From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Tue, 27 Dec 2022 23:11:00 +0000 (+0100)
Subject: px5g-mbedtls: Use getrandom()
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d1893f1c889b991746f6546b98f009b4125d5046;p=openwrt%2Fstaging%2Fblocktrron.git

px5g-mbedtls: Use getrandom()

Instead of accessing /dev/urandom use the getrandom syscall. This way we
do not have to keep the file open all the time.
This also fixes a compile error with glibc:

--------
px5g-mbedtls.c: In function '_urandom':
px5g-mbedtls.c:48:9: error: ignoring return value of 'read' declared with attribute 'warn_unused_result' [-Werror=unused-result]
   48 |         read(urandom_fd, out, len);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
--------

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---

diff --git a/package/utils/px5g-mbedtls/px5g-mbedtls.c b/package/utils/px5g-mbedtls/px5g-mbedtls.c
index 0b72154509..4e0a73ab0a 100644
--- a/package/utils/px5g-mbedtls/px5g-mbedtls.c
+++ b/package/utils/px5g-mbedtls/px5g-mbedtls.c
@@ -20,6 +20,7 @@
  */
 
 #include <sys/types.h>
+#include <sys/random.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -31,6 +32,7 @@
 #include <stdbool.h>
 
 #include <mbedtls/bignum.h>
+#include <mbedtls/entropy.h>
 #include <mbedtls/x509_crt.h>
 #include <mbedtls/ecp.h>
 #include <mbedtls/rsa.h>
@@ -40,12 +42,16 @@
 #define PX5G_COPY "Copyright (c) 2009 Steven Barth <steven@midlink.org>"
 #define PX5G_LICENSE "Licensed under the GNU Lesser General Public License v2.1"
 
-static int urandom_fd;
 static char buf[16384];
 
 static int _urandom(void *ctx, unsigned char *out, size_t len)
 {
-	read(urandom_fd, out, len);
+	ssize_t ret;
+
+	ret = getrandom(out, len, 0);
+	if (ret < 0 || (size_t)ret != len)
+		return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+
 	return 0;
 }
 
@@ -306,8 +312,6 @@ int selfsigned(char **arg)
 
 int main(int argc, char *argv[])
 {
-	urandom_fd = open("/dev/urandom", O_RDONLY);
-
 	if (!argv[1]) {
 		//Usage
 	} else if (!strcmp(argv[1], "eckey")) {