Description of problem:
Happened in normal system use (with postfix enabled) after the 'map' permission was introduced.
SELinux is preventing pickup from 'map' accesses on the file /var/lib/sss/mc/initgroups.

*****  Plugin catchall (100. confidence) suggests   **************************

If you believe that pickup should be allowed map access on the initgroups file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'pickup' --raw | audit2allow -M my-pickup
# semodule -X 300 -i my-pickup.pp

Additional Information:
Source Context                system_u:system_r:postfix_pickup_t:s0
Target Context                system_u:object_r:sssd_public_t:s0
Target Objects                /var/lib/sss/mc/initgroups [ file ]
Source                        pickup
Source Path                   pickup
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           sssd-common-1.15.3-2.fc27.x86_64
Policy RPM                    selinux-policy-3.13.1-270.fc27.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Permissive
Host Name                     (removed)
Platform                      Linux (removed) 4.13.0-0.rc4.git4.1.fc27.x86_64 #1
                              SMP Fri Aug 11 15:03:46 UTC 2017 x86_64 x86_64
Alert Count                   14
First Seen                    2017-08-12 17:11:23 PDT
Last Seen                     2017-08-14 21:01:38 PDT
Local ID                      26bd0eaa-3083-4dfd-a6b3-848d8e225225

Raw Audit Messages
type=AVC msg=audit(1502769698.719:677): avc:  denied  { map } for  pid=14924 comm="pickup" path="/var/lib/sss/mc/initgroups" dev="dm-2" ino=393253 scontext=system_u:system_r:postfix_pickup_t:s0 tcontext=system_u:object_r:sssd_public_t:s0 tclass=file permissive=1


Hash: pickup,postfix_pickup_t,sssd_public_t,file,map

Version-Release number of selected component:
selinux-policy-3.13.1-270.fc27.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.9.1
hashmarkername: setroubleshoot
kernel:         4.13.0-0.rc4.git4.1.fc27.x86_64
type:           libreport