[sr-dev] Bug in exported function by ser modules(segmentation fault)

[Andrei Pelinescu-Onciul]

On Oct 15, 2009 at 18:08, marius zbihlei <marius.zbihlei at 1and1.ro> wrote:

[...]
> 
> 
> Problem
> The userblacklist module has the exports for the check_user_blacklist :
> { "check_user_blacklist", (cmd_function)check_user_blacklist, 2, 
> check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
> { "check_user_blacklist", (cmd_function)check_user_blacklist, 3, 
> check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
> {"check_user_blacklist", (cmd_function)check_user_blacklist, 4, 
> check_user_blacklist_fixup, 0, REQUEST_ROUTE | FAILURE_ROUTE },
> 
> The function check_user_blacklist in userblacklist.c has the signature :
> int check_user_blacklist(struct sip_msg *msg, char* str1, char* str2, 
> char* str3, char* str4)
> 
> This is cast to a cmd_function (struct sip_msg* msg, char* str1, char* 
> str2) witch is called with 2 parameters(or casted to cmd_function3 and 
> called with 3 parameters depending of the case) in the action.c 
> do_action method. This actually leaves the rest of the pointers having 
> some random not NULL values, causing the application to crash.

Ack.

> 
> I've seen that sr doesn't use the same function for various number of 
> parameters. I've made a patch that registered for each number of 
> parameters an internal function matching the configured number
> (
>   
> int check_user_blacklist2(struct sip_msg *msg, char* str1, char* str2)
> {                                                                    
>        return check_user_list(msg, str1, str2, 0, 0, 0);            
> }   
> )
> . With this everything is ok.

Yes, please patch it.
> 
> Another solution is to define cmd_function like in kamailio (haveing 6 
> (max) numbers of char*)

No, it would be slower for the common cases (more params on the stack or
more registers wasted depending on the arch).
> 
> Any suggestions from devs is most welcome. (The problem plagues also 
> cr_route call with 5 parameters)

A quick grep showed problems only in carrierroute and userblacklist:
carrierroute:
    cr_route
    cr_prime_route
    cr_nofallback_route
userblacklist:
    check_user_blacklist
    check_user_whitelist

Thanks,
Andrei