Comment 10 for bug 1578576

running an Apache2 server with NTLM authentication against an AD, stopped working with 500 Internal Server error since the Samba upgrade.

Apache config:
AuthType NTLM
AuthName "..."
NTLMAuth on
NTLMAuthHelper "/usr/bin/ntlm_auth --helper-protocol=squid-.5-ntlmssp"
NTLMBasicAuthoritative on
require valid-user

Syslog:
May 9 08:41:17 intranet-gvp kernel: [438844.377831] ntlm_auth[23011]: segfault at 8 ip 00007f512efcf9b0 sp 00007ffc8017cc78 error 4 in libsamba-security.so.0[7f512efc4000+1b000]
May 9 08:41:23 intranet-gvp kernel: [438849.956323] ntlm_auth[23148]: segfault at 8 ip 00007f39b08e99b0 sp 00007fff4ba86bb8 error 4 in libsamba-security.so.0[7f39b08de000+1b000]
May 9 08:41:30 intranet-gvp kernel: [438856.430960] ntlm_auth[23240]: segfault at 8 ip 00007f96a55309b0 sp 00007ffe0a7eaa98 error 4 in libsamba-security.so.0[7f96a5525000+1b000]
May 9 08:43:30 intranet-gvp kernel: [438977.462065] ntlm_auth[25264]: segfault at 8 ip 00007f874faf29b0 sp 00007ffd417d0478 error 4 in libsamba-security.so.0[7f874fae7000+1b000]
May 9 08:45:03 intranet-gvp kernel: [439070.043363] ntlm_auth[28559]: segfault at 8 ip 00007fb5af4769b0 sp 00007ffcc2b84918 error 4 in libsamba-security.so.0[7fb5af46b000+1b000]
May 9 08:47:12 intranet-gvp kernel: [439199.384723] ntlm_auth[30675]: segfault at 8 ip 00007f357d1439b0 sp 00007ffef1ea7c98 error 4 in libsamba-security.so.0[7f357d138000+1b000]
May 9 08:47:25 intranet-gvp kernel: [439211.944010] ntlm_auth[30822]: segfault at 8 ip 00007f89a24e49b0 sp 00007ffffb32b3c8 error 4 in libsamba-security.so.0[7f89a24d9000+1b000]
May 9 08:50:12 intranet-gvp kernel: [439379.146404] ntlm_auth[1121]: segfault at 8 ip 00007fdb6f7d19b0 sp 00007ffcf44e5728 error 4 in libsamba-security.so.0[7fdb6f7c6000+1b000]

After rollback to Samba packages 4.3.8, the system is running again.

$ pgrep ntlm -a
2192 ntlm_auth
4951 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
4952 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
4953 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
6074 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
6503 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
6596 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
15376 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
17037 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp
17149 /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp