Segfault (null pointer) when RTMP output receives error with missing description

Operating System Info

Other

Other OS

Gentoo Linux

OBS Studio Version

32.0.4

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/9CZrOtD0zMC5ZBjg

OBS Studio Crash Log URL

No response

Expected Behavior

OBS displays an error message and fails to connect

Current Behavior

OBS segfaults

Steps to Reproduce

1. Have a misbehaving RTMP server that sends a connect _error without a description field
2. Connect OBS to it
3. Observe segfault

Specifically the message that my server sent to OBS, in response to the connect message, was:

• Message type 20 (AMF0-encoded message)
• Message body in hex: 0200065f6572726f72003ff0000000000000050000090500076d6573736167650200026869000009
• This corresponds to: the string "_error"; the transaction ID 1; an empty object; another object containing {"message":"hi"}

Anything else we should know?

At this line OBS gets the description field from the error response and passes it to the PublisherAuth function without checking whether the field was actually present:
https://github.com/obsproject/obs-studio/blob/6340d7a845ee1b7bc9b8801bed0b30f708b34c44/plugins/obs-outputs/librtmp/rtmp.c#L3290

Inside PublisherAuth the description is matched with strstr and if no description field was present, it appears description->av_val is null as it crashes inside strstr:
https://github.com/obsproject/obs-studio/blob/6340d7a845ee1b7bc9b8801bed0b30f708b34c44/plugins/obs-outputs/librtmp/rtmp.c#L2690

Start in plugins/obs-outputs/librtmp/rtmp.c at the reported lines around the RTMP error handling and PublisherAuth. Reproduce with the supplied AMF0 response or inspect the linked OBS log, then verify that an error without a description produces OBS's expected connection error rather than a segfault.