jasper at london
Feb 14, 2010, 1:43 PM
Post #3 of 3
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Phil Pennock wrote:
On 2009-06-24 at 14:28 +0100, Jasper Wallace wrote:
This is Exim version 4.63 #1 built 20-Jan-2007 10:42:32 running on
Debian GNU/Linux 4.0.
I'm trying to set up plain and login authenticators with the username
and password being looked up in nis. nis uses salted md5 passwords (the
$1$salt$hash type), these are supported by the local crypt() functions.
This works:
exim4 -d+all -be '${if
crypteq{MYPASSWORD}{${extract{2}{:}{${lookup{jasper}nis{shadow.byname}}}}}}'
but in the authenticators when testing with -bh and this server_condition:
server_condition = \
${if
crypteq{MYPASSWORD}{${extract{2}{:}{${lookup{jasper}nis{shadow.byname}}}}} \
}
i get
14:21:34 8620 search_open: nis "shadow.byname"
14:21:34 8620 search_find: file="shadow.byname"
14:21:34 8620 key="jasper" partial=-1 affix=NULL starflags=0
14:21:34 8620 LRU list:
14:21:34 8620 internal_search_find: file="shadow.byname"
14:21:34 8620 type=nis key="jasper"
14:21:34 8620 file lookup required for jasper
14:21:34 8620 in shadow.byname
14:21:34 8620 lookup failed
So any idea why nis fails in the authenticator, but not expansion testing?
It's been a decade since I last saw NIS used, so I can only guess, but:
Permissions.
You're doing the testing as the invoking user, and I suspect that's root.
The authenticator will have dropped permissions to user "exim", or
somesuch -- on Debian I believe it's "exim4" and you don't have access
for the Exim user to the NIS shadow map.
Some quick searching shows that "yp_mkdb" takes the "-s" flag, which
sets a YP_SECURE key in the database which ypserv uses to prevent
querying the map unless the client source port is <1024.
[.Apologies for the thread necroscopy, replying to this now incase
anyone finds it in the archives]
Yes, thats exactly what the problem is. I fixed it by allowing exim to
run ypmatch via sudo with no password via adding this to /etc/sudoers:
exim ALL=NOPASSWD: /usr/bin/ypmatch
and then in the authenticators using:
server_condition = "${if and { \
{!eq{$2}{}} \
{!eq{$3}{}} \
{ or { \
{crypteq{$3}{${extract{2}{:}{${run{/usr/bin/sud
o ypmatch $2 shadow.byname}}}}} } \
{and { {eq{$2}{USERNAME}} {eq{$3}{PASSWORD}} }}
\
} \ } \
} }"
USERNAME and PASSWORD where the username and password all the clients
used until i put this in place instead.
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