AuthInitWithoutHmacAlgo.seq - The HMAC-ALGO parameter MUST be included once in the INIT or INIT-ACK chunk
To verify that if the HMAC-ALGO parameter be omitted in the INIT or INIT-ACK chunk, The SCTP endpoint will has the no capable to receive or send authenticated chunks.
./AuthInitWithoutHmacAlgo.seq [-tooloption ...] -pkt ./AuthInitWithoutHmacAlgo.def -tooloption : v6eval tool option See Also: ../common/STD_PKT_COMMON.def ../common/SCTP_COMMON.def
Association is not established between endpoint A and B. Arrange data in endpoint A such that INIT chunk without HMAC-ALGO parameter but want to sent packet in authenticated way is sent to endpoint B.
Endpoint A Endpoint B ULP (CLOSED) (CLOSED)
INIT ------------------> (without HMAC-ALGO parameter) <------------------ INIT-ACK (with no AUTH capable) COOKIE-ECHO ------------------>
<------------------ COOKIE-ACK
DATA ------------------>
<------------------ SACK
TEST DESCRIPTION:
1. Attempt to make an association from endpoint A to B. Send INIT message containing CHUNKS Parameter and RANDOM Parameter, but without HMAC-ALGO parameter. SACK chunk be listed in the CHUNKS parameter. 2. Check A: Association is established between endpoint A and B with no AUTH capable. 3. Send DATA chunk from endpoint A to B. 4. Check B: SACK should be received at endpoint A. And is not send in authenticated way.
None
RFC 4895
6.1. Establishment of an Association Shared Key
An SCTP endpoint willing to receive or send authenticated chunks MUST send one RANDOM parameter in its INIT or INIT-ACK chunk. The RANDOM parameter MUST contain a 32-byte Random Number. The Random Number should be generated in accordance with RFC 4086 [7]. If the Random Number is not 32 bytes, the association MUST be aborted. The ABORT chunk SHOULD contain the error cause 'Protocol Violation'. In case of INIT collision, the rules governing the handling of this Random Number follow the same pattern as those for the Verification Tag, as explained in Section 5.2.4 of RFC 2960 [5]. Therefore, each endpoint knows its own Random Number and the peer's Random Number after the association has been established.
An SCTP endpoint has a list of chunks it only accepts if they are received in an authenticated way. This list is included in the INIT and INIT-ACK, and MAY be omitted if it is empty. Since this list does not change during the lifetime of the SCTP endpoint there is no problem in case of INIT collision.
Each SCTP endpoint MUST include in the INIT and INIT-ACK a HMAC-ALGO parameter containing a list of HMAC Identifiers it requests the peer to use. The receiver of an HMAC-ALGO parameter SHOULD use the first listed algorithm it supports. The HMAC algorithm based on SHA-1 MUST be supported and included in the HMAC-ALGO parameter. An SCTP endpoint MUST NOT change the parameters listed in the HMAC-ALGO parameter during the lifetime of the endpoint.
Both endpoints of an association MAY have endpoint pair shared keys that are byte vectors and pre-configured or established by another mechanism. They are identified by the Shared Key Identifier. For each endpoint pair shared key, an association shared key is computed. If there is no endpoint pair shared key, only one association shared key is computed by using an empty byte vector as the endpoint pair shared key.
The RANDOM parameter, the CHUNKS parameter, and the HMAC-ALGO parameter sent by each endpoint are concatenated as byte vectors. These parameters include the parameter type, parameter length, and the parameter value, but padding is omitted; all padding MUST be removed from this concatenation before proceeding with further computation of keys. Parameters that were not sent are simply omitted from the concatenation process. The resulting two vectors are called the two key vectors.
From the endpoint pair shared keys and the key vectors, the association shared keys are computed. This is performed by selecting the numerically smaller key vector and concatenating it to the endpoint pair shared key, and then concatenating the numerically larger key vector to that. If the key vectors are equal as numbers but differ in length, then the concatenation order is the endpoint shared key, followed by the shorter key vector, followed by the longer key vector. Otherwise, the key vectors are identical, and may be concatenated to the endpoint pair key in any order. The concatenation is performed on byte vectors, and all numerical comparisons use network byte order to convert the key vectors to a number. The result of the concatenation is the association shared key.