SPDX: Convert all of our single license tags to Linux Kernel style

[platform/kernel/u-boot.git] / lib / rsa / rsa-verify.c

diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 5418f59..bc83354 100644 (file)
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (c) 2013, Google Inc.
- *
- * SPDX-License-Identifier:    GPL-2.0+
  */
 
 #ifndef USE_HOSTCC
@@ -25,6 +24,40 @@
 #define RSA_DEFAULT_PUBEXP     65537
 
 /**
+ * rsa_verify_padding() - Verify RSA message padding is valid
+ *
+ * Verify a RSA message's padding is consistent with PKCS1.5
+ * padding as described in the RSA PKCS#1 v2.1 standard.
+ *
+ * @msg:       Padded message
+ * @pad_len:   Number of expected padding bytes
+ * @algo:      Checksum algo structure having information on DER encoding etc.
+ * @return 0 on success, != 0 on failure
+ */
+static int rsa_verify_padding(const uint8_t *msg, const int pad_len,
+                             struct checksum_algo *algo)
+{
+       int ff_len;
+       int ret;
+
+       /* first byte must be 0x00 */
+       ret = *msg++;
+       /* second byte must be 0x01 */
+       ret |= *msg++ ^ 0x01;
+       /* next ff_len bytes must be 0xff */
+       ff_len = pad_len - algo->der_len - 3;
+       ret |= *msg ^ 0xff;
+       ret |= memcmp(msg, msg+1, ff_len-1);
+       msg += ff_len;
+       /* next byte must be 0x00 */
+       ret |= *msg++;
+       /* next der_len bytes must match der_prefix */
+       ret |= memcmp(msg, algo->der_prefix, algo->der_len);
+
+       return ret;
+}
+
+/**
  * rsa_verify_key() - Verify a signature against some data using RSA Key
  *
  * Verify a RSA PKCS1.5 signature against an expected hash using
@@ -34,14 +67,14 @@
  * @sig:       Signature
  * @sig_len:   Number of bytes in signature
  * @hash:      Pointer to the expected hash
- * @algo:      Checksum algo structure having information on RSA padding etc.
+ * @key_len:   Number of bytes in rsa key
+ * @algo:      Checksum algo structure having information on DER encoding etc.
  * @return 0 if verified, -ve on error
  */
 static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
                          const uint32_t sig_len, const uint8_t *hash,
-                         struct checksum_algo *algo)
+                         const uint32_t key_len, struct checksum_algo *algo)
 {
-       const uint8_t *padding;
        int pad_len;
        int ret;
 #if !defined(USE_HOSTCC)
@@ -83,11 +116,11 @@ static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
                return ret;
        }
 
-       padding = algo->rsa_padding;
-       pad_len = algo->key_len - algo->checksum_len;
+       pad_len = key_len - algo->checksum_len;
 
        /* Check pkcs1.5 padding bytes. */
-       if (memcmp(buf, padding, pad_len)) {
+       ret = rsa_verify_padding(buf, pad_len, algo);
+       if (ret) {
                debug("In RSAVerify(): Padding check failed!\n");
                return -EINVAL;
        }
@@ -149,7 +182,8 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
                return -EFAULT;
        }
 
-       ret = rsa_verify_key(&prop, sig, sig_len, hash, info->algo->checksum);
+       ret = rsa_verify_key(&prop, sig, sig_len, hash,
+                            info->crypto->key_len, info->checksum);
 
        return ret;
 }
@@ -160,7 +194,7 @@ int rsa_verify(struct image_sign_info *info,
 {
        const void *blob = info->fdt_blob;
        /* Reserve memory for maximum checksum-length */
-       uint8_t hash[info->algo->checksum->key_len];
+       uint8_t hash[info->crypto->key_len];
        int ndepth, noffset;
        int sig_node, node;
        char name[100];
@@ -170,10 +204,10 @@ int rsa_verify(struct image_sign_info *info,
         * Verify that the checksum-length does not exceed the
         * rsa-signature-length
         */
-       if (info->algo->checksum->checksum_len >
-           info->algo->checksum->key_len) {
+       if (info->checksum->checksum_len >
+           info->crypto->key_len) {
                debug("%s: invlaid checksum-algorithm %s for %s\n",
-                     __func__, info->algo->checksum->name, info->algo->name);
+                     __func__, info->checksum->name, info->crypto->name);
                return -EINVAL;
        }
 
@@ -184,7 +218,7 @@ int rsa_verify(struct image_sign_info *info,
        }
 
        /* Calculate checksum with checksum-algorithm */
-       ret = info->algo->checksum->calculate(info->algo->checksum->name,
+       ret = info->checksum->calculate(info->checksum->name,
                                        region, region_count, hash);
        if (ret < 0) {
                debug("%s: Error in checksum calculation\n", __func__);