From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [RFC v2 10/12] tools: Add support to generate RSI using SIRK
Date:   Tue,  7 Mar 2023 14:24:20 -0800
Message-Id: <20230307222422.2608483-10-luiz.dentz@gmail.com>
In-Reply-To: <20230307222422.2608483-1-luiz.dentz@gmail.com>
References: <20230307222422.2608483-1-luiz.dentz@gmail.com>
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From: Sathish Narasimman <sathish.narasimman@intel.com>

The patch helps to generate Resolvable set identifier adv data.
which can be used as ADV data during advertisement.
It will be used to identify the device as part of setmember for
Coordinated set identification profile.
Example:
$<path to advtest/>advtest -i "761FAE703ED681F0C50B34155B6434FB"
SIRK: 761FAE703ED681F0C50B34155B6434FB
  RSI:  0x71 0xcb 0xbc 0x7e 0x01 0x84
    Random: bccb71
    Hash:   84017e
---
 tools/advtest.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 78 insertions(+), 2 deletions(-)

diff --git a/tools/advtest.c b/tools/advtest.c
index de036e783325..9ef69ed5124a 100644
--- a/tools/advtest.c
+++ b/tools/advtest.c
@@ -13,6 +13,13 @@
 #include <config.h>
 #endif
 
+#include <stdlib.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
 #include <getopt.h>
 
 #include "lib/bluetooth.h"
@@ -32,6 +39,9 @@
 			"\xe1\x23\x99\xc1\xca\x9a\xc3\x31"
 #define SCAN_IRK	"\xfa\x73\x09\x11\x3f\x03\x37\x0f" \
 			"\xf4\xf9\x93\x1e\xf9\xa3\x63\xa6"
+#ifndef MIN
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+#endif
 
 static struct mgmt *mgmt;
 static uint16_t index1 = MGMT_INDEX_NONE;
@@ -43,13 +53,73 @@ static struct bt_hci *scan_dev;
 
 static void print_rpa(const uint8_t addr[6])
 {
-	printf("  Address:  %02x:%02x:%02x:%02x:%02x:%02x\n",
+	printf("  RSI:\t0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
 					addr[5], addr[4], addr[3],
 					addr[2], addr[1], addr[0]);
 	printf("    Random: %02x%02x%02x\n", addr[3], addr[4], addr[5]);
 	printf("    Hash:   %02x%02x%02x\n", addr[0], addr[1], addr[2]);
 }
 
+static size_t hex2bin(const char *hexstr, uint8_t *buf, size_t buflen)
+{
+	size_t i, len;
+
+	len = MIN((strlen(hexstr) / 2), buflen);
+	memset(buf, 0, len);
+
+	for (i = 0; i < len; i++)
+		if (sscanf(hexstr + (i * 2), "%02hhX", &buf[i]) != 1)
+			continue;
+
+
+	return len;
+}
+
+static bool get_random_bytes(void *buf, size_t num_bytes)
+{
+	ssize_t len;
+	int fd;
+
+	fd = open("/dev/urandom", O_RDONLY);
+	if (fd < 0)
+		return false;
+
+	len = read(fd, buf, num_bytes);
+
+	close(fd);
+
+	if (len < 0)
+		return false;
+
+	return true;
+}
+
+static void generate_rsi(char *val)
+{
+	uint8_t sirk[16], hash[3];
+	uint8_t  rsi[6] = {0};
+
+	hex2bin(val, sirk, sizeof(sirk));
+
+	get_random_bytes(&rsi[3], 3);
+
+	rsi[5] &= 0x3f; /* Clear 2 msb */
+	rsi[5] |= 0x40; /* Set 2nd msb */
+
+	crypto = bt_crypto_new();
+	if (!crypto) {
+		fprintf(stderr, "Failed to open crypto interface\n");
+		mainloop_exit_failure();
+		return;
+	}
+
+	bt_crypto_ah(crypto, sirk, rsi + 3, hash);
+	memcpy(rsi, hash, 3);
+
+	print_rpa(rsi);
+}
+
+
 static void scan_le_adv_report(const void *data, uint8_t size,
 							void *user_data)
 {
@@ -351,9 +421,11 @@ static void usage(void)
 	printf("\tadvtest [options]\n");
 	printf("options:\n"
 		"\t-h, --help             Show help options\n");
+	printf(" \t-i  <128bit SIRK>,     Generate RSI ADV Data\n");
 }
 
 static const struct option main_options[] = {
+	{ "hash",   no_argument,       NULL, 'i' },
 	{ "version",   no_argument,       NULL, 'v' },
 	{ "help",      no_argument,       NULL, 'h' },
 	{ }
@@ -366,11 +438,15 @@ int main(int argc ,char *argv[])
 	for (;;) {
 		int opt;
 
-		opt = getopt_long(argc, argv, "vh", main_options, NULL);
+		opt = getopt_long(argc, argv, "i:vh", main_options, NULL);
 		if (opt < 0)
 			break;
 
 		switch (opt) {
+		case 'i':
+			printf("SIRK: %s\n", optarg);
+			generate_rsi(optarg);
+			return EXIT_SUCCESS;
 		case 'v':
 			printf("%s\n", VERSION);
 			return EXIT_SUCCESS;
-- 
2.39.2