- djm@cvs.openbsd.org 2008/07/02 12:36:39
[auth2-none.c auth2.c]
Make protocol 2 MaxAuthTries behaviour a little more sensible:
Check whether client has exceeded MaxAuthTries before running
an authentication method and skip it if they have, previously it
would always allow one try (for "none" auth).
Preincrement failure count before post-auth test - previously this
checked and postincremented, also to allow one "none" try.
Together, these two changes always count the "none" auth method
which could be skipped by a malicious client (e.g. an SSH worm)
to get an extra attempt at a real auth method. They also make
MaxAuthTries=0 a useful way to block users entirely (esp. in a
sshd_config Match block).
Also, move sending of any preauth banner from "none" auth method
to the first call to input_userauth_request(), so worms that skip
the "none" method get to see it too.
diff --git a/ChangeLog b/ChangeLog
index dc80489..873e145 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -33,6 +33,22 @@
Merge duplicate host key file checks, based in part on a patch from Rob
Holland via bz #1348 . Also checks for non-regular files during protocol
1 RSA auth. ok djm@
+ - djm@cvs.openbsd.org 2008/07/02 12:36:39
+ [auth2-none.c auth2.c]
+ Make protocol 2 MaxAuthTries behaviour a little more sensible:
+ Check whether client has exceeded MaxAuthTries before running
+ an authentication method and skip it if they have, previously it
+ would always allow one try (for "none" auth).
+ Preincrement failure count before post-auth test - previously this
+ checked and postincremented, also to allow one "none" try.
+ Together, these two changes always count the "none" auth method
+ which could be skipped by a malicious client (e.g. an SSH worm)
+ to get an extra attempt at a real auth method. They also make
+ MaxAuthTries=0 a useful way to block users entirely (esp. in a
+ sshd_config Match block).
+ Also, move sending of any preauth banner from "none" auth method
+ to the first call to input_userauth_request(), so worms that skip
+ the "none" method get to see it too.
20080630
- (djm) OpenBSD CVS Sync
@@ -4516,4 +4532,4 @@
OpenServer 6 and add osr5bigcrypt support so when someone migrates
passwords between UnixWare and OpenServer they will still work. OK dtucker@
-$Id: ChangeLog,v 1.5047 2008/07/02 12:37:30 dtucker Exp $
+$Id: ChangeLog,v 1.5048 2008/07/02 12:56:09 dtucker Exp $