fix segfault when server address is unknown

[Milek7]

No description provided.

[jcbf]

Can you just add a log entry ?

[jcbf]

Do you know under what conditions that variable is NULL ? Is it reproducible ?

I was wondering. If we don't have a ip address , SPF checking doesn't make any sense....

We should have a mechanism to prevent further processing.

[Milek7]

I was wondering. If we don't have a ip address , SPF checking doesn't make any sense....

Yes, that's why it returns SMFIS_ACCEPT. Message won't be further processed.

Do you know under what conditions that variable is NULL ? Is it reproducible ?

Milter documentation says that "NULL if the type is not supported in the current version or if the SMTP connection is made via stdin.", but I observed it when connection is closed before Postfix handles it. In postfix logs it shows as "connect from unknown[unknown]".
postfix log:

postfix/smtpd[30805]: connect from unknown[unknown]
postfix/smtpd[30805]: warning: milter unix:private/smfs: can't read SMFIC_CONNECT reply packet header: Success
postfix/smtpd[30805]: lost connection after CONNECT from unknown[unknown]
postfix/smtpd[30805]: disconnect from unknown[unknown] commands=0/0

dmesg:

smf-spf[19875]: segfault at 0 ip 0000000000402c9e sp 00007f93c7122ce0 error 4 in smf-spf[400000+5000]

disassembly near 402c9e:

  402c8b:       48 83 c1 01             add    $0x1,%rcx
  402c8f:       40 88 79 ff             mov    %dil,-0x1(%rcx)
  402c93:       40 84 ff                test   %dil,%dil
  402c96:       75 dc                   jne    402c74 <__ctype_b_loc@plt+0x1064>
  402c98:       48 89 f0                mov    %rsi,%rax
  402c9b:       c6 00 00                movb   $0x0,(%rax)
  402c9e:       0f b7 02                movzwl (%rdx),%eax
  402ca1:       66 83 f8 02             cmp    $0x2,%ax
  402ca5:       0f 84 9d 01 00 00       je     402e48 <__ctype_b_loc@plt+0x1238>
  402cab:       66 83 f8 0a             cmp    $0xa,%ax
  402caf:       0f 84 73 01 00 00       je     402e28 <__ctype_b_loc@plt+0x1218>
  402cb5:       48 83 3d 43 27 20 00    cmpq   $0x0,0x202743(%rip)        # 605400 <stderr@@GLIBC_2.2.5+0xa0>
  402cbc:       00

[jcbf]

Thanks for the feedback and for the patch.