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-rw-r--r--boot/image-fit-sig.c97
1 files changed, 72 insertions, 25 deletions
diff --git a/boot/image-fit-sig.c b/boot/image-fit-sig.c
index 495d7768f6..e07bacb77a 100644
--- a/boot/image-fit-sig.c
+++ b/boot/image-fit-sig.c
@@ -135,7 +135,7 @@ int fit_image_check_sig(const void *fit, int noffset, const void *data,
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)
+ const void *key_blob, int key_offset)
{
int noffset;
char *err_msg = "";
@@ -184,34 +184,34 @@ 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)
+ const void *key_blob, int *no_sigsp)
{
int verify_count = 0;
int noffset;
- int sig_node;
+ int key_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) {
+ key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
+ if (key_node < 0) {
debug("%s: No signature node found: %s\n", __func__,
- fdt_strerror(sig_node));
+ fdt_strerror(key_node));
return 0;
}
- fdt_for_each_subnode(noffset, sig_blob, sig_node) {
+ fdt_for_each_subnode(noffset, key_blob, key_node) {
const char *required;
int ret;
- required = fdt_getprop(sig_blob, noffset, FIT_KEY_REQUIRED,
+ required = fdt_getprop(key_blob, noffset, FIT_KEY_REQUIRED,
NULL);
if (!required || strcmp(required, "image"))
continue;
ret = fit_image_verify_sig(fit, image_noffset, data, size,
- sig_blob, noffset);
+ key_blob, noffset);
if (ret) {
printf("Failed to verify required signature '%s'\n",
- fit_get_name(sig_blob, noffset, NULL));
+ fit_get_name(key_blob, noffset, NULL));
return ret;
}
verify_count++;
@@ -368,8 +368,35 @@ static int fit_config_check_sig(const void *fit, int noffset,
return 0;
}
-static int fit_config_verify_sig(const void *fit, int conf_noffset,
- const void *sig_blob, int sig_offset)
+/**
+ * fit_config_verify_key() - Verify that a configuration is signed with a key
+ *
+ * Here we are looking at a particular configuration that needs verification:
+ *
+ * configurations {
+ * default = "conf-1";
+ * conf-1 {
+ * kernel = "kernel-1";
+ * fdt = "fdt-1";
+ * signature-1 {
+ * algo = "sha1,rsa2048";
+ * value = <...conf 1 signature...>;
+ * };
+ * };
+ *
+ * We must check each of the signature subnodes of conf-1. Hopefully one of them
+ * will match the key at key_offset.
+ *
+ * @fit: FIT to check
+ * @conf_noffset: Offset of the configuration node to check (e.g.
+ * /configurations/conf-1)
+ * @key_blob: Blob containing the keys to check against
+ * @key_offset: Offset of the key to check within @key_blob
+ * @return 0 if OK, -EPERM if any signatures did not verify, or the
+ * configuration node has an invalid name
+ */
+static int fit_config_verify_key(const void *fit, int conf_noffset,
+ const void *key_blob, int key_offset)
{
int noffset;
char *err_msg = "No 'signature' subnode found";
@@ -382,7 +409,7 @@ static int fit_config_verify_sig(const void *fit, int conf_noffset,
if (!strncmp(name, FIT_SIG_NODENAME,
strlen(FIT_SIG_NODENAME))) {
- ret = fit_config_check_sig(fit, noffset, sig_offset,
+ ret = fit_config_check_sig(fit, noffset, key_offset,
conf_noffset, &err_msg);
if (ret) {
puts("- ");
@@ -409,12 +436,25 @@ error:
return -EPERM;
}
-static int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
- const void *sig_blob)
+/**
+ * fit_config_verify_required_keys() - verify any required signatures for config
+ *
+ * This looks through all the signatures we expect and verifies that at least
+ * all the required ones are valid signatures for the configuration
+ *
+ * @fit: FIT to check
+ * @conf_noffset: Offset of the configuration node to check (e.g.
+ * /configurations/conf-1)
+ * @key_blob: Blob containing the keys to check against
+ * @return 0 if OK, -EPERM if any signatures did not verify, or the
+ * configuration node has an invalid name
+ */
+static int fit_config_verify_required_keys(const void *fit, int conf_noffset,
+ const void *key_blob)
{
const char *name = fit_get_name(fit, conf_noffset, NULL);
int noffset;
- int sig_node;
+ int key_node;
int verified = 0;
int reqd_sigs = 0;
bool reqd_policy_all = true;
@@ -430,38 +470,45 @@ static int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
}
/* Work out what we need to verify */
- sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
- if (sig_node < 0) {
+ key_node = fdt_subnode_offset(key_blob, 0, FIT_SIG_NODENAME);
+ if (key_node < 0) {
debug("%s: No signature node found: %s\n", __func__,
- fdt_strerror(sig_node));
+ fdt_strerror(key_node));
return 0;
}
/* Get required-mode policy property from DTB */
- reqd_mode = fdt_getprop(sig_blob, sig_node, "required-mode", NULL);
+ reqd_mode = fdt_getprop(key_blob, key_node, "required-mode", NULL);
if (reqd_mode && !strcmp(reqd_mode, "any"))
reqd_policy_all = false;
debug("%s: required-mode policy set to '%s'\n", __func__,
reqd_policy_all ? "all" : "any");
- fdt_for_each_subnode(noffset, sig_blob, sig_node) {
+ /*
+ * The algorithm here is a little convoluted due to how we want it to
+ * work. Here we work through each of the signature nodes in the
+ * public-key area. These are in the U-Boot control devicetree. Each
+ * node was created by signing a configuration, so we check if it is
+ * 'required' and if so, request that it be verified.
+ */
+ fdt_for_each_subnode(noffset, key_blob, key_node) {
const char *required;
int ret;
- required = fdt_getprop(sig_blob, noffset, FIT_KEY_REQUIRED,
+ required = fdt_getprop(key_blob, noffset, FIT_KEY_REQUIRED,
NULL);
if (!required || strcmp(required, "conf"))
continue;
reqd_sigs++;
- ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
+ ret = fit_config_verify_key(fit, conf_noffset, key_blob,
noffset);
if (ret) {
if (reqd_policy_all) {
printf("Failed to verify required signature '%s'\n",
- fit_get_name(sig_blob, noffset, NULL));
+ fit_get_name(key_blob, noffset, NULL));
return ret;
}
} else {
@@ -481,6 +528,6 @@ static int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
int fit_config_verify(const void *fit, int conf_noffset)
{
- return fit_config_verify_required_sigs(fit, conf_noffset,
+ return fit_config_verify_required_keys(fit, conf_noffset,
gd_fdt_blob());
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-02 01:28:10 +0300