• Bug#1101131: icecast2: DoS vector using incorrect TLS teardown

    From Nicolas Peugnet@21:1/5 to All on Sun Mar 23 16:20:01 2025
    Package: icecast2
    Version: 2.4.4-4+b1
    Severity: important
    Tags: upstream

    Dear Maintainer,

    Icecast2 in Debian is affected by this upstream issue with TLS
    connections (https://gitlab.xiph.org/xiph/icecast-server/-/issues/2355):
    When in a TLS SOURCE connection the socket is closed without TLS
    teardown Icecast will read from the socket in a tight endless loop.
    This locks up the corresponding thread.

    This has been visibly patched in upstream's VCS, in a 2.4.5 branch that
    looks like it has not been released yet: https://gitlab.xiph.org/xiph/icecast-server/-/commit/8662884447efc414e885b20b965f465d37a01fb5

    I applied this patch by simply dowloading the txt version from GitLab: https://gitlab.xiph.org/xiph/icecast-server/-/commit/8662884447efc414e885b20b965f465d37a01fb5.patch

    I am currently running a patched version of icecast2 and the problems
    seems to be fixed.

    A reliable way to reproduce the issue is to enable TLS, create a stream
    with BUTT and have at least one listener (e.g. with firefox), then click
    the stop button of BUTT. This make icecast use 100% of a CPU while
    beeing in a waiting state.

    The bug did not happen back yet with the patched version.

    Could you please add this patch to the patch series?
    --
    Nicolas Peugnet

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