From: Tedd Ho-Jeong An <tedd.an@intel.com>
Date: Wed, 8 Dec 2021 22:39:19 +0000 (-0800)
Subject: emulator: Replace random number generation function
X-Git-Tag: submit/tizen/20220313.220938~15
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=cc738fa10dae2a75037f23946e4d49705a67e2eb;p=platform%2Fupstream%2Fbluez.git

emulator: Replace random number generation function

This patch replaces the rand() function to the getrandom() syscall.

It was reported by the Coverity scan
  rand() should not be used for security-related applications, because
  linear congruential algorithms are too easy to break

Signed-off-by: Anuj Jain <anuj01.jain@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>
---

diff --git a/emulator/le.c b/emulator/le.c
index 07a44c5..f8f313f 100755
--- a/emulator/le.c
+++ b/emulator/le.c
@@ -20,6 +20,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <sys/uio.h>
+#include <sys/random.h>
 #include <time.h>
 
 #include "lib/bluetooth.h"
@@ -503,11 +504,17 @@ static void send_adv_pkt(struct bt_le *hci, uint8_t channel)
 
 static unsigned int get_adv_delay(void)
 {
+	unsigned int val;
+
 	/* The advertising delay is a pseudo-random value with a range
 	 * of 0 ms to 10 ms generated for each advertising event.
 	 */
-	srand(time(NULL));
-	return (rand() % 11);
+	if (getrandom(&val, sizeof(val), 0) < 0) {
+		/* If it fails to get the random number, use a static value */
+		val = 5;
+	}
+
+	return (val % 11);
 }
 
 static void adv_timeout_callback(int id, void *user_data)
diff --git a/emulator/phy.c b/emulator/phy.c
index 2f53d72..42e808c 100755
--- a/emulator/phy.c
+++ b/emulator/phy.c
@@ -18,6 +18,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
+#include <sys/random.h>
 #include <netinet/in.h>
 #include <netinet/ip.h>
 #include <time.h>
@@ -172,8 +173,13 @@ struct bt_phy *bt_phy_new(void)
 	mainloop_add_fd(phy->rx_fd, EPOLLIN, phy_rx_callback, phy, NULL);
 
 	if (!get_random_bytes(&phy->id, sizeof(phy->id))) {
-		srandom(time(NULL));
-		phy->id = random();
+		if (getrandom(&phy->id, sizeof(phy->id), 0) < 0) {
+			mainloop_remove_fd(phy->rx_fd);
+			close(phy->tx_fd);
+			close(phy->rx_fd);
+			free(phy);
+			return NULL;
+		}
 	}
 
 	bt_phy_send(phy, BT_PHY_PKT_NULL, NULL, 0);