[U-Boot] [PATCH v2 32/45] image: Support signing of images
Simon Glass
sjg at chromium.org
Tue Mar 19 00:51:52 CET 2013
Add support for signing images using a new signature node. The process
is handled by fdt_add_verification_data() which now takes parameters to
provide the keys and related information.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2:
- Adjust how signing enable works in image.h
- Fix FDT error handling in fit_image_write_sig()
- Fix checkpatch checks about parenthesis alignment
- Fix checkpatch warnings about split strings
- Require CONFIG_FIT_SIGNATURE in image.h for mkimage to support signing
common/image-fit.c | 85 ++++++++++++++-----
common/image-sig.c | 148 ++++++++++++++++++++++++++++++++
doc/uImage.FIT/sign-images.its | 42 ++++++++++
include/image.h | 59 ++++++++++++-
tools/fit_image.c | 2 +-
tools/image-host.c | 186 ++++++++++++++++++++++++++++++++++++++---
6 files changed, 484 insertions(+), 38 deletions(-)
create mode 100644 doc/uImage.FIT/sign-images.its
diff --git a/common/image-fit.c b/common/image-fit.c
index 5dcb0c6..30790d3 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -31,6 +31,8 @@
#include <time.h>
#else
#include <common.h>
+#include <errno.h>
+DECLARE_GLOBAL_DATA_PTR;
#endif /* !USE_HOSTCC*/
#include <bootstage.h>
@@ -233,42 +235,45 @@ void fit_print_contents(const void *fit)
* @fit: pointer to the FIT format image header
* @noffset: offset of the hash node
* @p: pointer to prefix string
+ * @type: Type of information to print ("hash" or "sign")
*
* fit_image_print_data() lists properies for the processed hash node
*
+ * This function avoid using puts() since it prints a newline on the host
+ * but does not in U-Boot.
+ *
* returns:
* no returned results
*/
-static void fit_image_print_data(const void *fit, int noffset, const char *p)
+static void fit_image_print_data(const void *fit, int noffset, const char *p,
+ const char *type)
{
- char *algo;
+ const char *keyname;
uint8_t *value;
int value_len;
- int i, ret;
-
- /*
- * Check subnode name, must be equal to "hash".
- * Multiple hash nodes require unique unit node
- * names, e.g. hash at 1, hash at 2, etc.
- */
- if (strncmp(fit_get_name(fit, noffset, NULL),
- FIT_HASH_NODENAME,
- strlen(FIT_HASH_NODENAME)) != 0)
- return;
+ char *algo;
+ int required;
+ int ret, i;
- debug("%s Hash node: '%s'\n", p,
+ debug("%s %s node: '%s'\n", p, type,
fit_get_name(fit, noffset, NULL));
-
- printf("%s Hash algo: ", p);
+ printf("%s %s algo: ", p, type);
if (fit_image_hash_get_algo(fit, noffset, &algo)) {
printf("invalid/unsupported\n");
return;
}
- printf("%s\n", algo);
+ printf("%s", algo);
+ keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
+ required = fdt_getprop(fit, noffset, "required", NULL) != NULL;
+ if (keyname)
+ printf(":%s", keyname);
+ if (required)
+ printf(" (required)");
+ printf("\n");
ret = fit_image_hash_get_value(fit, noffset, &value,
&value_len);
- printf("%s Hash value: ", p);
+ printf("%s %s value: ", p, type);
if (ret) {
printf("unavailable\n");
} else {
@@ -277,7 +282,18 @@ static void fit_image_print_data(const void *fit, int noffset, const char *p)
printf("\n");
}
- debug("%s Hash len: %d\n", p, value_len);
+ debug("%s %s len: %d\n", p, type, value_len);
+
+ /* Signatures have a time stamp */
+ if (IMAGE_ENABLE_TIMESTAMP && keyname) {
+ time_t timestamp;
+
+ printf("%s Timestamp: ", p);
+ if (fit_get_timestamp(fit, noffset, ×tamp))
+ printf("unavailable\n");
+ else
+ genimg_print_time(timestamp);
+ }
}
/**
@@ -302,8 +318,12 @@ static void fit_image_print_verification_data(const void *fit, int noffset,
* names, e.g. hash at 1, hash at 2, signature at 1, signature at 2, etc.
*/
name = fit_get_name(fit, noffset, NULL);
- if (!strncmp(name, FIT_HASH_NODENAME, strlen(FIT_HASH_NODENAME)))
- fit_image_print_data(fit, noffset, p);
+ if (!strncmp(name, FIT_HASH_NODENAME, strlen(FIT_HASH_NODENAME))) {
+ fit_image_print_data(fit, noffset, p, "Hash");
+ } else if (!strncmp(name, FIT_SIG_NODENAME,
+ strlen(FIT_SIG_NODENAME))) {
+ fit_image_print_data(fit, noffset, p, "Sign");
+ }
}
/**
@@ -939,14 +959,24 @@ int fit_image_verify(const void *fit, int image_noffset)
{
const void *data;
size_t size;
- int noffset;
+ int noffset = 0;
int ndepth;
char *err_msg = "";
+ int verify_all = 1;
+ int ret;
/* Get image data and data length */
if (fit_image_get_data(fit, image_noffset, &data, &size)) {
err_msg = "Can't get image data/size";
- return 0;
+ goto error;
+ }
+
+ /* Verify all required signatures */
+ if (IMAGE_ENABLE_VERIFY &&
+ fit_image_verify_required_sigs(fit, image_noffset, data, size,
+ gd_fdt_blob(), &verify_all)) {
+ err_msg = "Unable to verify required signature";
+ goto error;
}
/* Process all hash subnodes of the component image node */
@@ -967,6 +997,15 @@ int fit_image_verify(const void *fit, int image_noffset)
&err_msg))
goto error;
puts("+ ");
+ } else if (IMAGE_ENABLE_VERIFY && verify_all &&
+ !strncmp(name, FIT_SIG_NODENAME,
+ strlen(FIT_SIG_NODENAME))) {
+ ret = fit_image_check_sig(fit, noffset, data,
+ size, -1, &err_msg);
+ if (ret)
+ puts("- ");
+ else
+ puts("+ ");
}
}
diff --git a/common/image-sig.c b/common/image-sig.c
index 841c662..1401c75 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -22,6 +22,8 @@
#include <time.h>
#else
#include <common.h>
+#include <malloc.h>
+DECLARE_GLOBAL_DATA_PTR;
#endif /* !USE_HOSTCC*/
#include <errno.h>
#include <image.h>
@@ -40,3 +42,149 @@ struct image_sig_algo *image_get_sig_algo(const char *name)
return NULL;
}
+
+static int fit_image_setup_verify(struct image_sign_info *info,
+ const void *fit, int noffset, int required_keynode,
+ char **err_msgp)
+{
+ char *algo_name;
+
+ if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
+ *err_msgp = "Can't get hash algo property";
+ return -1;
+ }
+ memset(info, '\0', sizeof(*info));
+ info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
+ info->fit = (void *)fit;
+ info->node_offset = noffset;
+ info->algo = image_get_sig_algo(algo_name);
+ info->fdt_blob = gd_fdt_blob();
+ info->required_keynode = required_keynode;
+ printf("%s:%s", algo_name, info->keyname);
+
+ if (!info->algo) {
+ *err_msgp = "Unknown signature algorithm";
+ return -1;
+ }
+
+ return 0;
+}
+
+int fit_image_check_sig(const void *fit, int noffset, const void *data,
+ size_t size, int required_keynode, char **err_msgp)
+{
+ struct image_sign_info info;
+ struct image_region region;
+ uint8_t *fit_value;
+ int fit_value_len;
+
+ *err_msgp = NULL;
+ if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
+ err_msgp))
+ return -1;
+
+ if (fit_image_hash_get_value(fit, noffset, &fit_value,
+ &fit_value_len)) {
+ *err_msgp = "Can't get hash value property";
+ return -1;
+ }
+
+ region.data = data;
+ region.size = size;
+
+ if (info.algo->verify(&info, ®ion, 1, fit_value, fit_value_len)) {
+ *err_msgp = "Verification failed";
+ return -1;
+ }
+
+ return 0;
+}
+
+static int fit_image_verify_sig(const void *fit, int image_noffset,
+ const char *data, size_t size, const void *sig_blob,
+ int sig_offset)
+{
+ int noffset;
+ int ndepth;
+ char *err_msg = "";
+ int verified = 0;
+ int ret;
+
+ /* Process all hash subnodes of the component image node */
+ for (ndepth = 0,
+ noffset = fdt_next_subnode(fit, image_noffset, &ndepth);
+ noffset >= 0;
+ noffset = fdt_next_subnode(fit, noffset, &ndepth)) {
+ const char *name = fit_get_name(fit, noffset, NULL);
+
+ if (!strncmp(name, FIT_SIG_NODENAME,
+ strlen(FIT_SIG_NODENAME))) {
+ ret = fit_image_check_sig(fit, noffset, data,
+ size, -1, &err_msg);
+ if (ret) {
+ puts("- ");
+ } else {
+ puts("+ ");
+ verified = 1;
+ break;
+ }
+ }
+ }
+
+ if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
+ err_msg = "Corrupted or truncated tree";
+ goto error;
+ }
+
+ return verified ? 0 : -EPERM;
+
+error:
+ printf(" error!\n%s for '%s' hash node in '%s' image node\n",
+ err_msg, fit_get_name(fit, noffset, NULL),
+ fit_get_name(fit, image_noffset, NULL));
+ return -1;
+}
+
+int fit_image_verify_required_sigs(const void *fit, int image_noffset,
+ const char *data, size_t size, const void *sig_blob,
+ int *no_sigsp)
+{
+ int verify_count = 0;
+ int ndepth, noffset;
+ int sig_node;
+
+ /* Work out what we need to verify */
+ *no_sigsp = 1;
+ sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
+ if (sig_node < 0) {
+ debug("%s: No signature node found: %s\n", __func__,
+ fdt_strerror(sig_node));
+ return 0;
+ }
+
+ for (ndepth = 0, noffset = fdt_next_subnode(sig_blob, sig_node,
+ &ndepth);
+ noffset >= 0;
+ noffset = fdt_next_subnode(sig_blob, noffset,
+ &ndepth)) {
+ const char *required;
+ int ret;
+
+ required = fdt_getprop(sig_blob, noffset, "required", NULL);
+ if (!required || strcmp(required, "image"))
+ continue;
+ ret = fit_image_verify_sig(fit, image_noffset, data, size,
+ sig_blob, noffset);
+ if (ret) {
+ printf("Failed to verify required signature '%s'\n",
+ fit_get_name(sig_blob, noffset, NULL));
+ return ret;
+ }
+ verify_count++;
+ }
+
+ if (verify_count)
+ *no_sigsp = 0;
+
+ return 0;
+}
diff --git a/doc/uImage.FIT/sign-images.its b/doc/uImage.FIT/sign-images.its
new file mode 100644
index 0000000..f69326a
--- /dev/null
+++ b/doc/uImage.FIT/sign-images.its
@@ -0,0 +1,42 @@
+/dts-v1/;
+
+/ {
+ description = "Chrome OS kernel image with one or more FDT blobs";
+ #address-cells = <1>;
+
+ images {
+ kernel at 1 {
+ data = /incbin/("test-kernel.bin");
+ type = "kernel_noload";
+ arch = "sandbox";
+ os = "linux";
+ compression = "none";
+ load = <0x4>;
+ entry = <0x8>;
+ kernel-version = <1>;
+ signature at 1 {
+ algo = "sha1,rsa2048";
+ key-name-hint = "dev";
+ };
+ };
+ fdt at 1 {
+ description = "snow";
+ data = /incbin/("sandbox-kernel.dtb");
+ type = "flat_dt";
+ arch = "sandbox";
+ compression = "none";
+ fdt-version = <1>;
+ signature at 1 {
+ algo = "sha1,rsa2048";
+ key-name-hint = "dev";
+ };
+ };
+ };
+ configurations {
+ default = "conf at 1";
+ conf at 1 {
+ kernel = "kernel at 1";
+ fdt = "fdt at 1";
+ };
+ };
+};
diff --git a/include/image.h b/include/image.h
index 695473a..99015cd 100644
--- a/include/image.h
+++ b/include/image.h
@@ -618,12 +618,26 @@ int fit_image_hash_get_value(const void *fit, int noffset, uint8_t **value,
int fit_set_timestamp(void *fit, int noffset, time_t timestamp);
/**
- * fit_add_verification_data() - Calculate and add hashes to FIT
+ * fit_add_verification_data() - add verification data to FIT image nodes
*
- * @fit: Fit image to process
- * @return 0 if ok, <0 for error
+ * @keydir: Directory containing keys
+ * @kwydest: FDT blob to write public key information to
+ * @fit: Pointer to the FIT format image header
+ * @comment: Comment to add to signature nodes
+ * @require_keys: Mark all keys as 'required'
+ *
+ * Adds hash values for all component images in the FIT blob.
+ * Hashes are calculated for all component images which have hash subnodes
+ * with algorithm property set to one of the supported hash algorithms.
+ *
+ * Also add signatures if signature nodes are present.
+ *
+ * returns
+ * 0, on success
+ * libfdt error code, on failure
*/
-int fit_add_verification_data(void *fit);
+int fit_add_verification_data(const char *keydir, void *keydest, void *fit,
+ const char *comment, int require_keys);
int fit_image_verify(const void *fit, int noffset);
int fit_all_image_verify(const void *fit);
@@ -762,6 +776,43 @@ struct image_sig_algo {
*/
struct image_sig_algo *image_get_sig_algo(const char *name);
+/**
+ * fit_image_verify_required_sigs() - Verify signatures marked as 'required'
+ *
+ * @fit: FIT to check
+ * @image_noffset: Offset of image node to check
+ * @data: Image data to check
+ * @size: Size of image data
+ * @sig_blob: FDT containing public keys
+ * @no_sigsp: Returns 1 if no signatures were required, and
+ * therefore nothing was checked. The caller may wish
+ * to fall back to other mechanisms, or refuse to
+ * boot.
+ * @return 0 if all verified ok, <0 on error
+ */
+int fit_image_verify_required_sigs(const void *fit, int image_noffset,
+ const char *data, size_t size, const void *sig_blob,
+ int *no_sigsp);
+
+/**
+ * fit_image_check_sig() - Check a single image signature node
+ *
+ * @fit: FIT to check
+ * @noffset: Offset of signature node to check
+ * @data: Image data to check
+ * @size: Size of image data
+ * @required_keynode: Offset in the control FDT of the required key node,
+ * if any. If this is given, then the image wil not
+ * pass verification unless that key is used. If this is
+ * -1 then any signature will do.
+ * @err_msgp: In the event of an error, this will be pointed to a
+ * help error string to display to the user.
+ * @return 0 if all verified ok, <0 on error
+ */
+int fit_image_check_sig(const void *fit, int noffset, const void *data,
+ size_t size, int required_keynode, char **err_msgp);
+
+
#ifndef USE_HOSTCC
static inline int fit_image_check_target_arch(const void *fdt, int node)
{
diff --git a/tools/fit_image.c b/tools/fit_image.c
index 8f51159..e0675d7 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -125,7 +125,7 @@ static int fit_handle_file (struct mkimage_params *params)
}
/* set hashes for images in the blob */
- if (fit_add_verification_data(ptr)) {
+ if (fit_add_verification_data(NULL, NULL, ptr, NULL, 0)) {
fprintf (stderr, "%s Can't add hashes to FIT blob",
params->cmdname);
unlink (tmpfile);
diff --git a/tools/image-host.c b/tools/image-host.c
index 3ba05de..2836881 100644
--- a/tools/image-host.c
+++ b/tools/image-host.c
@@ -26,12 +26,8 @@
*/
#include "mkimage.h"
-#include <bootstage.h>
#include <image.h>
-#include <sha1.h>
-#include <time.h>
-#include <u-boot/crc.h>
-#include <u-boot/md5.h>
+#include <version.h>
/**
* fit_set_hash_value - set hash value in requested has node
@@ -108,9 +104,165 @@ static int fit_image_process_hash(void *fit, const char *image_name,
}
/**
- * fit_image_add_verification_data() - calculate/set hash data for image node
+ * fit_image_write_sig() - write the signature to a FIT
*
- * This adds hash values for a component image node.
+ * This writes the signature and signer data to the FIT.
+ *
+ * @fit: pointer to the FIT format image header
+ * @noffset: hash node offset
+ * @value: signature value to be set
+ * @value_len: signature value length
+ * @comment: Text comment to write (NULL for none)
+ *
+ * returns
+ * 0, on success
+ * -FDT_ERR_..., on failure
+ */
+static int fit_image_write_sig(void *fit, int noffset, uint8_t *value,
+ int value_len, const char *comment, const char *region_prop,
+ int region_proplen)
+{
+ int string_size;
+ int ret;
+
+ /*
+ * Get the current string size, before we update the FIT and add
+ * more
+ */
+ string_size = fdt_size_dt_strings(fit);
+
+ ret = fdt_setprop(fit, noffset, FIT_VALUE_PROP, value, value_len);
+ if (!ret) {
+ ret = fdt_setprop_string(fit, noffset, "signer-name",
+ "mkimage");
+ }
+ if (!ret) {
+ ret = fdt_setprop_string(fit, noffset, "signer-version",
+ PLAIN_VERSION);
+ }
+ if (comment && !ret)
+ ret = fdt_setprop_string(fit, noffset, "comment", comment);
+ if (!ret)
+ ret = fit_set_timestamp(fit, noffset, time(NULL));
+ if (region_prop && !ret) {
+ uint32_t strdata[2];
+
+ ret = fdt_setprop(fit, noffset, "hashed-nodes",
+ region_prop, region_proplen);
+ strdata[0] = 0;
+ strdata[1] = cpu_to_fdt32(string_size);
+ if (!ret) {
+ ret = fdt_setprop(fit, noffset, "hashed-strings",
+ strdata, sizeof(strdata));
+ }
+ }
+
+ return ret;
+}
+
+static int fit_image_setup_sig(struct image_sign_info *info,
+ const char *keydir, void *fit, const char *image_name,
+ int noffset, const char *require_keys)
+{
+ const char *node_name;
+ char *algo_name;
+
+ node_name = fit_get_name(fit, noffset, NULL);
+ if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
+ printf("Can't get algo property for '%s' signature node in '%s' image node\n",
+ node_name, image_name);
+ return -1;
+ }
+
+ memset(info, '\0', sizeof(*info));
+ info->keydir = keydir;
+ info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
+ info->fit = fit;
+ info->node_offset = noffset;
+ info->algo = image_get_sig_algo(algo_name);
+ info->require_keys = require_keys;
+ if (!info->algo) {
+ printf("Unsupported signature algorithm (%s) for '%s' signature node in '%s' image node\n",
+ algo_name, node_name, image_name);
+ return -1;
+ }
+
+ return 0;
+}
+
+/**
+ * fit_image_process_sig- Process a single subnode of the images/ node
+ *
+ * Check each subnode and process accordingly. For signature nodes we
+ * generate a signed hash of the supplised data and store it in the node.
+ *
+ * @keydir: Directory containing keys to use for signing
+ * @keydest: Destination FDT blob to write public keys into
+ * @fit: pointer to the FIT format image header
+ * @image_name: name of image being processes (used to display errors)
+ * @noffset: subnode offset
+ * @data: data to process
+ * @size: size of data in bytes
+ * @comment: Comment to add to signature nodes
+ * @require_keys: Mark all keys as 'required'
+ * @return 0 if ok, -1 on error
+ */
+static int fit_image_process_sig(const char *keydir, void *keydest,
+ void *fit, const char *image_name,
+ int noffset, const void *data, size_t size,
+ const char *comment, int require_keys)
+{
+ struct image_sign_info info;
+ struct image_region region;
+ const char *node_name;
+ uint8_t *value;
+ uint value_len;
+ int ret;
+
+ if (fit_image_setup_sig(&info, keydir, fit, image_name, noffset,
+ require_keys ? "image" : NULL))
+ return -1;
+
+ node_name = fit_get_name(fit, noffset, NULL);
+ region.data = data;
+ region.size = size;
+ ret = info.algo->sign(&info, ®ion, 1, &value, &value_len);
+ if (ret) {
+ printf("Failed to sign '%s' signature node in '%s' image node: %d\n",
+ node_name, image_name, ret);
+
+ /* We allow keys to be missing */
+ if (ret == -ENOENT)
+ return 0;
+ return -1;
+ }
+
+ ret = fit_image_write_sig(fit, noffset, value, value_len, comment,
+ NULL, 0);
+ if (ret) {
+ printf("Can't write signature for '%s' signature node in '%s' image node: %s\n",
+ node_name, image_name, fdt_strerror(ret));
+ return -1;
+ }
+ free(value);
+
+ /* Get keyname again, as FDT has changed and invalidated our pointer */
+ info.keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
+
+ /* Write the public key into the supplied FDT file */
+ if (keydest && info.algo->add_verify_data(&info, keydest)) {
+ printf("Failed to add verification data for '%s' signature node in '%s' image node\n",
+ node_name, image_name);
+ return -1;
+ }
+
+ return 0;
+}
+
+/**
+ * fit_image_add_verification_data() - calculate/set verig. data for image node
+ *
+ * This adds hash and signature values for an component image node.
*
* All existing hash subnodes are checked, if algorithm property is set to
* one of the supported hash algorithms, hash value is computed and
@@ -133,11 +285,17 @@ static int fit_image_process_hash(void *fit, const char *image_name,
*
* For signature details, please see doc/uImage.FIT/signature.txt
*
+ * @keydir Directory containing *.key and *.crt files (or NULL)
+ * @keydest FDT Blob to write public keys into (NULL if none)
* @fit: Pointer to the FIT format image header
* @image_noffset: Requested component image node
+ * @comment: Comment to add to signature nodes
+ * @require_keys: Mark all keys as 'required'
* @return: 0 on success, <0 on failure
*/
-int fit_image_add_verification_data(void *fit, int image_noffset)
+int fit_image_add_verification_data(const char *keydir, void *keydest,
+ void *fit, int image_noffset, const char *comment,
+ int require_keys)
{
const char *image_name;
const void *data;
@@ -171,6 +329,12 @@ int fit_image_add_verification_data(void *fit, int image_noffset)
strlen(FIT_HASH_NODENAME))) {
ret = fit_image_process_hash(fit, image_name, noffset,
data, size);
+ } else if (IMAGE_ENABLE_SIGN && keydir &&
+ !strncmp(node_name, FIT_SIG_NODENAME,
+ strlen(FIT_SIG_NODENAME))) {
+ ret = fit_image_process_sig(keydir, keydest,
+ fit, image_name, noffset, data, size,
+ comment, require_keys);
}
if (ret)
return -1;
@@ -179,7 +343,8 @@ int fit_image_add_verification_data(void *fit, int image_noffset)
return 0;
}
-int fit_add_verification_data(void *fit)
+int fit_add_verification_data(const char *keydir, void *keydest, void *fit,
+ const char *comment, int require_keys)
{
int images_noffset;
int noffset;
@@ -204,7 +369,8 @@ int fit_add_verification_data(void *fit)
* Direct child node of the images parent node,
* i.e. component image node.
*/
- ret = fit_image_add_verification_data(fit, noffset);
+ ret = fit_image_add_verification_data(keydir, keydest,
+ fit, noffset, comment, require_keys);
if (ret)
return ret;
}
--
1.8.1.3
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