Possible bug in 3.2.7

Remy Zandwijk remy.zandwijk at falw.vu.nl
Thu Jan 15 13:16:34 GMT 2009


I believe there is a bug in Samba 3.2.7. Please refer to:

	"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:


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.

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.

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

Best regards,
Remy Zandwijk

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