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SubjectRe: [patch] af_unix fix for a panic a DoS and a memory leak [Re:
Date
Hello!

> /* Fail if the listen backlog is just full. -arca */
> if (other->ack_backlog >= other->max_ack_backlog)
> goto out;

It is wrong. As rule listen() sets backlog to low value 1-5,
and this statement will break the apps.

Unix sockets do not block in connect and have no retransmission
semantics, so that maximal number of connection can be limited
only by available system resources. Exactly as it is made
with another descriptors.

Yes, and apparently it cannot return ECONNREFUSED in this case.
Some apps uses this value to know, that server died.

Actually, there were no DoS different of normal "too may open files"
siutation", but this hack introduces new one instead:
now anyone may easily kill af_unix services by synflooding
over unix socket 8)

Alexey Kuznetsov

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