nix-files/hosts/by-name/servo/services/export/sftpgo_external_auth_hook

158 lines
4.1 KiB
Python
Executable File

#!/usr/bin/env nix-shell
#!nix-shell -i python3 -p "python3.withPackages (ps: [ ])"
# vim: set filetype=python :
#
# available environment variables:
# - SFTPGO_AUTHD_USERNAME
# - SFTPGO_AUTHD_USER
# - SFTPGO_AUTHD_IP
# - SFTPGO_AUTHD_PROTOCOL = { "DAV", "FTP", "HTTP", "SSH" }
# - SFTPGO_AUTHD_PASSWORD
# - SFTPGO_AUTHD_PUBLIC_KEY
# - SFTPGO_AUTHD_KEYBOARD_INTERACTIVE
# - SFTPGO_AUTHD_TLS_CERT
#
# user permissions:
# - see <repo:drakkan/sftpgo:internal/dataprovider/user.go>
# - "*" = grant all permissions
# - read-only perms:
# - "list" = list files and directories
# - "download"
# - rw perms:
# - "upload"
# - "overwrite" = allow uploads to replace existing files
# - "delete" = delete files and directories
# - "delete_files"
# - "delete_dirs"
# - "rename" = rename files and directories
# - "rename_files"
# - "rename_dirs"
# - "create_dirs"
# - "create_symlinks"
# - "chmod"
# - "chown"
# - "chtimes" = change atime/mtime (access and modification times)
#
# home_dir:
# - it seems (empirically) that a user can't cd above their home directory.
# though i don't have a reference for that in the docs.
import crypt
import json
import os
from hmac import compare_digest
authFail = dict(username="")
PERM_RO = [ "list", "download" ]
PERM_RW = [
# read-only:
"list",
"download",
# write:
"upload",
"overwrite",
"delete",
"rename",
"create_dirs",
"create_symlinks",
# intentionally omitted:
# "chmod",
# "chown",
# "chtimes",
]
TRUSTED_CREDS = [
# /etc/shadow style creds.
# mkpasswd -m sha-512
# $<method>$<salt>$<hash>
"$6$Zq3c2u4ghUH4S6EP$pOuRt13sEKfX31OqPbbd1LuhS21C9MICMc94iRdTAgdAcJ9h95gQH/6Jf6Ie4Obb0oxQtojRJ1Pd/9QHOlFMW." #< m. rocket boy
]
def mkAuthOk(username: str, permissions: dict[str, list[str]]) -> dict:
return dict(
status = 1,
username = username,
expiration_date = 0,
home_dir = "/var/export",
# uid/gid 0 means to inherit sftpgo uid.
# - i.e. users can't read files which Linux user `sftpgo` can't read
# - uploaded files belong to Linux user `sftpgo`
# other uid/gid values aren't possible for localfs backend, unless i let sftpgo use `sudo`.
uid = 0,
gid = 0,
# uid = 65534,
# gid = 65534,
max_sessions = 0,
# quota_*: 0 means to not use SFTP's quota system
quota_size = 0,
quota_files = 0,
permissions = permissions,
upload_bandwidth = 0,
download_bandwidth = 0,
filters = dict(
allowed_ip = [],
denied_ip = [],
),
public_keys = [],
# other fields:
# ? groups
# ? virtual_folders
)
def isLan(ip: str) -> bool:
return ip.startswith("10.78.76.") \
or ip.startswith("10.78.77.") \
or ip.startswith("10.78.78.") \
or ip.startswith("10.78.79.")
def isWireguard(ip: str) -> bool:
return ip.startswith("10.0.10.")
def isTrustedCred(password: str) -> bool:
for cred in TRUSTED_CREDS:
_, method, salt, hash_ = cred.split("$")
# assert method == "6", f"unrecognized crypt entry: {cred}"
if crypt.crypt(password, f"${method}${salt}") == cred:
return True
return False
def getAuthResponse(ip: str, username: str, password: str) -> dict:
"""
return a sftpgo auth response either denying the user or approving them
with a set of permissions.
"""
if isTrustedCred(password) and username != "colin":
# allow r/w access from those with a special token
return mkAuthOk(username, permissions = {
"/": PERM_RW,
"/playground": PERM_RW,
})
if isWireguard(ip):
# allow any user from wireguard
return mkAuthOk(username, permissions = {
"/": PERM_RW,
"/playground": PERM_RW,
})
if isLan(ip):
if username == "anonymous":
# allow anonymous users on the LAN
return mkAuthOk("anonymous", permissions = {
"/": PERM_RO,
"/playground": PERM_RW,
})
return authFail
def main():
ip = os.environ.get("SFTPGO_AUTHD_IP", "")
username = os.environ.get("SFTPGO_AUTHD_USERNAME", "")
password = os.environ.get("SFTPGO_AUTHD_PASSWORD", "")
resp = getAuthResponse(ip, username, password)
print(json.dumps(resp))
if __name__ == "__main__":
main()