Calculate SSSD ldap_id_mapping ID from AD Domain SID. Likely full of bugs. Doesn't rely on NSS/SSSD being installed, as its a reimplementation of the generation algorithm in Python.

sss-calculate-hash.py

#!/usr/bin/python
import sys
import mmh3

# https://pagure.io/SSSD/sssd/blob/master/f/src/lib/idmap/sss_idmap_private.h
IDMAP_UPPER = 2000200000
IDMAP_LOWER = 200000
IDMAP_RANGE = 200000

max_slices = (IDMAP_UPPER - IDMAP_LOWER) / IDMAP_RANGE

if len(sys.argv) > 1:
  sid = sys.argv[1]
else:
  print("Usage: %s <SID>" % sys.argv[0])
  sys.exit(1)

print("SID         : %s" % sid)

splitsid = sid.rpartition('-')
domain = splitsid[0]
rid = int(splitsid[2])

# Generate MurmurHash3 of Domain SID
domain_hash = mmh3.hash(domain, 0xdeadbeef, signed=False)

# Generate slice
slice = domain_hash % max_slices

# Calculate offset
offset = (slice * IDMAP_RANGE) + IDMAP_LOWER

# Print some info
print("Domain Hash : %d" % domain_hash)
print("Domain Slice: %d" % slice)
print("Base offset : %d" % offset)

# Calculate and print ID
print("ID          : %d" % (offset + rid))