dm-verity: fix a memory leak if some arguments are specified multiple times

JIRA: https://issues.redhat.com/browse/RHEL-119008
Upstream Status: kernel/git/torvalds/linux.git

commit 66be40a
Author: Mikulas Patocka <mpatocka@redhat.com>
Date:   Tue Jun 3 18:55:50 2025 +0200

    dm-verity: fix a memory leak if some arguments are specified multiple times

    If some of the arguments "check_at_most_once", "ignore_zero_blocks",
    "use_fec_from_device", "root_hash_sig_key_desc" were specified more than
    once on the target line, a memory leak would happen.

    This commit fixes the memory leak. It also fixes error handling in
    verity_verify_sig_parse_opt_args.

    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
    Cc: stable@vger.kernel.org

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

Author: bmarzins

drivers/md/dm-verity-fec.c

@@ -593,6 +593,10 @@ int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
 	(*argc)--;
 
 	if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {
+		if (v->fec->dev) {
+			ti->error = "FEC device already specified";
+			return -EINVAL;
+		}
 		r = dm_get_device(ti, arg_value, BLK_OPEN_READ, &v->fec->dev);
 		if (r) {
 			ti->error = "FEC device lookup failed";

drivers/md/dm-verity-target.c

@@ -1123,6 +1123,9 @@ static int verity_alloc_most_once(struct dm_verity *v)
 {
 	struct dm_target *ti = v->ti;
 
+	if (v->validated_blocks)
+		return 0;
+
 	/* the bitset can only handle INT_MAX blocks */
 	if (v->data_blocks > INT_MAX) {
 		ti->error = "device too large to use check_at_most_once";
@@ -1146,6 +1149,9 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
 	struct dm_verity_io *io;
 	u8 *zero_data;
 
+	if (v->zero_digest)
+		return 0;
+
 	v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
 
 	if (!v->zero_digest)
@@ -1580,7 +1586,7 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 			goto bad;
 	}
 
-	/* Root hash signature is  a optional parameter*/
+	/* Root hash signature is an optional parameter */
 	r = verity_verify_root_hash(root_hash_digest_to_validate,
 				    strlen(root_hash_digest_to_validate),
 				    verify_args.sig,

drivers/md/dm-verity-verify-sig.c

@@ -71,9 +71,14 @@ int verity_verify_sig_parse_opt_args(struct dm_arg_set *as,
 				     const char *arg_name)
 {
 	struct dm_target *ti = v->ti;
-	int ret = 0;
+	int ret;
 	const char *sig_key = NULL;
 
+	if (v->signature_key_desc) {
+		ti->error = DM_VERITY_VERIFY_ERR("root_hash_sig_key_desc already specified");
+		return -EINVAL;
+	}
+
 	if (!*argc) {
 		ti->error = DM_VERITY_VERIFY_ERR("Signature key not specified");
 		return -EINVAL;
@@ -83,14 +88,18 @@ int verity_verify_sig_parse_opt_args(struct dm_arg_set *as,
 	(*argc)--;
 
 	ret = verity_verify_get_sig_from_key(sig_key, sig_opts);
-	if (ret < 0)
+	if (ret < 0) {
 		ti->error = DM_VERITY_VERIFY_ERR("Invalid key specified");
+		return ret;
+	}
 
 	v->signature_key_desc = kstrdup(sig_key, GFP_KERNEL);
-	if (!v->signature_key_desc)
+	if (!v->signature_key_desc) {
+		ti->error = DM_VERITY_VERIFY_ERR("Could not allocate memory for signature key");
 		return -ENOMEM;
+	}
 
-	return ret;
+	return 0;
 }
 
 /*