[fetchmail-users] Fetchmail crash (SIGSERV)

[Voldemar <de...@it...>]

Fetchmail crash (SIGSERV)

Hello !

$ uname -a                                                                      
FreeBSD netadmin.ssmu.ru 4.11-RELEASE FreeBSD 4.11-RELEASE #3: Wed Aug 17 10:31:
07 OMSST 2005     ro...@ne...:/usr/src/sys/compile/netadmin  i386

fetchmail-6.3.2_1
Build from FreeBSD-ports (from source)

$ gcc -v                                 
Using builtin specs.                     
gcc version 2.95.4 20020320 [FreeBSD]    

$ fetchmail -V
This is fetchmail release 6.3.2+POP2+RPA+SDPS+SSL+OPIE+NLS.

$ cat .fetchmailrc
poll inet.tsu.ru    
timeout 120         
protocol pop3       
user deka           
pass ****
                    
poll pop3.mail.ru   
timeout 180         
protocol pop3       
user vega0          
pass ****
                    
poll 212.192.112.206
timeout 30          
protocol pop3       
user deka           
pass ****

$ fetchmail                                                     
fetchmail: No mail for deka at inet.tsu.ru                      
POP3 connection to pop3.mail.ru failed: Connection refused      
fetchmail: Query status=2 (SOCKET)                              
Segmentation fault                                              

$ gdb fetchmail
...[skip]...
Program received signal SIGSEGV, Segmentation fault.
0x8061c20 in xstrdup (s=0x0) at xmalloc.c:56
56          p = (char *) xmalloc(strlen(s)+1);
(gdb) backtrace
#0  0x8061c20 in xstrdup (s=0x0) at xmalloc.c:56
#1  0x805478d in do_session (ctl=0x8081600, proto=0x80642c0, maxfetch=0) at driver.c:1030
#2  0x8055573 in do_protocol (ctl=0x8081600, proto=0x80642c0) at driver.c:1630
#3  0x804bf6e in doPOP3 (ctl=0x8081600) at pop3.c:1304
#4  0x80501cd in query_host (ctl=0x8081600) at fetchmail.c:1403
#5  0x804eac4 in main (argc=1, argv=0xbfbffb10) at fetchmail.c:685

It seems to me, the function getaddrinfo returns 0 (no error),
but thus res->ai_canonname == 0, that leads SIGSERV at attempt
strcpy(0) in xmalloc.c:xstrdup.

I do not know, whether is a mistake: fetchmail or incorrect behaviour libc.
My variant of patch (not assured of its correctness,
however fetchmail starts to work normally):

$ diff driver.c ../driver.c
1030c1030,1034                                                               
<                   ctl->server.truename = xstrdup(res->ai_canonname);       
---                                                                          
>                   if (res->ai_canonname) {                                 
>                     ctl->server.truename = xstrdup(res->ai_canonname);     
>                   } else {                                                 
>                     ctl->server.truename = xstrdup(ctl->server.queryname); 
>                   };      

Excuse me, if to you already informed on this mistake. Thanks