[Dovecot] Developing new Dspam Plugin

[Steffen Kaiser]

On Fri, 30 Jun 2006, Timothy White wrote:

> On 6/28/06, Timothy White <weirdit at gmail.com> wrote:
>
>> I just realised that it may be possible to exploit the snprintf and
>> send strange commands to the server, for this reason, the user that
>> the plugin uses, should only be able to run the 2 procedure's. I have
>> no idea how to make this secure, or if it is secure or not. Any ideas?
>> (e.g. snprintf(query, 20+MAXSIGLEN, "CALL SPAM(\"%s\")", signature);
>> If someone modifies the header, as long as it's within the MAXSIGLEN
>> then they can effect the query?)
>
> Anyone got ideas/comments on this?

Dunno what you exactly mean, but when the signature is user-specified, you 
have to:

a) sanities the contents, so it cannot break out of the quotes, e.g. you 
have to quote embedded quotes and escape characters, and
b) you must ensure that strlen(signatures) < 20+MAXSIGLEN - 
strlen(pattern)

Bye,

-- 
Steffen Kaiser