Bug #4810: pppoe decoder fails when protocol identity field is only 1 byte - Suricata - Open Information Security Foundation

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Bug #4810

closed

pppoe decoder fails when protocol identity field is only 1 byte

Added by Steven Ottenhoff about 3 years ago. Updated almost 3 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Steven Ottenhoff

Target version:

7.0.0-beta1

Affected Versions:

git master

Effort:

Difficulty:

Label:

C, Needs backport to 5.0, Needs backport to 6.0, Protocol

Description

We have encountered setups where the ppp protocol field is only one byte, which is valid according to rfc2516. In this case the pppoe decoder will fail as it will always uses 2 bytes to try match the protocol identifier.

We created a fix which will check if the two bytes will conform to the hdlc address extension. If not it will assume a 1 byte protocol field. I'm not sure there won't be corner cases but it will not break with 2 bytes protocol fields.

We encountered the issue wih the pppoe decoder but probably this issue might also be relevant for the ppp decoder. The same fix could be applied (shared) there.

If I can have a developer role I can assign this ticket to myself present a merge request.

Related issues 2 (0 open — 2 closed)