dm verity: allow only one error handling mode

mainline inclusion
from mainline-v5.13-rc1
commit 219a9b5e
category: bugfix
bugzilla: 51874
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=219a9b5e738b75a6a5e9effe1d72f60037a2f131

-----------------------------------------------

If more than one one handling mode is requested during DM verity table
load, the last requested mode will be used.

Change this to impose more strict checking so that the table load will
fail if more than one error handling mode is requested.
Signed-off-by: NJeongHyeon Lee <jhs2.lee@samsung.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NLuo Meng <luomeng12@huawei.com>
Reviewed-by: NZhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/md/dm-verity-target.c

@@ -893,6 +893,28 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
 	return r;
 }
 
+static inline bool verity_is_verity_mode(const char *arg_name)
+{
+	return (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING) ||
+		!strcasecmp(arg_name, DM_VERITY_OPT_RESTART) ||
+		!strcasecmp(arg_name, DM_VERITY_OPT_PANIC));
+}
+
+static int verity_parse_verity_mode(struct dm_verity *v, const char *arg_name)
+{
+	if (v->mode)
+		return -EINVAL;
+
+	if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING))
+		v->mode = DM_VERITY_MODE_LOGGING;
+	else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART))
+		v->mode = DM_VERITY_MODE_RESTART;
+	else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC))
+		v->mode = DM_VERITY_MODE_PANIC;
+
+	return 0;
+}
+
 static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
 				 struct dm_verity_sig_opts *verify_args)
 {
@@ -916,16 +938,12 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
 		arg_name = dm_shift_arg(as);
 		argc--;
 
-		if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
-			v->mode = DM_VERITY_MODE_LOGGING;
-			continue;
-
-		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
-			v->mode = DM_VERITY_MODE_RESTART;
-			continue;
-
-		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC)) {
-			v->mode = DM_VERITY_MODE_PANIC;
+		if (verity_is_verity_mode(arg_name)) {
+			r = verity_parse_verity_mode(v, arg_name);
+			if (r) {
+				ti->error = "Conflicting error handling parameters";
+				return r;
+			}
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
@@ -1242,7 +1260,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 
 static struct target_type verity_target = {
 	.name		= "verity",
-	.version	= {1, 7, 0},
+	.version	= {1, 8, 0},
 	.module		= THIS_MODULE,
 	.ctr		= verity_ctr,
 	.dtr		= verity_dtr,