From:   Tedd Ho-Jeong An <hj.tedd.an@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [BlueZ PATCH 5/5] profiles/health: Replace random number generation function
Date:   Tue,  7 Dec 2021 16:54:46 -0800
Message-Id: <20211208005446.196637-6-hj.tedd.an@gmail.com>
In-Reply-To: <20211208005446.196637-1-hj.tedd.an@gmail.com>
References: <20211208005446.196637-1-hj.tedd.an@gmail.com>
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From: Tedd Ho-Jeong An <tedd.an@intel.com>

This patch replaces the rand() function to the l_getrandom() from ELL,
which uses the getrandom() system call.

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
---
 Makefile.plugins      | 1 +
 profiles/health/hdp.c | 8 ++++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Makefile.plugins b/Makefile.plugins
index c771b2dfb..7817035c6 100644
--- a/Makefile.plugins
+++ b/Makefile.plugins
@@ -87,6 +87,7 @@ builtin_sources += profiles/health/mcap.h profiles/health/mcap.c \
 			profiles/health/hdp_manager.c \
 			profiles/health/hdp.h profiles/health/hdp.c \
 			profiles/health/hdp_util.h profiles/health/hdp_util.c
+builtin_ldadd += src/libshared-ell.la $(ell_ldadd)
 endif
 
 builtin_modules += gap
diff --git a/profiles/health/hdp.c b/profiles/health/hdp.c
index 6bc41946f..e77f963a4 100644
--- a/profiles/health/hdp.c
+++ b/profiles/health/hdp.c
@@ -16,6 +16,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <unistd.h>
+#include <ell/ell.h>
 
 #include <glib.h>
 
@@ -1484,13 +1485,12 @@ static void destroy_create_dc_data(gpointer data)
 static void *generate_echo_packet(void)
 {
 	uint8_t *buf;
-	int i;
 
 	buf = g_malloc(HDP_ECHO_LEN);
-	srand(time(NULL));
+	if (buf == NULL)
+		return NULL;
 
-	for(i = 0; i < HDP_ECHO_LEN; i++)
-		buf[i] = rand() % UINT8_MAX;
+	l_getrandom(buf, HDP_ECHO_LEN);
 
 	return buf;
 }
-- 
2.25.1