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neels gerrit-no-reply at lists.osmocom.orgneels has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/24727 ) Change subject: bsc: split f_verify_encr_info() from f_cipher_mode() ...................................................................... bsc: split f_verify_encr_info() from f_cipher_mode() The verification of correct encryption information so far is part of f_cipher_mode(); put it in a separate new function f_verify_encr_info() so that it can be re-used for handover channel activation. Related: SYS#5324 Change-Id: I11602d23670f436a22b891fc744fe07e470f2b79 --- M bsc/MSC_ConnectionHandler.ttcn 1 file changed, 57 insertions(+), 30 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-ttcn3-hacks refs/changes/27/24727/1 diff --git a/bsc/MSC_ConnectionHandler.ttcn b/bsc/MSC_ConnectionHandler.ttcn index 9b6f8b1..0e79420 100644 --- a/bsc/MSC_ConnectionHandler.ttcn +++ b/bsc/MSC_ConnectionHandler.ttcn @@ -713,12 +713,63 @@ } } +function f_verify_encr_info(RSL_Message rsl) runs on MSC_ConnHdlr { + var RSL_IE_Body encr_info; + var RSL_AlgId alg_rsl; + var template octetstring expect_kc; + + /* If no encryption is enabled, then make sure there is no RSL_IE_ENCR_INFO */ + if (not ispresent(g_pars.encr)) { + if (f_rsl_find_ie(rsl, RSL_IE_ENCR_INFO, encr_info)) { + Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, "Found Encryption IE, but expected no encryption"); + } + setverdict(pass); + return; + } + + /* RSL uses a different representation of the encryption algorithm, + * so we need to convert first */ + alg_rsl := f_chipher_mode_bssmap_to_rsl(g_pars.encr.enc_alg); + + if (alg_rsl == RSL_ALG_ID_A5_4 and ispresent(g_pars.encr.enc_kc128)) { + expect_kc := g_pars.encr.enc_kc128; + } else if (alg_rsl == RSL_ALG_ID_A5_0) { + /* When A5/0 is chosen, no encryption is active, so technically, no key is needed. However, 3GPP TS + * 48.058 9.3.7 Encryption Information stays quite silent about presence or absence of a key for A5/0. + * The only thing specified is how to indicate the length of the key; the possibility that the key may + * be zero length is not explicitly mentioned. So it seems that we should always send the key along, + * even for A5/0. Still, let's also allow a zero length key for A5/0. */ + expect_kc := (g_pars.encr.enc_key, ''O); + } else { + expect_kc := g_pars.encr.enc_key; + } + log("for encryption algo ", alg_rsl, " expect kc = ", expect_kc); + + if (not f_rsl_find_ie(rsl, RSL_IE_ENCR_INFO, encr_info)) { + if (alg_rsl == RSL_ALG_ID_A5_0) { + /* For A5/0, encryption is not active. It is fine to omit the Encryption Information in this + * case. Note that the first channel may see an RSL Encryption Command with A5/0 indicated, and + * a subsequent handover may activate a new channel without any Encryption Information. */ + setverdict(pass); + return; + } + Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, + "Missing Encryption Information IE"); + return; + } + + if (not match(encr_info, tr_EncrInfo(alg_rsl, expect_kc))) { + Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, + "Unexpected Kc in Encryption Information IE"); + return; + } + setverdict(pass); +} + function f_cipher_mode(TestHdlrEncrParams enc, boolean exp_fail := false) runs on MSC_ConnHdlr { var PDU_BSSAP bssap; var RSL_Message rsl; - var RSL_AlgId alg_rsl; - var template octetstring expect_kc; if (isvalue(enc.enc_kc128)) { BSSAP.send(ts_BSSMAP_CipherModeCmdKc128(enc.enc_alg, enc.enc_key, valueof(enc.enc_kc128))); @@ -726,39 +777,14 @@ BSSAP.send(ts_BSSMAP_CipherModeCmd(enc.enc_alg, enc.enc_key)); } - /* RSL uses a different representation of the encryption algorithm, - * so we need to convert first */ - alg_rsl := f_chipher_mode_bssmap_to_rsl(enc.enc_alg); - - if (alg_rsl == RSL_ALG_ID_A5_4 and ispresent(enc.enc_kc128)) { - expect_kc := enc.enc_kc128; - } else if (alg_rsl == RSL_ALG_ID_A5_0) { - /* When A5/0 is chosen, no encryption is active, so technically, no key is needed. However, 3GPP TS - * 48.058 9.3.7 Encryption Information stays quite silent about presence or absence of a key for A5/0. - * The only thing specified is how to indicate the length of the key; the possibility that the key may - * be zero length is not explicitly mentioned. So it seems that we should always send the key along, - * even for A5/0. Still, let's also allow a zero length key for A5/0. */ - expect_kc := (enc.enc_key, ''O); - } else { - expect_kc := enc.enc_key; - } - log("for encryption algo ", alg_rsl, " expect kc = ", expect_kc); - alt { /* RSL/UE Side */ - [] RSL.receive(tr_RSL_ENCR_CMD(g_chan_nr, ?, alg_rsl, ?)) -> value rsl { + [] RSL.receive(tr_RSL_ENCR_CMD(g_chan_nr)) -> value rsl { var PDU_ML3_NW_MS l3 := dec_PDU_ML3_NW_MS(rsl.ies[3].body.l3_info.payload); log("Rx L3 from net: ", l3); - var RSL_IE_Body encr_info; - if (not f_rsl_find_ie(rsl, RSL_IE_ENCR_INFO, encr_info)) { - Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, "Missing Encryption IE in RSL ENCR CMD"); - } else { - if (not match(encr_info, tr_EncrInfo(alg_rsl, expect_kc))) { - Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, - "Unexpected Kc in Encryption IE in RSL ENCR CMD"); - } - } + f_verify_encr_info(rsl); + if (ischosen(l3.msgs.rrm.cipheringModeCommand)) { f_rsl_reply(ts_RRM_CiphModeCompl, rsl); } @@ -769,6 +795,7 @@ Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, "Unexpected Cipher Mode Complete"); } else { setverdict(pass); + var RSL_AlgId alg_rsl := f_chipher_mode_bssmap_to_rsl(g_pars.encr.enc_alg); if (oct2int(bssap.pdu.bssmap.cipherModeComplete.chosenEncryptionAlgorithm.algorithmIdentifier) != enum2int(alg_rsl)) { setverdict(fail, "Unexpected Encryption Algorithm ID in BSSMAP Cipher Mode Complete"); } -- To view, visit https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/24727 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-ttcn3-hacks Gerrit-Branch: master Gerrit-Change-Id: I11602d23670f436a22b891fc744fe07e470f2b79 Gerrit-Change-Number: 24727 Gerrit-PatchSet: 1 Gerrit-Owner: neels <nhofmeyr at sysmocom.de> Gerrit-MessageType: newchange -------------- next part -------------- An HTML attachment was scrubbed... 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