localmodconfig: Reset certificate paths

When using `make localmodconfig` and friends, if the input config comes
from a kernel that was built in a different environment (for example, the
canonical case of using localmodconfig to trim a distribution kernel
config) the key files for module signature checking will not be available
and should be regenerated or omitted. Otherwise, the user will be faced
with annoying errors when trying to build with the generated .config:

make[1]: *** No rule to make target 'keyring.crt', needed by 'certs/x509_certificate_list'.  Stop.
Makefile:1576: recipe for target 'certs/' failed

Link: http://lkml.kernel.org/r/1461696721-3001-1-git-send-email-bpoirier@suse.com
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl
index 01b53eccfe2f675ee33b37a8c9d9f2e2dc031810..95a6f2b888d486295a41578aa58e6c6e5e43ffb4 100755 (executable)
--- a/scripts/kconfig/streamline_config.pl
+++ b/scripts/kconfig/streamline_config.pl
@@ -610,6 +610,40 @@ foreach my $line (@config_file) {
        next;
     }
 
+    if (/CONFIG_MODULE_SIG_KEY="(.+)"/) {
+        my $orig_cert = $1;
+        my $default_cert = "certs/signing_key.pem";
+
+        # Check that the logic in this script still matches the one in Kconfig
+        if (!defined($depends{"MODULE_SIG_KEY"}) ||
+            $depends{"MODULE_SIG_KEY"} !~ /"\Q$default_cert\E"/) {
+            print STDERR "WARNING: MODULE_SIG_KEY assertion failure, ",
+                "update needed to ", __FILE__, " line ", __LINE__, "\n";
+            print;
+        } elsif ($orig_cert ne $default_cert && ! -f $orig_cert) {
+            print STDERR "Module signature verification enabled but ",
+                "module signing key \"$orig_cert\" not found. Resetting ",
+                "signing key to default value.\n";
+            print "CONFIG_MODULE_SIG_KEY=\"$default_cert\"\n";
+        } else {
+            print;
+        }
+        next;
+    }
+
+    if (/CONFIG_SYSTEM_TRUSTED_KEYS="(.+)"/) {
+        my $orig_keys = $1;
+
+        if (! -f $orig_keys) {
+            print STDERR "System keyring enabled but keys \"$orig_keys\" ",
+                "not found. Resetting keys to default value.\n";
+            print "CONFIG_SYSTEM_TRUSTED_KEYS=\"\"\n";
+        } else {
+            print;
+        }
+        next;
+    }
+
     if (/^(CONFIG.*)=(m|y)/) {
        if (defined($configs{$1})) {
            if ($localyesconfig) {