mkimage: Support signing 'auto' FITs

This adds support for signing images in auto-generated FITs. To do this,
we need to add a signature node. The algorithm name property already has
its own option, but we need one for the key name hint. We could have
gone the -G route and added an explicit name for the public key (like
what is done for the private key). However, many places assume the
public key can be constructed from the key dir and hint, and I don't
want to do the refactoring necessary.

As a consequence of this, it is now easier to add public keys to an
existing image without signing something. This could be done all along,
but now you don't have to create an its just to do it. Ideally, we
wouldn't create a FIT at the end. This could be done by calling
fit_image_setup_sig/info.crypto->add_verify_data directly.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>

diff --git a/doc/mkimage.1 b/doc/mkimage.1
index 878db904757a526755379799bdf8e38b5342d397..759dc2d12f5d787b5646dbcf7649e76365bab38b 100644 (file)
--- a/doc/mkimage.1
+++ b/doc/mkimage.1
@@ -218,6 +218,13 @@ CONFIG_OF_CONTROL in U-Boot.
 Specifies the private key file to use when signing. This option may be used
 instead of \-k.
 
+.TP
+.BI "\-g [" "key_name_hint" "]"
+Sets the key-name-hint property when used with \-f auto. This is the <name>
+part of the key. The directory part is set by \-k. This option also indicates
+that the images included in the FIT should be signed. If this option is
+specified, \-o must be specified as well.
+
 .TP
 .BI "\-o [" "signing algorithm" "]"
 Specifies the algorithm to be used for signing a FIT image. The default is
@@ -278,6 +285,15 @@ skipping those for which keys cannot be found. Also add a comment.
 .B -c """Kernel 3.8 image for production devices""" kernel.itb
 .fi
 
+.P
+Add public keys to u-boot.dtb without needing a FIT to sign. This will also
+create a FIT containing an images node with no data named unused.itb.
+.nf
+.B mkimage -f auto -d /dev/null -k /public/signing-keys -g dev \\\\
+.br
+.B -o sha256,rsa2048 -K u-boot.dtb unused.itb
+.fi
+
 .P
 Update an existing FIT image, signing it with additional keys.
 Add corresponding public keys into u-boot.dtb. This will resign all images
@@ -306,6 +322,14 @@ automatic mode. No .its file is required.
 .B -c """Kernel 4.4 image for production devices""" -d vmlinuz \\\\
 .B -b /path/to/rk3288-firefly.dtb -b /path/to/rk3288-jerry.dtb kernel.itb
 .fi
+.P
+Create a FIT image containing a signed kernel, using automatic mode. No .its
+file is required.
+.nf
+.B mkimage -f auto -A arm -O linux -T kernel -C none -a 43e00000 -e 0 \\\\
+.br
+.B -d vmlinuz -k /secret/signing-keys -g dev -o sha256,rsa2048 kernel.itb
+.fi
 
 .SH HOMEPAGE
 http://www.denx.de/wiki/U-Boot/WebHome

diff --git a/tools/fit_image.c b/tools/fit_image.c
index 1884a2eb0b95114254342ffad2fdaa1d1b6a391e..979f2411ee0e897138ff2d46d8f3befb5ab480da 100644 (file)
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -199,15 +199,36 @@ static void get_basename(char *str, int size, const char *fname)
 }
 
 /**
- * add_crc_node() - Add a hash node to request a CRC checksum for an image
+ * add_hash_node() - Add a hash or signature node
  *
+ * @params: Image parameters
  * @fdt: Device tree to add to (in sequential-write mode)
+ *
+ * If there is a key name hint, try to sign the images. Otherwise, just add a
+ * CRC.
+ *
+ * Return: 0 on success, or -1 on failure
  */
-static void add_crc_node(void *fdt)
+static int add_hash_node(struct image_tool_params *params, void *fdt)
 {
-       fdt_begin_node(fdt, "hash-1");
-       fdt_property_string(fdt, FIT_ALGO_PROP, "crc32");
+       if (params->keyname) {
+               if (!params->algo_name) {
+                       fprintf(stderr,
+                               "%s: Algorithm name must be specified\n",
+                               params->cmdname);
+                       return -1;
+               }
+
+               fdt_begin_node(fdt, "signature-1");
+               fdt_property_string(fdt, FIT_ALGO_PROP, params->algo_name);
+               fdt_property_string(fdt, FIT_KEY_HINT, params->keyname);
+       } else {
+               fdt_begin_node(fdt, "hash-1");
+               fdt_property_string(fdt, FIT_ALGO_PROP, "crc32");
+       }
+
        fdt_end_node(fdt);
+       return 0;
 }
 
 /**
@@ -248,7 +269,9 @@ static int fit_write_images(struct image_tool_params *params, char *fdt)
        ret = fdt_property_file(params, fdt, FIT_DATA_PROP, params->datafile);
        if (ret)
                return ret;
-       add_crc_node(fdt);
+       ret = add_hash_node(params, fdt);
+       if (ret)
+               return ret;
        fdt_end_node(fdt);
 
        /* Now the device tree files if available */
@@ -271,7 +294,9 @@ static int fit_write_images(struct image_tool_params *params, char *fdt)
                                    genimg_get_arch_short_name(params->arch));
                fdt_property_string(fdt, FIT_COMP_PROP,
                                    genimg_get_comp_short_name(IH_COMP_NONE));
-               add_crc_node(fdt);
+               ret = add_hash_node(params, fdt);
+               if (ret)
+                       return ret;
                fdt_end_node(fdt);
        }
 
@@ -289,7 +314,9 @@ static int fit_write_images(struct image_tool_params *params, char *fdt)
                                        params->fit_ramdisk);
                if (ret)
                        return ret;
-               add_crc_node(fdt);
+               ret = add_hash_node(params, fdt);
+               if (ret)
+                       return ret;
                fdt_end_node(fdt);
        }
 

diff --git a/tools/imagetool.h b/tools/imagetool.h
index 05dd94d108474842b88eb8a38a2db9a03d13fc33..ca7c2e48ba914441758a69536a548e3d539b7d20 100644 (file)
--- a/tools/imagetool.h
+++ b/tools/imagetool.h
@@ -71,6 +71,7 @@ struct image_tool_params {
        const char *keydir;     /* Directory holding private keys */
        const char *keydest;    /* Destination .dtb for public key */
        const char *keyfile;    /* Filename of private or public key */
+       const char *keyname;    /* Key name "hint" */
        const char *comment;    /* Comment to add to signature node */
        /* Algorithm name to use for hashing/signing or NULL to use the one
         * specified in the its */

diff --git a/tools/mkimage.c b/tools/mkimage.c
index 5c6a60e85136074d98b8ad5046bb7715a2b7b1ab..0e1198b411325a685e60116e445fbe0158cd0d08 100644 (file)
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -119,6 +119,7 @@ static void usage(const char *msg)
                "Signing / verified boot options: [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
                "          -k => set directory containing private keys\n"
                "          -K => write public keys to this .dtb file\n"
+               "          -g => set key name hint\n"
                "          -G => use this signing key (in lieu of -k)\n"
                "          -c => add comment in signature node\n"
                "          -F => re-sign existing FIT image\n"
@@ -163,7 +164,7 @@ static void process_args(int argc, char **argv)
        int opt;
 
        while ((opt = getopt(argc, argv,
-                  "a:A:b:B:c:C:d:D:e:Ef:FG:k:i:K:ln:N:p:o:O:rR:qstT:vVx")) != -1) {
+                  "a:A:b:B:c:C:d:D:e:Ef:Fg:G:k:i:K:ln:N:p:o:O:rR:qstT:vVx")) != -1) {
                switch (opt) {
                case 'a':
                        params.addr = strtoull(optarg, &ptr, 16);
@@ -239,6 +240,8 @@ static void process_args(int argc, char **argv)
                        params.type = IH_TYPE_FLATDT;
                        params.fflag = 1;
                        break;
+               case 'g':
+                       params.keyname = optarg;
                case 'G':
                        params.keyfile = optarg;
                        break;