Verified this bug on SSSD version : sssd-1.15.2-50.el7_4.7.x86_64
 
Steps followed during verification:
 
1. Get RHEL 7.4 machine and install sssd and samba. Ensure libldb version is < 1.2
 
        [root@client ~]# yum install -y sssd sssd-tools samba
        [root@client ~]# rpm -q sssd sssd-tools samba libldb
        sssd-1.15.2-50.el7.x86_64
        sssd-tools-1.15.2-50.el7.x86_64
        samba-4.6.2-8.el7.x86_64
        libldb-1.1.29-1.el7.x86_64
     
2. Configure sssd as follows:
            [root@client ~]# cat /etc/sssd/sssd.conf
            [sssd]
            config_file_version = 2
            services = nss, pam
            domains = LOCAL
     
            [domain/LOCAL]
            id_provider = local
            debug_level = 9
     
3. Start sssd service and run a user lookup.
            [root@client ~]# systemclt restart sssd
            [root@client ~]# sss_useradd localtestuser1
            [root@client ~]# id localtestuser1
            uid=1000(test) gid=1000(test) groups=1000(test)
     
4. In order to reproduce the bug, update samba and libldb to latest version provided by rhel-75 repo.
            [root@client ~]# cat /etc/yum.repos.d/rhel-75.repo
            [rhel-75]
            name=rhel-75
            baseurl=http://download.eng.pnq.redhat.com/pub/rhel/nightly/RHEL-7.5-20171108.n.0/compose/Server/x86_64/os/
            enabled=1
            gpgcheck=0
            skip_if_unavailable=1
     
            [root@server ~]# rpm -q sssd sssd-tools samba libldb
            sssd-1.15.2-50.el7.x86_64
            sssd-tools-1.15.2-50.el7.x86_64
            samba-4.7.1-1.el7.x86_64
            libldb-1.2.2-1.el7.x86_64
     
5. Restart sssd and the service should crash with segmentation fault.
     
            [root@client ~]# systemctl restart sssd
            Job for sssd.service failed because a fatal signal was delivered to the control process. See "systemctl status sssd.service" and "journalctl -xe" for details.
            [root@client ~]# /usr/sbin/sssd -i
            Segmentation fault
 
6. Upgrade SSSD to the latest z-stream version and restart sssd service.
 
        [root@client ~]# cat /etc/yum.repos.d/rhel-74z.repo
        [rhel-74z]
        name=rhel-74z
        baseurl=http://download-node-02.eng.bos.redhat.com/devel/task-repos/official/sssd/1.15.2/50.el7_4.7/x86_64/
        enabled=1
        gpgcheck=0
        skip_if_unavailable=1
 
        [root@client ~]# yum update -y samba sssd
 
        [root@client ~]# rpm -q sssd sssd-tools samba libldb
        sssd-1.15.2-50.el7_4.7.x86_64
        sssd-tools-1.15.2-50.el7_4.7.x86_64
        samba-4.6.2-8.el7.x86_64
        libldb-1.1.29-1.el7.x86_64
 
        [root@client ~]# systemclt restart sssd
 
7. Lookup a user and sssd should work without crash.
 
        [root@client ~]# id localtestuser1
        uid=1000(test) gid=1000(test) groups=1000(test)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:3379