tools: acrn-manager: remove unsafe api sscanf

function sscanf is banned according to the security
requirements. So remove sscanf api.

Tracked-On: #1254
Signed-off-by: Tianhua Sun <tianhuax.s.sun@intel.com>
Reviewed-by: Yan, Like <like.yan@intel.com>
Reviewed-by: Tao, Yuhong <yuhong.tao@intel.com>

Author: tianhuas

tools/acrn-manager/acrn_mngr.c

@@ -408,8 +408,7 @@ static int connect_to_server(const char *name)
 	struct mngr_fd *mfd;
 	int ret;
 	DIR *dir;
-	char buf[128] = { };
-	char *s_name = NULL;
+	char *s_name = NULL, *p = NULL;
 	struct dirent *entry;
 
 	dir = opendir("/run/acrn/mngr");
@@ -419,11 +418,13 @@ static int connect_to_server(const char *name)
 	}
 
 	while ((entry = readdir(dir))) {
-		memset(buf, 0, sizeof(buf));
-		ret = sscanf(entry->d_name, "%[^.]", buf);
-		if (ret != 1)
+		p = strchr(entry->d_name, '.');
+		if (!p || p == entry->d_name)
 			continue;
-		if (!strncmp(buf, name, sizeof(buf))) {
+		else
+			ret = p - entry->d_name;
+
+		if (!strncmp(entry->d_name, name, ret)) {
 			s_name = entry->d_name;
 			break;
 		}

tools/acrn-manager/acrn_vm_ops.c

@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <string.h>
 #include <errno.h>
+#include <limits.h>
 #include <pthread.h>
 #include <dirent.h>
 #include <sys/stat.h>
@@ -82,6 +83,39 @@ static int query_state(const char *name)
 	return ack.data.state;
 }
 
+/*
+ * get vmname and pid from /run/acrn/mngr/[vmname].monitor.[pid].socket
+ */
+static inline int _get_vmname_pid(const char *src, char *p_vmname,
+		int max_len_vmname, int *pid)
+{
+	char *p = NULL;
+
+	p = strchr(src, '.');
+	/* p - src: length of the substring "vmname" in the sting "src" */
+	if (!p || p - src == 0 || p - src >= max_len_vmname)
+		return -1;
+	else
+		strncpy(p_vmname, src, p - src);
+
+	/* move the pointer to the "pid" in the string "src" */
+	if (strncmp(".monitor.", p, strlen(".monitor.")))
+		return -1;
+	else
+		p = p + strlen(".monitor.");
+
+	*pid = strtol(p, NULL, 10);
+	if ((errno == ERANGE && (*pid == LONG_MAX || *pid == LONG_MIN))
+			|| (errno != 0 && *pid == 0))
+		return -1;
+
+	p = strchr(p, '.');
+	if (!p || strncmp(".socket", p, strlen(".socket")))
+		return -1;
+
+	return 0;
+}
+
 /* find all the running DM process, which has */
 /* /run/acrn/mngr/[vmname].monitor.[pid].socket */
 static void _scan_alive_vm(void)
@@ -107,10 +141,8 @@ static void _scan_alive_vm(void)
 
 	while ((entry = readdir(dir))) {
 		memset(name, 0, sizeof(name));
-		ret =
-		    sscanf(entry->d_name, "%[^.].monitor.%d.socket", name,
-			   &pid);
-		if (ret != 2)
+		ret = _get_vmname_pid(entry->d_name, name, sizeof(name), &pid);
+		if (ret < 0)
 			continue;
 
 		if (name[sizeof(name) - 1]) {
@@ -153,6 +185,34 @@ static void _scan_alive_vm(void)
 	closedir(dir);
 }
 
+/*
+ * get vmname and suffix from src,
+ * which has [vmname].[suffix]
+ */
+static inline int _get_vmname_suffix(const char *src,
+		char *name, int max_len_name, char *suffix, int max_len_suffix)
+{
+	char *p = NULL;
+
+	p = strchr(src, '.');
+	/* p - src: length of the substring vmname in the string src*/
+	if (!p || p - src == 0)
+		return -1;
+
+	strncpy(name, src, p - src);
+	if (p - src >= max_len_name) {
+		pdebug();
+		/* truncate name and go a head */
+		name[max_len_name - 1] = '\0';
+	}
+
+	strncpy(suffix, p + 1, max_len_suffix);
+	if (strncmp(suffix, "sh", strlen("sh")))
+		return -1;
+
+	return 0;
+}
+
 static void _scan_added_vm(void)
 {
 	DIR *dir;
@@ -181,27 +241,17 @@ static void _scan_added_vm(void)
 	}
 
 	while ((entry = readdir(dir))) {
-		memset(name, 0, sizeof(name));
-		memset(suffix, 0, sizeof(suffix));
-
 		ret = strnlen(entry->d_name, sizeof(entry->d_name));
 		if (ret >= sizeof(name)) {
 			pdebug();
 			continue;
 		}
 
-		ret = sscanf(entry->d_name, "%[^.].%s", name, suffix);
-
-		if (ret != 2)
-			continue;
-
-		if (name[sizeof(name) - 1]) {
-			pdebug();
-			/* truncate name and go a head */
-			name[sizeof(name) - 1] = 0;
-		}
-
-		if (strncmp(suffix, "sh", sizeof("sh")))
+		memset(name, 0, sizeof(name));
+		memset(suffix, 0, sizeof(suffix));
+		ret = _get_vmname_suffix(entry->d_name,
+				name, sizeof(name), suffix, sizeof(suffix));
+		if (ret < 0)
 			continue;
 
 		vm = vmmngr_find(name);

tools/acrn-manager/acrnctl.c

@@ -134,6 +134,33 @@ static int write_tmp_file(int fd, int n, char *word[])
 	return 0;
 }
 
+/*
+ * get vmname from the string src, and src
+ * format is "acrnctl: [vmname]"
+ */
+static inline int _get_vmname(const char *src, char *vmname, int max_len_vmname)
+{
+	const char *vmname_p = NULL;
+
+	if (!strncmp("acrnctl: ", src, strlen("acrnctl: "))) {
+		vmname_p = src + strlen("acrnctl: ");
+
+		memset(vmname, 0, max_len_vmname);
+		strncpy(vmname, vmname_p, max_len_vmname);
+		if(vmname[max_len_vmname - 1]) {
+			/* vmname is truncated */
+			printf("get vmname failed, vmname is truncated\n");
+			return -1;
+		}
+	} else {
+		/* the prefix of the string "src" isn't "acrnctl: " */
+		printf("can't found prefix 'acrnctl: '\n");
+		return -1;
+	}
+
+	return 0;
+}
+
 #define MAX_FILE_SIZE   (4096 * 4)
 #define FILE_NAME_LENGTH	128
 
@@ -150,7 +177,7 @@ static int acrnctl_do_add(int argc, char *argv[])
 	char fname[FILE_NAME_LENGTH + sizeof(TMP_FILE_SUFFIX)];
 	char cmd[128];
 	char args[128];
-	int p, i;
+	int p, i, len_cmd_out = 0;
 	char cmd_out[256];
 	char vmname[128];
 	size_t len = sizeof(cmd_out);
@@ -253,7 +280,6 @@ static int acrnctl_do_add(int argc, char *argv[])
 	}
 	system(cmd);
 
-	memset(vmname, 0, sizeof(vmname));
 	if (snprintf(cmd, sizeof(cmd), "bash %s%s >./%s.result", argv[1],
 			args, argv[1]) >= sizeof(cmd)) {
 		printf("ERROR: cmd is truncated\n");
@@ -270,14 +296,18 @@ static int acrnctl_do_add(int argc, char *argv[])
 		ret = -1;
 		goto get_vmname;
 	}
-	ret = shell_cmd(cmd, cmd_out, sizeof(cmd_out));
-	if (ret < 0)
+	len_cmd_out = shell_cmd(cmd, cmd_out, sizeof(cmd_out));
+	if (len_cmd_out < 0) {
+		ret = len_cmd_out;
 		goto get_vmname;
+	}
 
-	ret = sscanf(cmd_out, "acrnctl: %s", vmname);
-	if (ret != 1) {
-		ret = -1;
+	if(cmd_out[len_cmd_out - 1] == '\n')
+		cmd_out[len_cmd_out - 1] = '\0';
 
+	ret = _get_vmname(cmd_out, vmname, sizeof(vmname));
+	if (ret < 0) {
+		/* failed to get vmname */
 		if (snprintf(cmd, sizeof(cmd), "cat ./%s.result", argv[1]) >= sizeof(cmd)) {
 			printf("ERROR: cmd is truncated\n");
 			goto get_vmname;
@@ -538,7 +568,7 @@ static int acrnctl_do_resume(int argc, char *argv[])
 	}
 
 	if (argc == 3) {
-		sscanf(argv[2], "%x", &reason);
+		reason = strtoul(argv[2], NULL, 16);
 		reason = (reason & (0xff << 24)) ? 0 : reason;
 	} else
 		printf("No wake up reason, use 0x%x\n", reason);

tools/acrn-manager/acrnd.c

@@ -153,8 +153,7 @@ static int load_timer_list(void)
 	struct work_arg arg = {};
 	time_t expire, current;
 	char l[256];
-	char s1[16], s2[64];	/* vmname & expire */
-	int ret = 0;
+	int i, ret = 0;
 
 	pthread_mutex_lock(&timer_file_mutex);
 
@@ -173,20 +172,23 @@ static int load_timer_list(void)
 			continue;
 		}
 
-		memset(s1, 0, 16);
-		memset(s2, 0, 64);
-
-		sscanf(l, "%s\t%s", s1, s2);
+		/* get vmname from the string "l", which has "[vmname]\t[expire]" */
+		for (i = 0; i < sizeof(arg.name); i++) {
+			if (l[i] == '\t') {
+				arg.name[i] = '\0';
+				break;
+			}
+			arg.name[i] = l[i];
+		}
 
-		if (strlen(s1) == 0 || strlen(s1) > 16) {
-			fprintf(stderr, "Invalid vmname %s from timer list file\n", s1);
+		/* can't found vmname in the string "l" or vmname is truncated */
+		if (i == 0 || i == sizeof(arg.name)) {
+			fprintf(stderr, "Invalid vmname %s from timer list file\n", arg.name);
 			continue;
 		}
 
-		memset(arg.name, 0, sizeof(arg.name));
-		strncpy(arg.name, s1, sizeof(arg.name));
-
-		expire = strtoul(s2, NULL, 10);
+		/* get expire from the string "l" */
+		expire = strtoul(&l[i + 1], NULL, 10);
 		if (expire == 0 || errno == ERANGE) {
 			perror("Invalid expire from timer list file");
 			continue;
@@ -202,7 +204,7 @@ static int load_timer_list(void)
 		if (ret != 0) {
 			fprintf(stderr, "Failed to add vm timer, errno %d", ret);
 		} else {
-			printf("vm %s will be activated at %ld seconds later\n", s1, expire);
+			printf("vm %s will be activated at %ld seconds later\n", arg.name, expire);
 		}
 	}