xref: /openbmc/openbmc/poky/meta/lib/oe/gpg_sign.py (revision c1d34338)
1#
2# SPDX-License-Identifier: GPL-2.0-only
3#
4
5"""Helper module for GPG signing"""
6import os
7
8import bb
9import oe.utils
10import subprocess
11import shlex
12
13class LocalSigner(object):
14    """Class for handling local (on the build host) signing"""
15    def __init__(self, d):
16        self.gpg_bin = d.getVar('GPG_BIN') or \
17                  bb.utils.which(os.getenv('PATH'), 'gpg')
18        self.gpg_cmd = [self.gpg_bin]
19        self.gpg_agent_bin = bb.utils.which(os.getenv('PATH'), "gpg-agent")
20        # Without this we see "Cannot allocate memory" errors when running processes in parallel
21        # It needs to be set for any gpg command since any agent launched can stick around in memory
22        # and this parameter must be set.
23        if self.gpg_agent_bin:
24            self.gpg_cmd += ["--agent-program=%s|--auto-expand-secmem" % (self.gpg_agent_bin)]
25        self.gpg_path = d.getVar('GPG_PATH')
26        self.rpm_bin = bb.utils.which(os.getenv('PATH'), "rpmsign")
27        self.gpg_version = self.get_gpg_version()
28
29
30    def export_pubkey(self, output_file, keyid, armor=True):
31        """Export GPG public key to a file"""
32        cmd = self.gpg_cmd + ["--no-permission-warning", "--batch", "--yes", "--export", "-o", output_file]
33        if self.gpg_path:
34            cmd += ["--homedir", self.gpg_path]
35        if armor:
36            cmd += ["--armor"]
37        cmd += [keyid]
38        subprocess.check_output(cmd, stderr=subprocess.STDOUT)
39
40    def sign_rpms(self, files, keyid, passphrase, digest, sign_chunk, fsk=None, fsk_password=None):
41        """Sign RPM files"""
42
43        cmd = self.rpm_bin + " --addsign --define '_gpg_name %s'  " % keyid
44        gpg_args = '--no-permission-warning --batch --passphrase=%s --agent-program=%s|--auto-expand-secmem' % (passphrase, self.gpg_agent_bin)
45        if self.gpg_version > (2,1,):
46            gpg_args += ' --pinentry-mode=loopback'
47        cmd += "--define '_gpg_sign_cmd_extra_args %s' " % gpg_args
48        cmd += "--define '_binary_filedigest_algorithm %s' " % digest
49        if self.gpg_bin:
50            cmd += "--define '__gpg %s' " % self.gpg_bin
51        if self.gpg_path:
52            cmd += "--define '_gpg_path %s' " % self.gpg_path
53        if fsk:
54            cmd += "--signfiles --fskpath %s " % fsk
55            if fsk_password:
56                cmd += "--define '_file_signing_key_password %s' " % fsk_password
57
58        # Sign in chunks
59        for i in range(0, len(files), sign_chunk):
60            subprocess.check_output(shlex.split(cmd + ' '.join(files[i:i+sign_chunk])), stderr=subprocess.STDOUT)
61
62    def detach_sign(self, input_file, keyid, passphrase_file, passphrase=None, armor=True):
63        """Create a detached signature of a file"""
64
65        if passphrase_file and passphrase:
66            raise Exception("You should use either passphrase_file of passphrase, not both")
67
68        cmd = self.gpg_cmd + ['--detach-sign', '--no-permission-warning', '--batch',
69               '--no-tty', '--yes', '--passphrase-fd', '0', '-u', keyid]
70
71        if self.gpg_path:
72            cmd += ['--homedir', self.gpg_path]
73        if armor:
74            cmd += ['--armor']
75
76        #gpg > 2.1 supports password pipes only through the loopback interface
77        #gpg < 2.1 errors out if given unknown parameters
78        if self.gpg_version > (2,1,):
79            cmd += ['--pinentry-mode', 'loopback']
80
81        cmd += [input_file]
82
83        try:
84            if passphrase_file:
85                with open(passphrase_file) as fobj:
86                    passphrase = fobj.readline();
87
88            job = subprocess.Popen(cmd, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
89            (_, stderr) = job.communicate(passphrase.encode("utf-8"))
90
91            if job.returncode:
92                bb.fatal("GPG exited with code %d: %s" % (job.returncode, stderr.decode("utf-8")))
93
94        except IOError as e:
95            bb.error("IO error (%s): %s" % (e.errno, e.strerror))
96            raise Exception("Failed to sign '%s'" % input_file)
97
98        except OSError as e:
99            bb.error("OS error (%s): %s" % (e.errno, e.strerror))
100            raise Exception("Failed to sign '%s" % input_file)
101
102
103    def get_gpg_version(self):
104        """Return the gpg version as a tuple of ints"""
105        try:
106            cmd = self.gpg_cmd + ["--version", "--no-permission-warning"]
107            ver_str = subprocess.check_output(cmd).split()[2].decode("utf-8")
108            return tuple([int(i) for i in ver_str.split("-")[0].split('.')])
109        except subprocess.CalledProcessError as e:
110            bb.fatal("Could not get gpg version: %s" % e)
111
112
113    def verify(self, sig_file):
114        """Verify signature"""
115        cmd = self.gpg_cmd + [" --verify", "--no-permission-warning"]
116        if self.gpg_path:
117            cmd += ["--homedir", self.gpg_path]
118
119        cmd += [sig_file]
120        status = subprocess.call(cmd)
121        ret = False if status else True
122        return ret
123
124
125def get_signer(d, backend):
126    """Get signer object for the specified backend"""
127    # Use local signing by default
128    if backend == 'local':
129        return LocalSigner(d)
130    else:
131        bb.fatal("Unsupported signing backend '%s'" % backend)
132