Possible NULL dereference in celt_encode_with_ec

[a1batross]

opus_custom_encode calls celt_encode_with_ec with NULL passed as ec_enc *enc parameter.

In this function, ec_enc_shrink is called at https://github.com/xiph/opus/blob/main/celt/celt_encoder.c#L1596. enc variable gets initialized in branch below at https://github.com/xiph/opus/blob/main/celt/celt_encoder.c#L1607.

Unlike other branches that check for enc being NULL pointer, here it's omitted, causing a crash when st->bitrate isn't OPUS_BITRATE_MAX.

[a1batross]

It seems it was broken here: 9fdc489

[SNMetamorph]

I think it's worth to post this issue on their GitLab because it seems more alive.
https://gitlab.xiph.org/xiph/opus/-/issues

[a1batross]

Seems to be fixed at 5e5e7f6