trng: Rename rand to trng_rand

The declaration for rand conflicts with the standard library declaration
so rename it from "rand" to "trng_rand". This has the benefit of making
it obvious when we're using the true random number generator.

For consistency, this also renames init_trng/exit_trng to
trng_init/trng_exit.

BRANCH=none
BUG=b:234181908
TEST=./util/compare_build.sh -b all -j 120
     => MATCH

Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: Ic3305a91263c45786c051eaa5b3689e7464aa0ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3712032
Reviewed-by: Bobby Casey <bobbycasey@google.com>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>

6 files changed, 36 insertions, 38 deletions

diff --git a/chip/host/trng.c b/chip/host/trng.c
index 8407aa6ea1..cb69268e34 100644
--- a/chip/host/trng.c
+++ b/chip/host/trng.c
@@ -21,17 +21,17 @@
 
 static unsigned int seed;
 
-test_mockable void init_trng(void)
+test_mockable void trng_init(void)
 {
 	seed = 0;
 	srand(seed);
 }
 
-test_mockable void exit_trng(void)
+test_mockable void trng_exit(void)
 {
 }
 
-test_mockable void rand_bytes(void *buffer, size_t len)
+test_mockable void trng_rand_bytes(void *buffer, size_t len)
 {
 	uint8_t *b, *end;
 
diff --git a/chip/stm32/trng.c b/chip/stm32/trng.c
index 48d5335c53..447ccbccad 100644
--- a/chip/stm32/trng.c
+++ b/chip/stm32/trng.c
@@ -15,7 +15,7 @@
 #include "trng.h"
 #include "util.h"
 
-uint32_t rand(void)
+uint32_t trng_rand(void)
 {
 	int tries = 300;
 	/* Wait for a valid random number */
@@ -28,10 +28,10 @@ uint32_t rand(void)
 	return STM32_RNG_DR;
 }
 
-test_mockable void rand_bytes(void *buffer, size_t len)
+test_mockable void trng_rand_bytes(void *buffer, size_t len)
 {
 	while (len) {
-		uint32_t number = rand();
+		uint32_t number = trng_rand();
 		size_t cnt = 4;
 		/* deal with the lack of alignment guarantee in the API */
 		uintptr_t align = (uintptr_t)buffer & 3;
@@ -47,7 +47,7 @@ test_mockable void rand_bytes(void *buffer, size_t len)
 	}
 }
 
-test_mockable void init_trng(void)
+test_mockable void trng_init(void)
 {
 #ifdef CHIP_FAMILY_STM32L4
 	/* Enable the 48Mhz internal RC oscillator */
@@ -84,7 +84,7 @@ test_mockable void init_trng(void)
 	STM32_RNG_CR |= STM32_RNG_CR_RNGEN;
 }
 
-test_mockable void exit_trng(void)
+test_mockable void trng_exit(void)
 {
 	STM32_RNG_CR &= ~STM32_RNG_CR_RNGEN;
 	STM32_RCC_AHB2ENR &= ~STM32_RCC_AHB2ENR_RNGEN;
@@ -107,9 +107,9 @@ static int command_rand(int argc, char **argv)
 {
 	uint8_t data[32];
 
-	init_trng();
-	rand_bytes(data, sizeof(data));
-	exit_trng();
+	trng_init();
+	trng_rand_bytes(data, sizeof(data));
+	trng_exit();
 
 	ccprintf("rand %ph\n", HEX_BUF(data, sizeof(data)));
 
@@ -130,9 +130,9 @@ static enum ec_status host_command_rand(struct host_cmd_handler_args *args)
 	if (num_rand_bytes > args->response_max)
 		return EC_RES_OVERFLOW;
 
-	init_trng();
-	rand_bytes(r->rand, num_rand_bytes);
-	exit_trng();
+	trng_init();
+	trng_rand_bytes(r->rand, num_rand_bytes);
+	trng_exit();
 
 	args->response_size = num_rand_bytes;
 
diff --git a/common/fpsensor/fpsensor.c b/common/fpsensor/fpsensor.c
index 12904c0b39..a491e1af84 100644
--- a/common/fpsensor/fpsensor.c
+++ b/common/fpsensor/fpsensor.c
@@ -472,11 +472,11 @@ static enum ec_status fp_command_frame(struct host_cmd_handler_args *args)
 		 */
 		enc_info = (void *)fp_enc_buffer;
 		enc_info->struct_version = FP_TEMPLATE_FORMAT_VERSION;
-		init_trng();
-		rand_bytes(enc_info->nonce, FP_CONTEXT_NONCE_BYTES);
-		rand_bytes(enc_info->encryption_salt,
-			   FP_CONTEXT_ENCRYPTION_SALT_BYTES);
-		exit_trng();
+		trng_init();
+		trng_rand_bytes(enc_info->nonce, FP_CONTEXT_NONCE_BYTES);
+		trng_rand_bytes(enc_info->encryption_salt,
+				FP_CONTEXT_ENCRYPTION_SALT_BYTES);
+		trng_exit();
 
 		if (fgr == template_newly_enrolled) {
 			/*
@@ -485,10 +485,10 @@ static enum ec_status fp_command_frame(struct host_cmd_handler_args *args)
 			 * value.
 			 */
 			template_newly_enrolled = FP_NO_SUCH_TEMPLATE;
-			init_trng();
-			rand_bytes(fp_positive_match_salt[fgr],
-				   FP_POSITIVE_MATCH_SALT_BYTES);
-			exit_trng();
+			trng_init();
+			trng_rand_bytes(fp_positive_match_salt[fgr],
+					FP_POSITIVE_MATCH_SALT_BYTES);
+			trng_exit();
 		}
 
 		ret = derive_encryption_key(key, enc_info->encryption_salt);
@@ -647,10 +647,10 @@ static enum ec_status fp_command_template(struct host_cmd_handler_args *args)
 		       sizeof(fp_template[0]));
 		if (template_needs_validation_value(enc_info)) {
 			CPRINTS("fgr%d: Generating positive match salt.", idx);
-			init_trng();
-			rand_bytes(positive_match_salt,
-				   FP_POSITIVE_MATCH_SALT_BYTES);
-			exit_trng();
+			trng_init();
+			trng_rand_bytes(positive_match_salt,
+					FP_POSITIVE_MATCH_SALT_BYTES);
+			trng_exit();
 		}
 		if (bytes_are_trivial(positive_match_salt,
 				      sizeof(fp_positive_match_salt[0]))) {
diff --git a/common/rollback.c b/common/rollback.c
index 984058c49a..3f9e176782 100644
--- a/common/rollback.c
+++ b/common/rollback.c
@@ -400,9 +400,9 @@ static void add_entropy_deferred(void)
 	if (add_entropy_action == ADD_ENTROPY_RESET_ASYNC)
 		repeat = ROLLBACK_REGIONS;
 
-	init_trng();
+	trng_init();
 	do {
-		rand_bytes(rand, sizeof(rand));
+		trng_rand_bytes(rand, sizeof(rand));
 		if (rollback_add_entropy(rand, sizeof(rand)) != EC_SUCCESS) {
 			add_entropy_rv = EC_RES_ERROR;
 			goto out;
@@ -411,7 +411,7 @@ static void add_entropy_deferred(void)
 
 	add_entropy_rv = EC_RES_SUCCESS;
 out:
-	exit_trng();
+	trng_exit();
 }
 DECLARE_DEFERRED(add_entropy_deferred);
 
diff --git a/include/trng.h b/include/trng.h
index cea4555b41..969366ae8e 100644
--- a/include/trng.h
+++ b/include/trng.h
@@ -14,32 +14,30 @@
  *
  * Not supported by all platforms.
  **/
-void init_trng(void);
+void trng_init(void);
 
 /**
  * Shutdown the true random number generator.
  *
- * The opposite operation of init_trng(), disable the hardware resources
+ * The opposite operation of trng_init(), disable the hardware resources
  * used by the TRNG to save power.
  *
  * Not supported by all platforms.
  **/
-void exit_trng(void);
+void trng_exit(void);
 
 /**
  * Retrieve a 32 bit random value.
  *
  * Not supported on all platforms.
  **/
-#ifndef HIDE_EC_STDLIB
-uint32_t rand(void);
-#endif
+uint32_t trng_rand(void);
 
 /**
  * Output len random bytes into buffer.
  *
  * Not supported on all platforms.
  **/
-void rand_bytes(void *buffer, size_t len);
+void trng_rand_bytes(void *buffer, size_t len);
 
 #endif /* __EC_INCLUDE_TRNG_H */
diff --git a/third_party/boringssl/common/curve25519.c b/third_party/boringssl/common/curve25519.c
index 2a7fad6509..b74d3c7d97 100644
--- a/third_party/boringssl/common/curve25519.c
+++ b/third_party/boringssl/common/curve25519.c
@@ -27,7 +27,7 @@
 
 #ifdef CONFIG_RNG
 void X25519_keypair(uint8_t out_public_value[32], uint8_t out_private_key[32]) {
-  rand_bytes(out_private_key, 32);
+  trng_rand_bytes(out_private_key, 32);
 
   /* All X25519 implementations should decode scalars correctly (see
    * https://tools.ietf.org/html/rfc7748#section-5). However, if an