From 5d6d4b56dcf78f8bd919fcd455645c6c05de98ba Mon Sep 17 00:00:00 2001 From: John Thacker Date: Fri, 3 Apr 2026 13:33:52 +0000 Subject: [PATCH] iLBC codec: Report proper decoded length in multiframe case Per RFC 3952, multiple iLBC frames can may be included in a single RTP packet.[1] (Note the error there about octets per frame in the 20 ms case, contradicting sections 2 and 3.1; errata has been submitted.) The output length needs to be sized to accommodate the full length, as the iLBC library decodes all the frames. 1 - https://datatracker.ietf.org/doc/html/rfc3952#section-3.2 Fix #21145 AI-Assisted: no (cherry picked from commit 7a284824c92fecc6c57d770317919388c33983ac) Co-authored-by: John Thacker --- plugins/codecs/iLBC/iLBCdecode.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) Index: wireshark-3.6.24/plugins/codecs/iLBC/iLBCdecode.c =================================================================== --- wireshark-3.6.24.orig/plugins/codecs/iLBC/iLBCdecode.c +++ wireshark-3.6.24/plugins/codecs/iLBC/iLBCdecode.c @@ -1,6 +1,8 @@ /* iLBCdecode.c * iLBC codec * + * https://datatracker.ietf.org/doc/html/rfc3952 + * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs @@ -77,16 +79,24 @@ codec_iLBC_decode(void *ctx, const void #endif int16_t *dataOut = (int16_t *)outputSamples; ilbc_ctx_t *dataCtx = (ilbc_ctx_t *)ctx; - size_t outputSamplesCount; + size_t outputSamplesCount, outputFramesCount; if (!outputSamples || !outputSamplesSize) { + /* XXX - If the payload size is a multiple of 950 (the GCM of the + * 20 ms and 30 ms payload lengths), we don't know which variant it + * is and the iLBC library doesn't seem to autodetect but uses what + * we initialize as. RFC 3952 3.2 is of no help here, suggesting + * only this algorithm. + * Do we need a codec preference? */ if (0 == inputBytesSize%ILBC_PAYLOAD_LEN_20MS) { /* 20ms packet size = 160 samples = 320 bytes */ - return BLOCKL_20MS*SAMPLE_SIZE; + outputFramesCount = inputBytesSize / ILBC_PAYLOAD_LEN_20MS; + return outputFramesCount*BLOCKL_20MS*SAMPLE_SIZE; } else if (0 == inputBytesSize%ILBC_PAYLOAD_LEN_30MS) { /* 30ms packet size = 240 samples = 480 bytes */ - return BLOCKL_30MS*SAMPLE_SIZE; + outputFramesCount = inputBytesSize / ILBC_PAYLOAD_LEN_30MS; + return outputFramesCount*BLOCKL_30MS*SAMPLE_SIZE; } else { /* unknown packet size */ return 0;