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  1. Undertow
  2. UNDERTOW-1878

Using ^ character in query string with HTTP/2 results in protocol error being returned to client

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    • Icon: Bug Bug
    • Resolution: Won't Do
    • Icon: Major Major
    • None
    • 2.2.3.Final
    • Core
    • None
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      Any undertow instance using HTTP/2 - connect to it using a browser and request e.g. https://some.server.name/?test=^

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      Any undertow instance using HTTP/2 - connect to it using a browser and request e.g. https://some.server.name/?test= ^
    • Undefined

      When using the character ^ as part of a query string (or path) the request is rejected with a protocol errors.

      This seems to be HttpRequestParser.isTargetCharacterAllowed(char c) that uses the following table:

              for(int i = 0; i < 256; ++i) {
            if(i < 32 || i > 126) {
                ALLOWED_TARGET_CHARACTER[i] = false;
            } else {
                switch ((char)i) {
                    case '\"':
                    case '#':
                    case '<':
                    case '>':
                    case '\\':
                    case '^':
                    case '`':
                    case '{':
                    case '|':
                    case '}':
                        ALLOWED_TARGET_CHARACTER[i] = false;
                        break;
                    default:
                        ALLOWED_TARGET_CHARACTER[i] = true;
                }
            }
        }

      The problem is that some older applications uses the ^ character as part of the query string and this works perfectly will with HTTP1.1 in Undertow, but not with HTTP/2 enabled.

      I can understand that some of this was implemented to as a quick fix to guard against request smuggling but perhaps the check should not be this strict on the ":path" header ?

              rhn-cservice-bbaranow Bartosz Baranowski
              kimrastp Kim Rasmussen (Inactive)
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                Created:
                Updated:
                Resolved: