rsa: let rsa_of_read_key() return a fully allocated key

Until now rsa_of_read_key() took a pointer to a key and filled the
struct rsa_public_key members with allocated values. So far we have
never freed these values. Change rsa_of_read_key() to always return
a fully allocated key and provide rsa_key_free() to free it. Let the
FIT image code free the key after usage.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 22 insertions, 4 deletions

diff --git a/crypto/rsa.c b/crypto/rsa.c
index 591d15c415..2e70c8127d 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -380,11 +380,15 @@ static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len)
 		dst[i] = fdt32_to_cpu(src[len - 1 - i]);
 }
 
-int rsa_of_read_key(struct device_node *node, struct rsa_public_key *key)
+struct rsa_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;
+	int err;
+
+	key = xzalloc(sizeof(*key));
 
 	of_property_read_u32(node, "rsa,num-bits", &key->len);
 	of_property_read_u32(node, "rsa,n0-inverse", &key->n0inv);
@@ -400,14 +404,16 @@ int rsa_of_read_key(struct device_node *node, struct rsa_public_key *key)
 
 	if (!key->len || !modulus || !rr) {
 		debug("%s: Missing RSA key info", __func__);
-		return -EFAULT;
+		err = -EFAULT;
+		goto out;
 	}
 
 	/* Sanity check for stack size */
 	if (key->len > RSA_MAX_KEY_BITS || key->len < RSA_MIN_KEY_BITS) {
 		debug("RSA key bits %u outside allowed range %d..%d\n",
 		      key->len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);
-		return -EFAULT;
+		err = -EFAULT;
+		goto out;
 	}
 
 	key->len /= sizeof(uint32_t) * 8;
@@ -418,5 +424,17 @@ int rsa_of_read_key(struct device_node *node, struct rsa_public_key *key)
 	rsa_convert_big_endian(key->modulus, modulus, key->len);
 	rsa_convert_big_endian(key->rr, rr, key->len);
 
-	return 0;
+	err = 0;
+out:
+	if (err)
+		free(key);
+
+	return err ? ERR_PTR(err) : key;
+}
+
+void rsa_key_free(struct rsa_public_key *key)
+{
+	free(key->modulus);
+	free(key->rr);
+	free(key);
 }