From 05cc0054d8d3e07bd4ff62aab247bfa6ac070355 Mon Sep 17 00:00:00 2001
From: Vadim Vetrov <vetrovvd@gmail.com>
Date: Sat, 12 Oct 2024 16:55:27 +0300
Subject: [PATCH] Fix getrandom on older versions

---
 args.h  |  4 ----
 tls.c   | 22 ++++++++++++++++++----
 types.h |  6 ++++++
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/args.h b/args.h
index 0c3d52e..98d65cf 100644
--- a/args.h
+++ b/args.h
@@ -1,6 +1,3 @@
-#include "utils.h"
-#include "tls.h"
-
 #ifndef ARGS_H
 #define ARGS_H
 
@@ -11,5 +8,4 @@ int parse_args(int argc, char *argv[]);
 /* Prints starting messages */
 void print_welcome();
 
-
 #endif /* ARGS_H */
diff --git a/tls.c b/tls.c
index b1e6099..6b13c3a 100644
--- a/tls.c
+++ b/tls.c
@@ -5,8 +5,8 @@
 #include "utils.h"
 
 #ifndef KERNEL_SPACE
-#include <stdlib.h>
-#include <sys/random.h>
+#include <fcntl.h>
+#include <unistd.h>
 #endif
 
 #define TLS_CONTENT_TYPE_HANDSHAKE 0x16
@@ -274,6 +274,8 @@ int gen_fake_sni(struct fake_type type,
 		const struct tcphdr *tcph, uint32_t tcph_len,
 		uint8_t *buf, uint32_t *buflen) {
 	uint32_t data_len = type.fake_len;
+	int ret;
+
 	if (type.type == FAKE_PAYLOAD_RANDOM && data_len == 0) {
 		data_len = (uint32_t)randint() % 1200;
 	}
@@ -317,9 +319,21 @@ int gen_fake_sni(struct fake_type type,
 		default: // FAKE_PAYLOAD_RANDOM
 #ifdef KERNEL_SPACE
 			get_random_bytes(bfdptr, data_len);
-#else
+#else /* KERNEL_SPACE */
+#if _NO_GETRANDOM
+			ret = open("/dev/urandom", O_RDONLY);
+			if (ret < 0) {
+				lgerror("Unable to open /dev/urandom", ret);
+				return ret;
+			}
+			
+			read(ret, bfdptr, data_len);
+			close(ret);
+			
+#else /* _NO_GETRANDOM */
 			getrandom(bfdptr, data_len, 0);
-#endif
+#endif /* _NO_GETRANDOM */
+#endif /* KERNEL_SPACE */
 	}
 
 	if (ipxv == IP4VERSION) {
diff --git a/types.h b/types.h
index 39f33cf..ab63f61 100644
--- a/types.h
+++ b/types.h
@@ -14,7 +14,13 @@
 #include <stdint.h> // IWYU pragma: export
 #include <string.h> // IWYU pragma: export
 #include <stdlib.h> // IWYU pragma: export
+
+
+#define _NO_GETRANDOM ((__GLIBC__ <= 2 && __GLIBC_MINOR__ < 25))
+
+#if !_NO_GETRANDOM
 #include <sys/random.h> // IWYU pragma: export
+#endif
 
 #endif /* SPACES */