[PATCH v4 10/16] crypto: add public_key functions
Ahmad Fatoum
a.fatoum at pengutronix.de
Fri Sep 27 01:20:36 PDT 2024
On 13.09.24 09:59, Sascha Hauer wrote:
> Now that we have a struct public_key as a general container for keys
> create and use functions making use of it. Move the list from struct
> rsa_public_key to struct public_key, add public_key_verify() and use
> it instead of rsa_verify(), move key_name_hint to struct public_key.
>
> With this we do not need to bother the FIT image code when adding
> support for ECDSA keys.
>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
> common/image-fit.c | 20 ++++----
> crypto/public-keys.c | 92 ++++++++++++++++++++++++++++++-------
> crypto/rsa.c | 74 +++++++++--------------------
> include/crypto/public_key.h | 15 ++++++
> include/rsa.h | 16 +------
> scripts/keytoc.c | 3 +-
> 6 files changed, 126 insertions(+), 94 deletions(-)
>
> diff --git a/common/image-fit.c b/common/image-fit.c
> index 4a69049abc..c5d2196bda 100644
> --- a/common/image-fit.c
> +++ b/common/image-fit.c
> @@ -20,7 +20,7 @@
> #include <errno.h>
> #include <linux/err.h>
> #include <stringlist.h>
> -#include <rsa.h>
> +#include <crypto/public_key.h>
> #include <uncompress.h>
> #include <image-fit.h>
>
> @@ -253,10 +253,10 @@ static struct digest *fit_alloc_digest(struct device_node *sig_node,
> return digest;
> }
>
> -static int fit_check_rsa_signature(struct device_node *sig_node,
> - enum hash_algo algo, void *hash)
> +static int fit_check_signature(struct device_node *sig_node,
> + enum hash_algo algo, void *hash)
> {
> - const struct rsa_public_key *key;
> + const struct public_key *key;
> const char *key_name = NULL;
> int sig_len;
> const char *sig_value;
> @@ -270,19 +270,19 @@ static int fit_check_rsa_signature(struct device_node *sig_node,
>
> of_property_read_string(sig_node, "key-name-hint", &key_name);
> if (key_name) {
> - key = rsa_get_key(key_name);
> + key = public_key_get(key_name);
> if (key) {
> - ret = rsa_verify(key, sig_value, sig_len, hash, algo);
> + ret = public_key_verify(key, sig_value, sig_len, hash, algo);
> if (!ret)
> goto ok;
> }
> }
>
> - for_each_rsa_key(key) {
> + for_each_public_key(key) {
> if (key_name && !strcmp(key->key_name_hint, key_name))
> continue;
>
> - ret = rsa_verify(key, sig_value, sig_len, hash, algo);
> + ret = public_key_verify(key, sig_value, sig_len, hash, algo);
> if (!ret)
> goto ok;
> }
> @@ -341,7 +341,7 @@ static int fit_verify_signature(struct device_node *sig_node, const void *fit)
> hash = xzalloc(digest_length(digest));
> digest_final(digest, hash);
>
> - ret = fit_check_rsa_signature(sig_node, algo, hash);
> + ret = fit_check_signature(sig_node, algo, hash);
> if (ret)
> goto out_free_hash;
>
> @@ -464,7 +464,7 @@ static int fit_image_verify_signature(struct fit_handle *handle,
> hash = xzalloc(digest_length(digest));
> digest_final(digest, hash);
>
> - ret = fit_check_rsa_signature(sig_node, algo, hash);
> + ret = fit_check_signature(sig_node, algo, hash);
>
> free(hash);
>
> diff --git a/crypto/public-keys.c b/crypto/public-keys.c
> index a3ef3bafc8..36c308908d 100644
> --- a/crypto/public-keys.c
> +++ b/crypto/public-keys.c
> @@ -2,31 +2,91 @@
> #include <crypto/public_key.h>
> #include <rsa.h>
>
> +static LIST_HEAD(public_keys);
> +
> +const struct public_key *public_key_next(const struct public_key *prev)
> +{
> + prev = list_prepare_entry(prev, &public_keys, list);
> + list_for_each_entry_continue(prev, &public_keys, list)
> + return prev;
> +
> + return NULL;
> +}
> +
> +const struct public_key *public_key_get(const char *name)
> +{
> + const struct public_key *key;
> +
> + list_for_each_entry(key, &public_keys, list) {
> + if (!strcmp(key->key_name_hint, name))
> + return key;
> + }
> +
> + return NULL;
> +}
> +
> +int public_key_add(struct public_key *key)
> +{
> + if (public_key_get(key->key_name_hint))
> + return -EEXIST;
> +
> + list_add_tail(&key->list, &public_keys);
> +
> + return 0;
> +}
> +
> +static struct public_key *public_key_dup(const struct public_key *key)
> +{
> + struct public_key *k = xzalloc(sizeof(*k));
> +
> + k->type = key->type;
> + if (key->key_name_hint)
> + k->key_name_hint = xstrdup(key->key_name_hint);
> +
> + switch (key->type) {
> + case PUBLIC_KEY_TYPE_RSA:
> + k->rsa = rsa_key_dup(key->rsa);
> + if (!k->rsa)
> + goto err;
> + break;
> + default:
> + goto err;
> + }
> +
> + return k;
> +err:
> + free(k->key_name_hint);
> + free(k);
> +
> + return NULL;
> +}
> +
> +int public_key_verify(const struct public_key *key, const uint8_t *sig,
> + const uint32_t sig_len, const uint8_t *hash,
> + enum hash_algo algo)
> +{
> + switch (key->type) {
> + case PUBLIC_KEY_TYPE_RSA:
> + return rsa_verify(key->rsa, sig, sig_len, hash, algo);
> + }
> +
> + return -ENOKEY;
> +}
> +
> extern const struct public_key * const __public_keys_start;
> extern const struct public_key * const __public_keys_end;
>
> static int init_public_keys(void)
> {
> const struct public_key * const *iter;
> - int ret;
>
> for (iter = &__public_keys_start; iter != &__public_keys_end; iter++) {
> - struct rsa_public_key *rsa_key;
> -
> - switch ((*iter)->type) {
> - case PUBLIC_KEY_TYPE_RSA:
> - rsa_key = rsa_key_dup((*iter)->rsa);
> - if (!rsa_key)
> - continue;
> -
> - ret = rsa_key_add(rsa_key);
> - if (ret)
> - pr_err("Cannot add rsa key: %pe\n", ERR_PTR(ret));
> - break;
> - default:
> - pr_err("Ignoring unknown key type %u\n", (*iter)->type);
> - }
> + struct public_key *key = public_key_dup(*iter);
> +
> + if (!key)
> + continue;
>
> + public_key_add(key);
> }
>
> return 0;
> diff --git a/crypto/rsa.c b/crypto/rsa.c
> index 8eab07beed..969dbfb32b 100644
> --- a/crypto/rsa.c
> +++ b/crypto/rsa.c
> @@ -15,6 +15,7 @@
> #include <asm/byteorder.h>
> #include <errno.h>
> #include <rsa.h>
> +#include <crypto/public_key.h>
> #include <asm/unaligned.h>
>
> #define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby)))
> @@ -380,105 +381,74 @@ static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len)
> dst[i] = fdt32_to_cpu(src[len - 1 - i]);
> }
>
> -struct rsa_public_key *rsa_of_read_key(struct device_node *node)
> +struct public_key *rsa_of_read_key(struct device_node *node)
> {
> const void *modulus, *rr;
> const uint64_t *public_exponent;
> int length;
> - struct rsa_public_key *key;
> + struct public_key *key;
> + struct rsa_public_key *rsa;
> int err;
>
> if (strncmp(node->name, "key-", 4))
> return ERR_PTR(-EINVAL);
>
> key = xzalloc(sizeof(*key));
> + rsa = key->rsa = xzalloc(sizeof(*rsa));
>
> key->key_name_hint = xstrdup(node->name + 4);
>
> - of_property_read_u32(node, "rsa,num-bits", &key->len);
> - of_property_read_u32(node, "rsa,n0-inverse", &key->n0inv);
> + of_property_read_u32(node, "rsa,num-bits", &rsa->len);
> + of_property_read_u32(node, "rsa,n0-inverse", &rsa->n0inv);
>
> public_exponent = of_get_property(node, "rsa,exponent", &length);
> if (!public_exponent || length < sizeof(*public_exponent))
> - key->exponent = RSA_DEFAULT_PUBEXP;
> + rsa->exponent = RSA_DEFAULT_PUBEXP;
> else
> - key->exponent = fdt64_to_cpu(*public_exponent);
> + rsa->exponent = fdt64_to_cpu(*public_exponent);
>
> modulus = of_get_property(node, "rsa,modulus", NULL);
> rr = of_get_property(node, "rsa,r-squared", NULL);
>
> - if (!key->len || !modulus || !rr) {
> + if (!rsa->len || !modulus || !rr) {
> pr_debug("%s: Missing RSA key info", __func__);
> err = -EFAULT;
> goto out;
> }
>
> /* Sanity check for stack size */
> - if (key->len > RSA_MAX_KEY_BITS || key->len < RSA_MIN_KEY_BITS) {
> + if (rsa->len > RSA_MAX_KEY_BITS || rsa->len < RSA_MIN_KEY_BITS) {
> pr_debug("RSA key bits %u outside allowed range %d..%d\n",
> - key->len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);
> + rsa->len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);
> err = -EFAULT;
> goto out;
> }
>
> - key->len /= sizeof(uint32_t) * 8;
> + rsa->len /= sizeof(uint32_t) * 8;
>
> - key->modulus = xzalloc(RSA_MAX_KEY_BITS / 8);
> - key->rr = xzalloc(RSA_MAX_KEY_BITS / 8);
> + rsa->modulus = xzalloc(RSA_MAX_KEY_BITS / 8);
> + rsa->rr = xzalloc(RSA_MAX_KEY_BITS / 8);
>
> - rsa_convert_big_endian(key->modulus, modulus, key->len);
> - rsa_convert_big_endian(key->rr, rr, key->len);
> + rsa_convert_big_endian(rsa->modulus, modulus, rsa->len);
> + rsa_convert_big_endian(rsa->rr, rr, rsa->len);
>
> err = 0;
> out:
> - if (err)
> + if (err) {
> free(key);
> + free(rsa);
> + }
>
> return err ? ERR_PTR(err) : key;
> }
>
> void rsa_key_free(struct rsa_public_key *key)
> {
> - list_del(&key->list);
> -
> free(key->modulus);
> free(key->rr);
> free(key);
> }
>
> -static LIST_HEAD(rsa_keys);
> -
> -const struct rsa_public_key *rsa_key_next(const struct rsa_public_key *prev)
> -{
> - prev = list_prepare_entry(prev, &rsa_keys, list);
> - list_for_each_entry_continue(prev, &rsa_keys, list)
> - return prev;
> -
> - return NULL;
> -}
> -
> -const struct rsa_public_key *rsa_get_key(const char *name)
> -{
> - const struct rsa_public_key *key;
> -
> - list_for_each_entry(key, &rsa_keys, list) {
> - if (!strcmp(key->key_name_hint, name))
> - return key;
> - }
> -
> - return NULL;
> -}
> -
> -int rsa_key_add(struct rsa_public_key *key)
> -{
> - if (rsa_get_key(key->key_name_hint))
> - return -EEXIST;
> -
> - list_add_tail(&key->list, &rsa_keys);
> -
> - return 0;
> -}
> -
> struct rsa_public_key *rsa_key_dup(const struct rsa_public_key *key)
> {
> struct rsa_public_key *new;
> @@ -493,7 +463,7 @@ struct rsa_public_key *rsa_key_dup(const struct rsa_public_key *key)
> static void rsa_init_keys_of(void)
> {
> struct device_node *sigs, *sig;
> - struct rsa_public_key *key;
> + struct public_key *key;
> int ret;
>
> if (!IS_ENABLED(CONFIG_OFTREE))
> @@ -511,7 +481,7 @@ static void rsa_init_keys_of(void)
> continue;
> }
>
> - ret = rsa_key_add(key);
> + ret = public_key_add(key);
> if (ret)
> pr_err("Cannot add rsa key %s: %s\n",
> key->key_name_hint, strerror(-ret));
> diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
> index 83e8401aed..1b91063042 100644
> --- a/include/crypto/public_key.h
> +++ b/include/crypto/public_key.h
> @@ -1,6 +1,8 @@
> #ifndef __CRYPTO_PUBLIC_KEY_H
> #define __CRYPTO_PUBLIC_KEY_H
>
> +#include <digest.h>
> +
> struct rsa_public_key;
> struct ecdsa_public_key;
>
> @@ -10,6 +12,8 @@ enum pulic_key_type {
>
> struct public_key {
> enum pulic_key_type type;
> + struct list_head list;
> + char *key_name_hint;
>
> union {
> struct rsa_public_key *rsa;
> @@ -17,4 +21,15 @@ struct public_key {
> };
> };
>
> +int public_key_add(struct public_key *key);
> +const struct public_key *public_key_get(const char *name);
> +const struct public_key *public_key_next(const struct public_key *prev);
> +
> +#define for_each_public_key(key) \
> + for (key = public_key_next(NULL); key; key = public_key_next(key))
> +
> +int public_key_verify(const struct public_key *key, const uint8_t *sig,
> + const uint32_t sig_len, const uint8_t *hash,
> + enum hash_algo algo);
> +
> #endif /* __CRYPTO_PUBLIC_KEY_H */
> diff --git a/include/rsa.h b/include/rsa.h
> index ecb2f42957..ef03a925b8 100644
> --- a/include/rsa.h
> +++ b/include/rsa.h
> @@ -29,8 +29,6 @@ struct rsa_public_key {
> uint32_t *modulus; /* modulus as little endian array */
> uint32_t *rr; /* R^2 as little endian array */
> uint64_t exponent; /* public exponent */
> - char *key_name_hint;
> - struct list_head list;
> };
>
> /**
> @@ -54,24 +52,12 @@ int rsa_verify(const struct rsa_public_key *key, const uint8_t *sig,
>
> struct device_node;
>
> -struct rsa_public_key *rsa_of_read_key(struct device_node *node);
> +struct public_key *rsa_of_read_key(struct device_node *node);
> void rsa_key_free(struct rsa_public_key *key);
> -const struct rsa_public_key *rsa_get_key(const char *name);
> -
> -const struct rsa_public_key *rsa_key_next(const struct rsa_public_key *prev);
> -
> -#define for_each_rsa_key(key) \
> - for (key = rsa_key_next(NULL); key; key = rsa_key_next(key))
>
> #ifdef CONFIG_CRYPTO_RSA
> -int rsa_key_add(struct rsa_public_key *key);
> struct rsa_public_key *rsa_key_dup(const struct rsa_public_key *key);
> #else
> -static inline int rsa_key_add(struct rsa_public_key *key)
> -{
> - return -ENOSYS;
> -}
> -
> static inline struct rsa_public_key *rsa_key_dup(const struct rsa_public_key *key);
> {
> return NULL;
> diff --git a/scripts/keytoc.c b/scripts/keytoc.c
> index e66c5989bf..8b29118c95 100644
> --- a/scripts/keytoc.c
> +++ b/scripts/keytoc.c
> @@ -491,6 +491,7 @@ static int gen_key_ecdsa(EVP_PKEY *key, const char *key_name, const char *key_na
> if (!standalone) {
> fprintf(outfilep, "\nstatic struct public_key %s_public_key = {\n", key_name_c);
> fprintf(outfilep, "\t.type = PUBLIC_KEY_TYPE_ECDSA,\n");
> + fprintf(outfilep, "\t.key_name_hint = \"%s\",\n", key_name);
> fprintf(outfilep, "\t.ecdsa = &%s,\n", key_name_c);
> fprintf(outfilep, "};");
> fprintf(outfilep, "\nstruct public_key *%s_ecdsa_p __attribute__((section(\".public_keys.rodata.%s\"))) = &%s_public_key;\n",
> @@ -551,12 +552,12 @@ static int gen_key_rsa(EVP_PKEY *key, const char *key_name, const char *key_name
> fprintf(outfilep, "\t.modulus = %s_modulus,\n", key_name_c);
> fprintf(outfilep, "\t.rr = %s_rr,\n", key_name_c);
> fprintf(outfilep, "\t.exponent = 0x%0lx,\n", exponent);
> - fprintf(outfilep, "\t.key_name_hint = \"%s\",\n", key_name);
> fprintf(outfilep, "};\n");
>
> if (!standalone) {
> fprintf(outfilep, "\nstatic struct public_key %s_public_key = {\n", key_name_c);
> fprintf(outfilep, "\t.type = PUBLIC_KEY_TYPE_RSA,\n");
> + fprintf(outfilep, "\t.key_name_hint = \"%s\",\n", key_name);
> fprintf(outfilep, "\t.rsa = &%s,\n", key_name_c);
> fprintf(outfilep, "};");
> fprintf(outfilep, "\nstruct public_key *%sp __attribute__((section(\".public_keys.rodata.%s\"))) = &%s_public_key;\n",
--
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