extract-cert: Cope with multiple X.509 certificates in a single file

This is not required for the module signing key, although it doesn't do any
harm — it just means that any additional certs in the PEM file are also
trusted by the kernel.

But it does allow us to use the extract-cert tool for processing the extra
certs from CONFIG_SYSTEM_TRUSTED_KEYS, instead of that horrid awk|base64
hack.

Also cope with being invoked with no input file, creating an empty output
file as a result.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/scripts/extract-cert.c b/scripts/extract-cert.c
index 4fd5b2f07b459ee43f59f2af3d5b7cbced6f0b48..fd0db015c65c271d807bb4b3b8dfc44db219c7e3 100644 (file)
--- a/scripts/extract-cert.c
+++ b/scripts/extract-cert.c
@@ -73,17 +73,34 @@ static void drain_openssl_errors(void)
        } while(0)
 
 static const char *key_pass;
+static BIO *wb;
+static char *cert_dst;
+int kbuild_verbose;
+
+static void write_cert(X509 *x509)
+{
+       char buf[200];
+
+       if (!wb) {
+               wb = BIO_new_file(cert_dst, "wb");
+               ERR(!wb, "%s", cert_dst);
+       }
+       X509_NAME_oneline(X509_get_subject_name(x509), buf, sizeof(buf));
+       ERR(!i2d_X509_bio(wb, x509), cert_dst);
+       if (kbuild_verbose)
+               fprintf(stderr, "Extracted cert: %s\n", buf);
+}
 
 int main(int argc, char **argv)
 {
-       char *cert_src, *cert_dst;
-       X509 *x509;
-       BIO *b;
+       char *cert_src;
 
        OpenSSL_add_all_algorithms();
        ERR_load_crypto_strings();
        ERR_clear_error();
 
+       kbuild_verbose = atoi(getenv("KBUILD_VERBOSE")?:"0");
+
         key_pass = getenv("KBUILD_SIGN_PIN");
 
        if (argc != 3)
@@ -92,7 +109,13 @@ int main(int argc, char **argv)
        cert_src = argv[1];
        cert_dst = argv[2];
 
-       if (!strncmp(cert_src, "pkcs11:", 7)) {
+       if (!cert_src[0]) {
+               /* Invoked with no input; create empty file */
+               FILE *f = fopen(cert_dst, "wb");
+               ERR(!f, "%s", cert_dst);
+               fclose(f);
+               exit(0);
+       } else if (!strncmp(cert_src, "pkcs11:", 7)) {
                ENGINE *e;
                struct {
                        const char *cert_id;
@@ -114,19 +137,30 @@ int main(int argc, char **argv)
                        ERR(!ENGINE_ctrl_cmd_string(e, "PIN", key_pass, 0), "Set PKCS#11 PIN");
                ENGINE_ctrl_cmd(e, "LOAD_CERT_CTRL", 0, &parms, NULL, 1);
                ERR(!parms.cert, "Get X.509 from PKCS#11");
-               x509 = parms.cert;
+               write_cert(parms.cert);
        } else {
+               BIO *b;
+               X509 *x509;
+
                b = BIO_new_file(cert_src, "rb");
                ERR(!b, "%s", cert_src);
-               x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
-               ERR(!x509, "%s", cert_src);
-               BIO_free(b);
+
+               while (1) {
+                       x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
+                       if (wb && !x509) {
+                               unsigned long err = ERR_peek_last_error();
+                               if (ERR_GET_LIB(err) == ERR_LIB_PEM &&
+                                   ERR_GET_REASON(err) == PEM_R_NO_START_LINE) {
+                                       ERR_clear_error();
+                                       break;
+                               }
+                       }
+                       ERR(!x509, "%s", cert_src);
+                       write_cert(x509);
+               }
        }
 
-       b = BIO_new_file(cert_dst, "wb");
-       ERR(!b, "%s", cert_dst);
-       ERR(!i2d_X509_bio(b, x509), cert_dst);
-       BIO_free(b);
+       BIO_free(wb);
 
        return 0;
 }