test for the updated rich_signature function

docs/modules/pe.rst

@@ -792,25 +792,33 @@ Reference
 
         .. versionadded:: 3.5.0
 
-        Function returning true if the PE has the specified *version* in the PE's rich
-        signature. Provide the optional *toolid* argument to only match when both match
-        for one entry. More information can be found here:
+        Function returning a sum of count values of all matching *version*
+        records. Provide the optional *toolid* argument to only match when both
+        match for one entry. More information can be found here:
 
         http://www.ntcore.com/files/richsign.htm
 
-        *Example: pe.rich_signature.version(21005)*
+        Note: Prior to version *3.11.0*, this function returns only a boolean
+        value (0 or 1) if the given *version* and optional *toolid* is present
+        in an entry.
+
+        *Example: pe.rich_signature.version(24215, 261) == 61*
 
     .. c:function:: toolid(toolid, [version])
 
         .. versionadded:: 3.5.0
 
-        Function returning true if the PE has the specified *id* in the PE's rich
-        signature. Provide the optional *version* argument to only match when both
-        match for one entry. More information can be found here:
+        Function returning a sum of count values of all matching *toolid*
+        records. Provide the optional *version* argument to only match when
+        both match for one entry. More information can be found here:
 
         http://www.ntcore.com/files/richsign.htm
 
-        *Example: pe.rich_signature.toolid(222)*
+        Note: Prior to version *3.11.0*, this function returns only a boolean
+        value (0 or 1) if the given *toolid* and optional *version* is present
+        in an entry.
+
+        *Example: pe.rich_signature.toolid(170, 40219) >= 99 and pe.rich_signature.toolid(170, 40219) <= 143*
 
 .. c:function:: exports(function_name)
 

libyara/modules/pe.c

@@ -2220,6 +2220,8 @@ static uint64_t rich_internal(
   rich_count = \
       (rich_length - sizeof(RICH_SIGNATURE)) / sizeof(RICH_VERSION_INFO);
 
+
+  uint64_t count_sum = 0;
   for (i = 0; i < rich_count; i++)
   {
     DWORD id_version = yr_le32toh(clear_rich_signature->versions[i].id_version);
@@ -2227,27 +2229,14 @@ static uint64_t rich_internal(
     int match_version = (version == RICH_VERSION_VERSION(id_version));
     int match_toolid = (toolid == RICH_VERSION_ID(id_version));
 
-    if (version != UNDEFINED && toolid != UNDEFINED)
+    if ((version == UNDEFINED || match_version) &&
+        (toolid == UNDEFINED || match_toolid))
     {
-      // check version and toolid
-      if (match_version && match_toolid)
-        return true;
-    }
-    else if (version != UNDEFINED)
-    {
-      // check only version
-      if (match_version)
-        return true;
-    }
-    else if (toolid != UNDEFINED)
-    {
-      // check only toolid
-      if (match_toolid)
-        return true;
+      count_sum += yr_le32toh(clear_rich_signature->versions[i].times);
     }
   }
 
-  return false;
+  return count_sum;
 }
 
 

tests/test-pe.c

@@ -207,6 +207,17 @@ int main(int argc, char** argv)
       }",
       "tests/data/tiny-idata-51ff");
 
+  assert_true_rule_file(
+      "import \"pe\" \
+      rule test { \
+        condition: \
+          pe.rich_signature.toolid(157, 40219) == 1 and \
+          pe.rich_signature.toolid(1, 0) > 40 and pe.rich_signature.toolid(1, 0) < 45 and \
+          pe.rich_signature.version(30319) and \
+          pe.rich_signature.version(40219, 170) == 11 \
+      }",
+      "tests/data/079a472d22290a94ebb212aa8015cdc8dd28a968c6b4d3b88acdd58ce2d3b885");
+
   yr_finalize();
   return 0;
 }