From f6c369fb8c1b2b6a567da277f35285284b43b089 Mon Sep 17 00:00:00 2001 From: Philipp Maier Date: Tue, 16 Oct 2018 15:24:47 +0200 Subject: [PATCH] gsm0808: allow decoding of zero length speech codec lists. 3GPP_TS_48.008, 3.2.2.103 Speech Codec List states the following: "The length indicator (octet 2) is a binary number indicating the absolute length of the contents after the length indicator. The length depends on the number and type of Speech Codec Elements to be included. The minimum length of one Speech Codec Element is 1 octet and the maximum length is 3 octets. The maximum number of Speech Codec Elements within the Speech Codec List is not defined." This clearly refers only to the length of a single speech codec element but not on the overall list. So speech codec lists with length 0 are indeed permitted by the spec. - Remove the assertion that checks on zero length speech codec lists. Change-Id: I1eb1f4466b98bdd26d765b0e4cc690b5e89e9dd6 Related: OS#3657 --- src/gsm/gsm0808_utils.c | 10 ---------- tests/gsm0808/gsm0808_test.c | 23 +++++++++++++++++++++++ 2 files changed, 23 insertions(+), 10 deletions(-) diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c index 886f546a5..2348105d8 100644 --- a/src/gsm/gsm0808_utils.c +++ b/src/gsm/gsm0808_utils.c @@ -349,9 +349,6 @@ uint8_t gsm0808_enc_speech_codec_list(struct msgb *msg, OSMO_ASSERT(msg); OSMO_ASSERT(scl); - /* Empty list */ - OSMO_ASSERT(scl->len >= 1); - msgb_put_u8(msg, GSM0808_IE_SPEECH_CODEC_LIST); tlv_len = msgb_put(msg, 1); old_tail = msg->tail; @@ -384,8 +381,6 @@ int gsm0808_dec_speech_codec_list(struct gsm0808_speech_codec_list *scl, OSMO_ASSERT(scl); if (!elem) return -EINVAL; - if (len == 0) - return -EINVAL; memset(scl, 0, sizeof(*scl)); @@ -404,11 +399,6 @@ int gsm0808_dec_speech_codec_list(struct gsm0808_speech_codec_list *scl, scl->len = decoded; - /* Empty list */ - if (decoded < 1) { - return -EINVAL; - } - return (int)(elem - old_elem); } diff --git a/tests/gsm0808/gsm0808_test.c b/tests/gsm0808/gsm0808_test.c index 8cf1cf4c1..0b2794f13 100644 --- a/tests/gsm0808/gsm0808_test.c +++ b/tests/gsm0808/gsm0808_test.c @@ -695,6 +695,28 @@ static void test_gsm0808_enc_dec_speech_codec_list() msgb_free(msg); } +static void test_gsm0808_enc_dec_empty_speech_codec_list() +{ + struct gsm0808_speech_codec_list enc_scl = { + .len = 0, + }; + struct gsm0808_speech_codec_list dec_scl = {}; + struct msgb *msg; + uint8_t rc_enc; + int rc_dec; + + msg = msgb_alloc(1024, "output buffer"); + rc_enc = gsm0808_enc_speech_codec_list(msg, &enc_scl); + OSMO_ASSERT(rc_enc == 2); + + rc_dec = gsm0808_dec_speech_codec_list(&dec_scl, msg->data + 2, msg->len - 2); + OSMO_ASSERT(rc_dec == 0); + + OSMO_ASSERT(memcmp(&enc_scl, &dec_scl, sizeof(enc_scl)) == 0); + + msgb_free(msg); +} + static void test_gsm0808_enc_dec_channel_type() { struct gsm0808_channel_type enc_ct = { @@ -1725,6 +1747,7 @@ int main(int argc, char **argv) test_gsm0808_enc_dec_speech_codec_ext_with_cfg(); test_gsm0808_enc_dec_speech_codec_with_cfg(); test_gsm0808_enc_dec_speech_codec_list(); + test_gsm0808_enc_dec_empty_speech_codec_list(); test_gsm0808_enc_dec_channel_type(); test_gsm0808_enc_dec_encrypt_info();