[Dovecot] segfault - (imap|pop3)-login during nessus scan

[Todd Rinaldo]

On Feb 19, 2010, at 9:23 PM, Timo Sirainen wrote:

> On Fri, 2010-02-19 at 15:28 -0600, Todd Rinaldo wrote:
>> pop3-login[24451]: segfault at 000000000000000c rip 0000003c7de610a2 rsp 00007fff07116968 error 4
>> 
>> I'm having a really hard time getting a core dump
> 
> Yeah, it's difficult to get login processes to core dump. In v1.2 it's
> easier though. But there's an alternative way to get the backtrace:
> 
> First set login_process_per_connection=no. Then:
> 
> gdb -p `pidof imap-login`
> cont
> <wait for crash>
> bt full

Tim, Thanks for the feedback. In the other email you sent about re-producing with nessus, note that we're using the checkpassword system, however from strace info so far we think the error happens before any fork happens to the custon auth program.

Your suggestion for trapping with gdb worked for me! Though I had to do this in gdb first cause I kept getting sigpipe breaks:
handle SIGPIPE nostop noprint pass

This is my stack trace without debug symbols. How much would symbols help you here?

Program received signal SIGSEGV, Segmentation fault.
0x0000003c7de610a2 in krb5_is_referral_realm () from /usr/lib64/libkrb5.so.3
(gdb) bt full
#0  0x0000003c7de610a2 in krb5_is_referral_realm () from /usr/lib64/libkrb5.so.3
No symbol table info available.
#1  0x0000003c7de48ade in krb5_kt_get_entry () from /usr/lib64/libkrb5.so.3
No symbol table info available.
#2  0x0000003c7fe3871e in kssl_keytab_is_available () from /lib64/libssl.so.6
No symbol table info available.
#3  0x0000003c7fe1e345 in ssl3_choose_cipher () from /lib64/libssl.so.6
No symbol table info available.
#4  0x0000003c7fe19aeb in ssl3_get_client_hello () from /lib64/libssl.so.6
No symbol table info available.
#5  0x0000003c7fe1a465 in ssl3_accept () from /lib64/libssl.so.6
No symbol table info available.
#6  0x0000003c7fe22602 in ssl23_get_client_hello () from /lib64/libssl.so.6
No symbol table info available.
#7  0x0000003c7fe22d99 in ssl23_accept () from /lib64/libssl.so.6
No symbol table info available.
#8  0x00000000004093f9 in ssl_step ()
No symbol table info available.
#9  0x00000000004095e4 in ssl_proxy_new ()
No symbol table info available.
#10 0x00000000004073b7 in login_accept_ssl ()
No symbol table info available.
#11 0x0000000000411dc8 in io_loop_handler_run ()
No symbol table info available.
#12 0x0000000000410edd in io_loop_run ()
No symbol table info available.
#13 0x000000000040706e in main ()
No symbol table info available.