rsa: add sha256-rsa2048 algorithm
based on patch from andreas@oetken.name:
http://patchwork.ozlabs.org/patch/294318/
commit message:
I currently need support for rsa-sha256 signatures in u-boot and found out that
the code for signatures is not very generic. Thus adding of different
hash-algorithms for rsa-signatures is not easy to do without copy-pasting the
rsa-code. I attached a patch for how I think it could be better and included
support for rsa-sha256. This is a fast first shot.
aditionally work:
- removed checkpatch warnings
- removed compiler warnings
- rebased against current head
Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: andreas@oetken.name
Cc: Simon Glass <sjg@chromium.org>
diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
index 164ab39..a5a96cb6 100644
--- a/lib/rsa/Makefile
+++ b/lib/rsa/Makefile
@@ -7,4 +7,4 @@
# SPDX-License-Identifier: GPL-2.0+
#
-obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o
+obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
diff --git a/lib/rsa/rsa-checksum.c b/lib/rsa/rsa-checksum.c
new file mode 100644
index 0000000..e520e1c
--- /dev/null
+++ b/lib/rsa/rsa-checksum.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2013, Andreas Oetken.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <rsa.h>
+#include <sha1.h>
+#include <sha256.h>
+#include <asm/byteorder.h>
+#include <asm/errno.h>
+#include <asm/unaligned.h>
+
+#define RSA2048_BYTES 256
+
+/* PKCS 1.5 paddings as described in the RSA PKCS#1 v2.1 standard. */
+
+const uint8_t padding_sha256_rsa2048[RSA2048_BYTES - SHA256_SUM_LEN] = {
+0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x31, 0x30,
+0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
+0x00, 0x04, 0x20
+};
+
+const uint8_t padding_sha1_rsa2048[RSA2048_BYTES - SHA1_SUM_LEN] = {
+ 0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x21, 0x30,
+ 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a,
+ 0x05, 0x00, 0x04, 0x14
+};
+
+void sha1_calculate(const struct image_region region[], int region_count,
+ uint8_t *checksum)
+{
+ sha1_context ctx;
+ uint32_t i;
+ i = 0;
+
+ sha1_starts(&ctx);
+ for (i = 0; i < region_count; i++)
+ sha1_update(&ctx, region[i].data, region[i].size);
+ sha1_finish(&ctx, checksum);
+}
+
+void sha256_calculate(const struct image_region region[], int region_count,
+ uint8_t *checksum)
+{
+ sha256_context ctx;
+ uint32_t i;
+ i = 0;
+
+ sha256_starts(&ctx);
+ for (i = 0; i < region_count; i++)
+ sha256_update(&ctx, region[i].data, region[i].size);
+ sha256_finish(&ctx, checksum);
+}
diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 549130e..0fe6e9f 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -159,8 +159,9 @@
EVP_cleanup();
}
-static int rsa_sign_with_key(RSA *rsa, const struct image_region region[],
- int region_count, uint8_t **sigp, uint *sig_size)
+static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
+ const struct image_region region[], int region_count,
+ uint8_t **sigp, uint *sig_size)
{
EVP_PKEY *key;
EVP_MD_CTX *context;
@@ -192,7 +193,7 @@
goto err_create;
}
EVP_MD_CTX_init(context);
- if (!EVP_SignInit(context, EVP_sha1())) {
+ if (!EVP_SignInit(context, checksum_algo->calculate())) {
ret = rsa_err("Signer setup failed");
goto err_sign;
}
@@ -242,7 +243,8 @@
ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
if (ret)
goto err_priv;
- ret = rsa_sign_with_key(rsa, region, region_count, sigp, sig_len);
+ ret = rsa_sign_with_key(rsa, info->algo->checksum, region,
+ region_count, sigp, sig_len);
if (ret)
goto err_sign;
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 02cc4e3..b3573a8 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -8,23 +8,11 @@
#include <fdtdec.h>
#include <rsa.h>
#include <sha1.h>
+#include <sha256.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
#include <asm/unaligned.h>
-/**
- * struct rsa_public_key - holder for a public key
- *
- * An RSA public key consists of a modulus (typically called N), the inverse
- * and R^2, where R is 2^(# key bits).
- */
-struct rsa_public_key {
- uint len; /* Length of modulus[] in number of uint32_t */
- uint32_t n0inv; /* -1 / modulus[0] mod 2^32 */
- uint32_t *modulus; /* modulus as little endian array */
- uint32_t *rr; /* R^2 as little endian array */
-};
-
#define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby)))
#define RSA2048_BYTES (2048 / 8)
@@ -36,39 +24,6 @@
/* This is the maximum signature length that we support, in bits */
#define RSA_MAX_SIG_BITS 2048
-static const uint8_t padding_sha1_rsa2048[RSA2048_BYTES - SHA1_SUM_LEN] = {
- 0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x21, 0x30,
- 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a,
- 0x05, 0x00, 0x04, 0x14
-};
-
/**
* subtract_modulus() - subtract modulus from the given value
*
@@ -209,13 +164,14 @@
}
static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig,
- const uint32_t sig_len, const uint8_t *hash)
+ const uint32_t sig_len, const uint8_t *hash,
+ struct checksum_algo *algo)
{
const uint8_t *padding;
int pad_len;
int ret;
- if (!key || !sig || !hash)
+ if (!key || !sig || !hash || !algo)
return -EIO;
if (sig_len != (key->len * sizeof(uint32_t))) {
@@ -223,6 +179,8 @@
return -EINVAL;
}
+ debug("Checksum algorithm: %s", algo->name);
+
/* Sanity check for stack size */
if (sig_len > RSA_MAX_SIG_BITS / 8) {
debug("Signature length %u exceeds maximum %d\n", sig_len,
@@ -238,9 +196,8 @@
if (ret)
return ret;
- /* Determine padding to use depending on the signature type. */
- padding = padding_sha1_rsa2048;
- pad_len = RSA2048_BYTES - SHA1_SUM_LEN;
+ padding = algo->rsa_padding;
+ pad_len = RSA2048_BYTES - algo->checksum_len;
/* Check pkcs1.5 padding bytes. */
if (memcmp(buf, padding, pad_len)) {
@@ -309,7 +266,7 @@
}
debug("key length %d\n", key.len);
- ret = rsa_verify_key(&key, sig, sig_len, hash);
+ ret = rsa_verify_key(&key, sig, sig_len, hash, info->algo->checksum);
if (ret) {
printf("%s: RSA failed to verify: %d\n", __func__, ret);
return ret;
@@ -323,12 +280,22 @@
uint8_t *sig, uint sig_len)
{
const void *blob = info->fdt_blob;
- uint8_t hash[SHA1_SUM_LEN];
+ /* Reserve memory for maximum checksum-length */
+ uint8_t hash[RSA2048_BYTES];
int ndepth, noffset;
int sig_node, node;
char name[100];
- sha1_context ctx;
- int ret, i;
+ int ret;
+
+ /*
+ * Verify that the checksum-length does not exceed the
+ * rsa-signature-length
+ */
+ if (info->algo->checksum->checksum_len > RSA2048_BYTES) {
+ debug("%s: invlaid checksum-algorithm %s for RSA2048\n",
+ __func__, info->algo->checksum->name);
+ return -EINVAL;
+ }
sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
if (sig_node < 0) {
@@ -336,10 +303,8 @@
return -ENOENT;
}
- sha1_starts(&ctx);
- for (i = 0; i < region_count; i++)
- sha1_update(&ctx, region[i].data, region[i].size);
- sha1_finish(&ctx, hash);
+ /* Calculate checksum with checksum-algorithm */
+ info->algo->checksum->calculate(region, region_count, hash);
/* See if we must use a particular key */
if (info->required_keynode != -1) {