diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index 164b87138faf..de77d9aa22c6 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -146,6 +146,7 @@ static int chap_server_compute_md5(
 	unsigned char client_digest[MD5_SIGNATURE_SIZE];
 	unsigned char server_digest[MD5_SIGNATURE_SIZE];
 	unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
+	size_t compare_len;
 	struct iscsi_chap *chap = conn->auth_protocol;
 	struct crypto_hash *tfm;
 	struct hash_desc desc;
@@ -184,7 +185,9 @@ static int chap_server_compute_md5(
 		goto out;
 	}
 
-	if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 0) {
+	/* Include the terminating NULL in the compare */
+	compare_len = strlen(auth->userid) + 1;
+	if (strncmp(chap_n, auth->userid, compare_len) != 0) {
 		pr_err("CHAP_N values do not match!\n");
 		goto out;
 	}