linux-kernel - [PATCH 2/2] dm verity: allow only one verify mode

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Message-Id: <1615464651-23675-2-git-send-email-jhs2.lee@samsung.com>
Date:   Thu, 11 Mar 2021 21:10:51 +0900
From:   JeongHyeon Lee <jhs2.lee@...sung.com>
To:     snitzer@...hat.com
Cc:     agk@...hat.com, dm-devel@...hat.com, linux-kernel@...r.kernel.org,
        JeongHyeon Lee <jhs2.lee@...sung.com>
Subject: [PATCH 2/2] dm verity: allow only one verify mode

If there are multiple verity mode when parsing the verity mode of dm
verity table, it will be set as the last one.
So set to 'allow only once' to prevent it.

Signed-off-by: JeongHyeon Lee <jhs2.lee@...sung.com>
---
 drivers/md/dm-verity-target.c | 38 ++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 808a98ef624c..b76431dc7721 100644
--- a/drivers/md/dm-verity-target.c
+++ b/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 = "Already verity mode set";
+				return r;
+			}
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
-- 
2.17.1