On 02/20/06 15:19, Klaus Darilion wrote:
Daniel-Constantin Mierla wrote:
Hello Klaus,
On 02/20/06 12:31, Klaus Darilion wrote:
Daniel-Constantin Mierla wrote:
Hello Klaus,
On 02/17/06 14:59, Klaus Darilion wrote:
Is the query SQL-injection save?
Depending of what you do and how :-). Authenticating the user should prevent bad values in From header and credentials, some character sequences are not allowed to be part of user or domain names. Using values from custom headers is quite risky, you have to use other technics to ensure a trusted value. So, I am sure that someone can get some examples of doing sql-injections even without using avp_db_query() , there are many other modules doing SQL queries using parts of SIP message, but these situations can be avoided if you know what you are doing in the script. I do not know a technique to prevent 100% SQL-injections, are you aware of?
AFAIK there are 2 ways to prevent SQL injection.
- quoting and escaping
- Do not provide the user input in the SQL query, but explicit as
parameter. This way, the DB client library prevents SQL injection.
I've checked the postgresql module, which supports both version. If "params" are defined, the safe version is used. But, when raw queries are used, there is no protection through the API, thus, checks must done before. Does this query work?
if (avp_subst("s:foo","/"//")) { sl_send_reply("403","bad syntax"); }
I am not sure I got what you want to achieve with this statement. Do you want to forbid messages which have quotes or some other "dangerous" characters in some pseudo-variables? Or you want to escape the quotes?
You can do quoting and escaping from the script, as you already mentioned, using avp_subst(). Checks for special characters like quotes or double dash can be done via avp_check().
I didn't found out how to use avp_check thus I used avp_subst.
To perform regular expression matching you have to use the 're' operation.
avp_check("$avp(s:foo)", "re/"/g");
Cheers, Daniel
regards klaus
Cheers, Daniel
regards klaus