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Document comp-lzo no and compress being incompatible

PATCH In review Arne Schwabe 3 participants 6 messages Oct 24, 2018 – Aug 11, 2020

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Arne Schwabe

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#0 lore raw

PATCH 1/1 Document comp-lzo no and compress being incompatible

Most of the new compress but not v2 version do use swap operation. For 'compress lzo' the swap option is not used for backwards compatibility. For lz4 the swap option is also not a problem since there is no version without swap. Unfortunately, compress introduced a second stub format with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Document this weirdness to let not others fall into this trap.

---
 doc/openvpn.8 | 3 +++
 1 file changed, 3 insertions(+)
doc/openvpn.8 +3 -0
index ac923f51..f8aa94ae 100644
@@ -2551,6 +2551,9 @@ offering the best performance with least CPU usage.
 For backwards compatibility with OpenVPN versions before v2.4, use "lzo"
 (which is identical to the older option "\-\-comp\-lzo yes").
 
+Note however that the `stub` (or empty) option is NOT compatible with the
+older option "\-\-comp\-lzo no").
+
 The "lz4\-v2" and "stub\-v2" variants implement a better framing that does not add
 overhead when packets cannot be compressed. All other variants always add one extra
 framing byte compared to no compression framing.
Signature · 1 line
2.19.0
#1 lore raw
Quoted 10 lines · Arne Schwabe

Most of the new compress but not v2 version do use swap operation. For 'compress lzo' the swap option is not used for backwards compatibility. For lz4 the swap option is also not a problem since there is no version without swap. Unfortunately, compress introduced a second stub format with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Document this weirdness to let not others fall into this trap.

---
 doc/openvpn.8 | 3 +++
 1 file changed, 3 insertions(+)

This patch does not apply to git master .... which commit is this based on?

Signature · 4 lines
kind regards,

David Sommerseth
OpenVPN Inc
author
#2 lore raw

Am 26.10.18 um 13:31 schrieb David Sommerseth:

Quoted 7 lines · Arne Schwabe
Quoted 6 lines

Most of the new compress but not v2 version do use swap operation. For 'compress lzo' the swap option is not used for backwards compatibility. For lz4 the swap option is also not a problem since there is no version without swap. Unfortunately, compress introduced a second stub format with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Quoted 8 lines
Quoted 4 lines

Document this weirdness to let not others fall into this trap.

---
 doc/openvpn.8 | 3 +++
 1 file changed, 3 insertions(+)

This patch does not apply to git master .... which commit is this based on?

The allow-compression patch.

Arne

#3 lore raw

Hi,

Quoted 9 lines · Arne Schwabe

Am 26.10.18 um 13:31 schrieb David Sommerseth:

Quoted 8 lines · Arne Schwabe
Quoted 7 lines

Most of the new compress but not v2 version do use swap operation. For 'compress lzo' the swap option is not used for backwards compatibility. For lz4 the swap option is also not a problem since there is no version without swap. Unfortunately, compress introduced a second stub format with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Document this weirdness to let not others fall into this trap.

If we still want that: can you re-send based on the .rst we have no?

gert

Signature · 6 lines
"If was one thing all people took for granted, was conviction that if you 
 feed honest figures into a computer, honest figures come out. Never doubted 
 it myself till I met a computer with a sense of humor."
                             Robert A. Heinlein, The Moon is a Harsh Mistress

Gert Doering - Munich, Germany                             [email protected]...
author
#4 lore raw

PATCH v2 1/1 Document comp-lzo no and compress being incompatible

In reply to Arne Schwabe

Most of the new compress but not v2 version do use swap operation. For 'compress lzo' the swap option is not used for backwards compatibility. For lz4 the swap option is also not a problem since there is no version without swap. Unfortunately, compress introduced a second stub format with swap, contrary to the one in 'comp-lzo no' that does not use swap.

Document this weirdness to let not others fall into this trap.

Patch V2: redo patch for rst man pages

---
 doc/man-sections/protocol-options.rst | 3 +++
 1 file changed, 3 insertions(+)
doc/man-sections/protocol-options.rst +3 -0
index 240d0edf..82e4b2bd 100644
@@ -103,6 +103,9 @@ configured in a compatible way between both the local and remote side.
   ``lzo`` and ``lz4`` compression support via *IV_* variables to the
   server.
 
+  Note: the :code:`stub` (or empty) option is NOT compatible with the older
+  option ``--comp-lzo no``.
+
   ***Security Considerations***
 
   Compression and encryption is a tricky combination. If an attacker knows
Signature · 1 line
2.26.2