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authorHauke Mehrtens <hauke@hauke-m.de>2023-02-19 21:11:12 +0100
committerHauke Mehrtens <hauke@hauke-m.de>2023-02-25 18:26:14 +0100
commit498f6e268d4d2b0ad33b430f4ba1abe397d31496 (patch)
treef6f823f1a9e6ad2b41dc411ba0f2f0ce019b2f27
parent9217ab46536353c7c792951b57163063f5ec7a3b (diff)
downloadustream-ssl-master.tar.gz
ustream-mbedtls: Use getrandom() instead of /dev/urandomHEADmaster
Instead of keeping a file descriptor open just use the getrandom syscall to get random data. This is supported by musl libc, glibc and Linux for some time now. This also improves the error handling in case this function returns not as many bytes as expected. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Reviewed-by: Torsten Duwe <duwe@lst.de>
-rw-r--r--ustream-mbedtls.c25
1 files changed, 6 insertions, 19 deletions
diff --git a/ustream-mbedtls.c b/ustream-mbedtls.c
index e79e37b..7fc7874 100644
--- a/ustream-mbedtls.c
+++ b/ustream-mbedtls.c
@@ -17,6 +17,7 @@
*/
#include <sys/types.h>
+#include <sys/random.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
@@ -25,8 +26,6 @@
#include "ustream-ssl.h"
#include "ustream-internal.h"
-static int urandom_fd = -1;
-
static int s_ustream_read(void *ctx, unsigned char *buf, size_t len)
{
struct ustream *s = ctx;
@@ -66,21 +65,12 @@ __hidden void ustream_set_io(struct ustream_ssl_ctx *ctx, void *ssl, struct ustr
mbedtls_ssl_set_bio(ssl, conn, s_ustream_write, s_ustream_read, NULL);
}
-static bool urandom_init(void)
+static int _random(void *ctx, unsigned char *out, size_t len)
{
- if (urandom_fd > -1)
- return true;
+ ssize_t ret;
- urandom_fd = open("/dev/urandom", O_RDONLY);
- if (urandom_fd < 0)
- return false;
-
- return true;
-}
-
-static int _urandom(void *ctx, unsigned char *out, size_t len)
-{
- if (read(urandom_fd, out, len) < 0)
+ ret = getrandom(out, len, 0);
+ if (ret < 0 || (size_t)ret != len)
return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
return 0;
@@ -134,9 +124,6 @@ __ustream_ssl_context_new(bool server)
mbedtls_ssl_config *conf;
int ep;
- if (!urandom_init())
- return NULL;
-
ctx = calloc(1, sizeof(*ctx));
if (!ctx)
return NULL;
@@ -159,7 +146,7 @@ __ustream_ssl_context_new(bool server)
mbedtls_ssl_config_defaults(conf, ep, MBEDTLS_SSL_TRANSPORT_STREAM,
MBEDTLS_SSL_PRESET_DEFAULT);
- mbedtls_ssl_conf_rng(conf, _urandom, NULL);
+ mbedtls_ssl_conf_rng(conf, _random, NULL);
if (server) {
mbedtls_ssl_conf_authmode(conf, MBEDTLS_SSL_VERIFY_NONE);