Re: [PATCH 0/2] ppp: mppe: fixes MPPE desync on links which don't guarantee packet ordering

From: David Miller
Date: Sun Apr 26 2015 - 23:26:39 EST

From: Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx>
Date: Sun, 26 Apr 2015 20:40:51 +0200

> I am currently having an issue with PPP over L2TP (UDP) and MPPE in
> stateless mode (default mode), UDP does not guarantee packet ordering so
> we might get out of order packet. MPPE needs to be continuously synched
> so we should drop late UDP packet.
> I added a printk on the number of time we rekeyed in MPPE decompressor,
> this is what we currently have if we receive a slightly out of order UDP
> packet:
> This is obviously wrong, we missed packet 1561 and we already rekeyed 2
> times for 1562 we previously received, we can't recover the decryption
> key we need for 1561, we should drop it instead of rekeying 4095 times.
> This patch series drop any packet with are not within the 4096/2 forward
> window.

Series applied, thanks Sylvain.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at