meta/lib: new module for handling GPG signing

Add a new Python module (oe.gpg_sign) for handling GPG signing
operations, i.e. currently package and package feed signing. The purpose
is to be able to more easily support various signing backends and to be
able to centralise signing functionality into one place (e.g.  package
signing and sstate signing). Currently, only local signing with gpg is
implemented.

[YOCTO #8755]

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>

5 files changed, 116 insertions, 70 deletions

diff --git a/meta/classes/sign_package_feed.bbclass b/meta/classes/sign_package_feed.bbclass
index d89bc0b195..d5df8afb9f 100644
--- a/meta/classes/sign_package_feed.bbclass
+++ b/meta/classes/sign_package_feed.bbclass
@@ -6,6 +6,10 @@
 #           Path to a file containing the passphrase of the signing key.
 # PACKAGE_FEED_GPG_NAME
 #           Name of the key to sign with. May be key id or key name.
+# PACKAGE_FEED_GPG_BACKEND
+#           Optional variable for specifying the backend to use for signing.
+#           Currently the only available option is 'local', i.e. local signing
+#           on the build host.
 # GPG_BIN
 #           Optional variable for specifying the gpg binary/wrapper to use for
 #           signing.
@@ -15,6 +19,8 @@
 inherit sanity
 
 PACKAGE_FEED_SIGN = '1'
+PACKAGE_FEED_GPG_BACKEND ?= 'local'
+
 
 python () {
     # Check sanity of configuration
diff --git a/meta/classes/sign_rpm.bbclass b/meta/classes/sign_rpm.bbclass
index 7906b6413b..8bcabeec91 100644
--- a/meta/classes/sign_rpm.bbclass
+++ b/meta/classes/sign_rpm.bbclass
@@ -5,6 +5,10 @@
 #           Path to a file containing the passphrase of the signing key.
 # RPM_GPG_NAME
 #           Name of the key to sign with. May be key id or key name.
+# RPM_GPG_BACKEND
+#           Optional variable for specifying the backend to use for signing.
+#           Currently the only available option is 'local', i.e. local signing
+#           on the build host.
 # GPG_BIN
 #           Optional variable for specifying the gpg binary/wrapper to use for
 #           signing.
@@ -14,6 +18,7 @@
 inherit sanity
 
 RPM_SIGN_PACKAGES='1'
+RPM_GPG_BACKEND ?= 'local'
 
 
 python () {
@@ -27,47 +32,17 @@ python () {
                                             'RPM-GPG-PUBKEY'))
 }
 
-
-def rpmsign_wrapper(d, files, passphrase, gpg_name=None):
-    import pexpect
-
-    # Find the correct rpm binary
-    rpm_bin_path = d.getVar('STAGING_BINDIR_NATIVE', True) + '/rpm'
-    cmd = rpm_bin_path + " --addsign --define '_gpg_name %s' " % gpg_name
-    if d.getVar('GPG_BIN', True):
-        cmd += "--define '%%__gpg %s' " % d.getVar('GPG_BIN', True)
-    if d.getVar('GPG_PATH', True):
-        cmd += "--define '_gpg_path %s' " % d.getVar('GPG_PATH', True)
-    cmd += ' '.join(files)
-
-    # Need to use pexpect for feeding the passphrase
-    proc = pexpect.spawn(cmd)
-    try:
-        proc.expect_exact('Enter pass phrase:', timeout=15)
-        proc.sendline(passphrase)
-        proc.expect(pexpect.EOF, timeout=900)
-        proc.close()
-    except pexpect.TIMEOUT as err:
-        bb.warn('rpmsign timeout: %s' % err)
-        proc.terminate()
-    else:
-        if os.WEXITSTATUS(proc.status) or not os.WIFEXITED(proc.status):
-            bb.warn('rpmsign failed: %s' % proc.before.strip())
-    return proc.exitstatus
-
-
 python sign_rpm () {
     import glob
+    from oe.gpg_sign import get_signer
 
-    with open(d.getVar("RPM_GPG_PASSPHRASE_FILE", True)) as fobj:
-        rpm_gpg_passphrase = fobj.readlines()[0].rstrip('\n')
-
-    rpm_gpg_name = (d.getVar("RPM_GPG_NAME", True) or "")
-
+    signer = get_signer(d,
+                        d.getVar('RPM_GPG_BACKEND', True),
+                        d.getVar('RPM_GPG_NAME', True),
+                        d.getVar('RPM_GPG_PASSPHRASE_FILE', True))
     rpms = glob.glob(d.getVar('RPM_PKGWRITEDIR', True) + '/*')
 
-    if rpmsign_wrapper(d, rpms, rpm_gpg_passphrase, rpm_gpg_name) != 0:
-        raise bb.build.FuncFailed("RPM signing failed")
+    signer.sign_rpms(rpms)
 }
 
 do_package_index[depends] += "signing-keys:do_export_public_keys"
diff --git a/meta/lib/oe/gpg_sign.py b/meta/lib/oe/gpg_sign.py
new file mode 100644
index 0000000000..55abad8ffc
--- /dev/null
+++ b/meta/lib/oe/gpg_sign.py
@@ -0,0 +1,76 @@
+"""Helper module for GPG signing"""
+import os
+
+import bb
+import oe.utils
+
+class LocalSigner(object):
+    """Class for handling local (on the build host) signing"""
+    def __init__(self, d, keyid, passphrase_file):
+        self.keyid = keyid
+        self.passphrase_file = passphrase_file
+        self.gpg_bin = d.getVar('GPG_BIN', True) or \
+                  bb.utils.which(os.getenv('PATH'), 'gpg')
+        self.gpg_path = d.getVar('GPG_PATH', True)
+        self.rpm_bin = bb.utils.which(os.getenv('PATH'), "rpm")
+
+    def export_pubkey(self, output_file):
+        """Export GPG public key to a file"""
+        cmd = '%s --batch --yes --export --armor -o %s ' % \
+                (self.gpg_bin, output_file)
+        if self.gpg_path:
+            cmd += "--homedir %s " % self.gpg_path
+        cmd += self.keyid
+        status, output = oe.utils.getstatusoutput(cmd)
+        if status:
+            raise bb.build.FuncFailed('Failed to export gpg public key (%s): %s' %
+                                      (self.keyid, output))
+
+    def sign_rpms(self, files):
+        """Sign RPM files"""
+        import pexpect
+
+        cmd = self.rpm_bin + " --addsign --define '_gpg_name %s' " % self.keyid
+        if self.gpg_bin:
+            cmd += "--define '%%__gpg %s' " % self.gpg_bin
+        if self.gpg_path:
+            cmd += "--define '_gpg_path %s' " % self.gpg_path
+        cmd += ' '.join(files)
+
+        # Need to use pexpect for feeding the passphrase
+        proc = pexpect.spawn(cmd)
+        try:
+            proc.expect_exact('Enter pass phrase:', timeout=15)
+            with open(self.passphrase_file) as fobj:
+                proc.sendline(fobj.readline().rstrip('\n'))
+            proc.expect(pexpect.EOF, timeout=900)
+            proc.close()
+        except pexpect.TIMEOUT as err:
+            bb.error('rpmsign timeout: %s' % err)
+            proc.terminate()
+        if os.WEXITSTATUS(proc.status) or not os.WIFEXITED(proc.status):
+            bb.error('rpmsign failed: %s' % proc.before.strip())
+            raise bb.build.FuncFailed("Failed to sign RPM packages")
+
+    def detach_sign(self, input_file):
+        """Create a detached signature of a file"""
+        cmd = "%s --detach-sign --armor --batch --no-tty --yes " \
+                  "--passphrase-file '%s' -u '%s' " % \
+                  (self.gpg_bin, self.passphrase_file, self.keyid)
+        if self.gpg_path:
+            gpg_cmd += "--homedir %s " % self.gpg_path
+        cmd += input_file
+        status, output = oe.utils.getstatusoutput(cmd)
+        if status:
+            raise bb.build.FuncFailed("Failed to create signature for '%s': %s" %
+                                      (input_file, output))
+
+
+def get_signer(d, backend, keyid, passphrase_file):
+    """Get signer object for the specified backend"""
+    # Use local signing by default
+    if backend == 'local':
+        return LocalSigner(d, keyid, passphrase_file)
+    else:
+        bb.fatal("Unsupported signing backend '%s'" % backend)
+
diff --git a/meta/lib/oe/package_manager.py b/meta/lib/oe/package_manager.py
index 5b87f45127..3f9e4e3b60 100644
--- a/meta/lib/oe/package_manager.py
+++ b/meta/lib/oe/package_manager.py
@@ -9,6 +9,7 @@ import bb
 import tempfile
 import oe.utils
 import string
+from oe.gpg_sign import get_signer
 
 # this can be used by all PM backends to create the index files in parallel
 def create_index(arg):
@@ -109,16 +110,14 @@ class RpmIndexer(Indexer):
 
         rpm_createrepo = bb.utils.which(os.getenv('PATH'), "createrepo")
         if self.d.getVar('PACKAGE_FEED_SIGN', True) == '1':
-            pkgfeed_gpg_name = self.d.getVar('PACKAGE_FEED_GPG_NAME', True)
-            pkgfeed_gpg_pass = self.d.getVar('PACKAGE_FEED_GPG_PASSPHRASE_FILE', True)
+            signer = get_signer(self.d,
+                                self.d.getVar('PACKAGE_FEED_GPG_BACKEND', True),
+                                self.d.getVar('PACKAGE_FEED_GPG_NAME', True),
+                                self.d.getVar('PACKAGE_FEED_GPG_PASSPHRASE_FILE', True))
         else:
-            pkgfeed_gpg_name = None
-            pkgfeed_gpg_pass = None
-        gpg_bin = self.d.getVar('GPG_BIN', True) or \
-                  bb.utils.which(os.getenv('PATH'), "gpg")
-
+            signer = None
         index_cmds = []
-        repo_sign_cmds = []
+        repomd_files = []
         rpm_dirs_found = False
         for arch in archs:
             dbpath = os.path.join(self.d.getVar('WORKDIR', True), 'rpmdb', arch)
@@ -130,15 +129,7 @@ class RpmIndexer(Indexer):
 
             index_cmds.append("%s --dbpath %s --update -q %s" % \
                              (rpm_createrepo, dbpath, arch_dir))
-            if pkgfeed_gpg_name:
-                repomd_file = os.path.join(arch_dir, 'repodata', 'repomd.xml')
-                gpg_cmd = "%s --detach-sign --armor --batch --no-tty --yes " \
-                          "--passphrase-file '%s' -u '%s' " % \
-                          (gpg_bin, pkgfeed_gpg_pass, pkgfeed_gpg_name)
-                if self.d.getVar('GPG_PATH', True):
-                    gpg_cmd += "--homedir %s " % self.d.getVar('GPG_PATH', True)
-                gpg_cmd += repomd_file
-                repo_sign_cmds.append(gpg_cmd)
+            repomd_files.append(os.path.join(arch_dir, 'repodata', 'repomd.xml'))
 
             rpm_dirs_found = True
 
@@ -151,9 +142,9 @@ class RpmIndexer(Indexer):
         if result:
             bb.fatal('%s' % ('\n'.join(result)))
         # Sign repomd
-        result = oe.utils.multiprocess_exec(repo_sign_cmds, create_index)
-        if result:
-            bb.fatal('%s' % ('\n'.join(result)))
+        if signer:
+            for repomd in repomd_files:
+                signer.detach_sign(repomd)
         # Copy pubkey(s) to repo
         distro_version = self.d.getVar('DISTRO_VERSION', True) or "oe.0"
         if self.d.getVar('RPM_SIGN_PACKAGES', True) == '1':
diff --git a/meta/recipes-core/meta/signing-keys.bb b/meta/recipes-core/meta/signing-keys.bb
index cc401f3b6c..d7aa79d49f 100644
--- a/meta/recipes-core/meta/signing-keys.bb
+++ b/meta/recipes-core/meta/signing-keys.bb
@@ -20,26 +20,24 @@ do_populate_sysroot[noexec] = "1"
 
 EXCLUDE_FROM_WORLD = "1"
 
-def export_gpg_pubkey(d, keyid, path):
-    import bb
-    gpg_bin = d.getVar('GPG_BIN', True) or \
-              bb.utils.which(os.getenv('PATH'), "gpg")
-    cmd = '%s --batch --yes --export --armor -o %s %s' % \
-          (gpg_bin, path, keyid)
-    status, output = oe.utils.getstatusoutput(cmd)
-    if status:
-        raise bb.build.FuncFailed('Failed to export gpg public key (%s): %s' %
-                                  (keyid, output))
 
 python do_export_public_keys () {
+    from oe.gpg_sign import get_signer
+
     if d.getVar("RPM_SIGN_PACKAGES", True):
         # Export public key of the rpm signing key
-        export_gpg_pubkey(d, d.getVar("RPM_GPG_NAME", True),
-                          d.getVar('RPM_GPG_PUBKEY', True))
+        signer = get_signer(d,
+                            d.getVar('RPM_GPG_BACKEND', True),
+                            d.getVar('RPM_GPG_NAME', True),
+                            d.getVar('RPM_GPG_PASSPHRASE_FILE', True))
+        signer.export_pubkey(d.getVar('RPM_GPG_PUBKEY', True))
 
     if d.getVar('PACKAGE_FEED_SIGN', True) == '1':
         # Export public key of the feed signing key
-        export_gpg_pubkey(d, d.getVar("PACKAGE_FEED_GPG_NAME", True),
-                          d.getVar('PACKAGE_FEED_GPG_PUBKEY', True))
+        signer = get_signer(d,
+                            d.getVar('PACKAGE_FEED_GPG_BACKEND', True),
+                            d.getVar('PACKAGE_FEED_GPG_NAME', True),
+                            d.getVar('PACKAGE_FEED_GPG_PASSPHRASE_FILE', True))
+        signer.export_pubkey(d.getVar('PACKAGE_FEED_GPG_PUBKEY', True))
 }
 addtask do_export_public_keys before do_build