Possible bug in 3.2.7

Jeremy Allison jra at samba.org
Thu Jan 15 18:04:02 GMT 2009

On Thu, Jan 15, 2009 at 02:16:34PM +0100, Remy Zandwijk wrote:
> Developers,
> I believe there is a bug in Samba 3.2.7. Please refer to:
> 	http://marc.info/?l=samba&m=123188218612431&w=2
> 	"Calling Samba print server with an aliased DNS-name fails"
> I invested some time to investigate this problem.
> Somewhere in the process a call to the function 'is_myname_or_ipaddr' 
> from lib/util_sock.c is made. Since I am calling the server by it's DNS 
> CNAME, /* Handle possible CNAME records - convert to an IP addr. */ 
> applies.
> A call to 'print_sockaddr' is made, which calls print_sockaddr_len, which 
> calls sys_getnameinfo and finaly a call to getnameinfo is made.
> The getnameinfo system call fails with error 11, which is a system error. 
> The reason why this call fails is that the buffer which is being used to 
> store the IP-address of the CNAME is too small.
> Tracing back to the place were the buffer size is determined, we see that 
> this is done in lib/util_sock.c, line 2066 and further:
> 	print_sockaddr(name,
> 		sizeof(name),
> 		&ss);
> Since I am compiling 64-bit and 'name' is a char*, the buffer size is 
> always 8. I believe this is wrong, since an IP-address string will not 
> (most of the time) fit in 8 bytes.
> To test this, I replace 'sizeof' by 'strlen'. This resolves my problem: I 
> can connect to the server by it's CNAME and I can connect to shared 
> printers.
> However, I think 'strlen' is inappropriate too. A CNAME 'a.b.nl' is only 
> 6 bytes in length, so an IP-address will still not fit.

I know what to do here to fix this.

> Browsing through the code, I found more places were 'sizeof' is being 
> used. I did not investigate this, but I imagine this could be wrong too.

I'll check.

> Please confirm this indeed is a bug. And please CC me in replies, since I 
> am not member of the samba-technical list.

Completely correct. I'm going to log this as a "blocker" bug in the samba 
bugzilla and fix it asap.


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