[cryptolib] Add unused result before status_t functions in P-256 headers

This commit adds the `OT_WARN_UNUSED_RESULT` macro before `status_t` functions of p256 files to protect against a caller forgetting to check and forward the error code. Signed-off-by: Moritz Wettermann <[email protected]>
lowRISC · Feb 15, 2024 · c36041b · c36041b
1 parent 6a66a71
commit c36041b
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Showing 3 changed files with 17 additions and 0 deletions.
diff --git a/sw/device/lib/crypto/impl/ecc/ecdh_p256.h b/sw/device/lib/crypto/impl/ecc/ecdh_p256.h
@@ -33,6 +33,7 @@ typedef struct ecdh_p256_shared_key {
  *
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_keypair_start(void);
 
 /**
@@ -44,6 +45,7 @@ status_t ecdh_p256_keypair_start(void);
  * @param[out] public_key Generated public key.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_keypair_finalize(p256_masked_scalar_t *private_key,
                                     p256_point_t *public_key);
 
@@ -56,6 +58,7 @@ status_t ecdh_p256_keypair_finalize(p256_masked_scalar_t *private_key,
  * @param public_key Public key (Q).
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_shared_key_start(const p256_masked_scalar_t *private_key,
                                     const p256_point_t *public_key);
 
@@ -69,6 +72,7 @@ status_t ecdh_p256_shared_key_start(const p256_masked_scalar_t *private_key,
  * @param[out] shared_key Shared secret key (x-coordinate of d*Q).
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_shared_key_finalize(ecdh_p256_shared_key_t *shared_key);
 
 /**
@@ -81,6 +85,7 @@ status_t ecdh_p256_shared_key_finalize(ecdh_p256_shared_key_t *shared_key);
  *
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_sideload_keypair_start(void);
 
 /**
@@ -91,6 +96,7 @@ status_t ecdh_p256_sideload_keypair_start(void);
  * @param[out] public_key Generated public key.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_sideload_keypair_finalize(p256_point_t *public_key);
 
 /**
@@ -104,6 +110,7 @@ status_t ecdh_p256_sideload_keypair_finalize(p256_point_t *public_key);
  * @param public_key Public key (Q).
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdh_p256_sideload_shared_key_start(const p256_point_t *public_key);
 
 #ifdef __cplusplus

diff --git a/sw/device/lib/crypto/impl/ecc/ecdsa_p256.h b/sw/device/lib/crypto/impl/ecc/ecdsa_p256.h
@@ -33,6 +33,7 @@ typedef struct ecdsa_p256_signature_t {
  *
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_keygen_start(void);
 
 /**
@@ -43,6 +44,7 @@ status_t ecdsa_p256_keygen_start(void);
  *
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_sideload_keygen_start(void);
 
 /**
@@ -54,6 +56,7 @@ status_t ecdsa_p256_sideload_keygen_start(void);
  * @param[out] public_key Generated public key.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_keygen_finalize(p256_masked_scalar_t *private_key,
                                     p256_point_t *public_key);
 
@@ -66,6 +69,7 @@ status_t ecdsa_p256_keygen_finalize(p256_masked_scalar_t *private_key,
  * @param[out] public_key Public key.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_sideload_keygen_finalize(p256_point_t *public_key);
 
 /**
@@ -77,6 +81,7 @@ status_t ecdsa_p256_sideload_keygen_finalize(p256_point_t *public_key);
  * @param private_key Secret key to sign the message with.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_sign_start(const uint32_t digest[kP256ScalarWords],
                                const p256_masked_scalar_t *private_key);
 
@@ -89,6 +94,7 @@ status_t ecdsa_p256_sign_start(const uint32_t digest[kP256ScalarWords],
  * @param digest Digest of the message to sign.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_sideload_sign_start(
     const uint32_t digest[kP256ScalarWords]);
 
@@ -102,6 +108,7 @@ status_t ecdsa_p256_sideload_sign_start(
  * @param[out] result Buffer in which to store the generated signature.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_sign_finalize(ecdsa_p256_signature_t *result);
 
 /**
@@ -116,6 +123,7 @@ status_t ecdsa_p256_sign_finalize(ecdsa_p256_signature_t *result);
  * @param public_key Key to check the signature against.
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_verify_start(const ecdsa_p256_signature_t *signature,
                                  const uint32_t digest[kP256ScalarWords],
                                  const p256_point_t *public_key);
@@ -140,6 +148,7 @@ status_t ecdsa_p256_verify_start(const ecdsa_p256_signature_t *signature,
  * otherwise)
  * @return Result of the operation (OK or error).
  */
+OT_WARN_UNUSED_RESULT
 status_t ecdsa_p256_verify_finalize(const ecdsa_p256_signature_t *signature,
                                     hardened_bool_t *result);
 

diff --git a/sw/device/lib/crypto/impl/ecc/p256_common.h b/sw/device/lib/crypto/impl/ecc/p256_common.h
@@ -101,6 +101,7 @@ typedef struct p256_point {
  * @param share1_addr DMEM address of the second share.
  * @return Result of the operation.
  */
+OT_WARN_UNUSED_RESULT
 status_t p256_masked_scalar_write(const p256_masked_scalar_t *src,
                                   const otbn_addr_t share0_addr,
                                   const otbn_addr_t share1_addr);