[PATCH nvme-7.3 v3 4/4] nvme-fabrics: add helper for DH-CHAP secret options

[raoxu]

From: Xu Rao <raoxu@xxxxxxxxxxxxx>

The dhchap_secret and dhchap_ctrl_secret options share the same string
replacement and DHHC-1 validation rules.  The replacement step can reuse
nvmf_parse_string_option(), leaving only the DH-CHAP-specific validation
in a dedicated helper.

Add nvmf_parse_dhchap_secret() to reuse nvmf_parse_string_option() for the
common allocation and ownership handling, then perform the DH-CHAP-specific
validation.  If validation fails, discard the installed value with
kfree_sensitive() and clear the field so the normal options cleanup can
safely run after nvmf_parse_options() returns an error.

Both secret options share this helper because their parsing and validation
rules are identical.

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Xu Rao <raoxu@xxxxxxxxxxxxx>
---
 drivers/nvme/host/fabrics.c | 47 ++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 24385e777307..207b05ade022 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -725,6 +725,24 @@ static int nvmf_parse_string_option(substring_t *args, char **dst)
 	return 0;
 }
 
+static int nvmf_parse_dhchap_secret(substring_t *args, char **secret)
+{
+	int ret;
+
+	ret = nvmf_parse_string_option(args, secret);
+	if (ret)
+		return ret;
+
+	if (strlen(*secret) < 11 || strncmp(*secret, "DHHC-1:", 7)) {
+		pr_err("Invalid DH-CHAP secret %s\n", *secret);
+		kfree_sensitive(*secret);
+		*secret = NULL;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 		const char *buf)
 {
@@ -1010,34 +1028,15 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			opts->discovery_nqn = true;
 			break;
 		case NVMF_OPT_DHCHAP_SECRET:
-			p = match_strdup(args);
-			if (!p) {
-				ret = -ENOMEM;
-				goto out;
-			}
-			if (strlen(p) < 11 || strncmp(p, "DHHC-1:", 7)) {
-				pr_err("Invalid DH-CHAP secret %s\n", p);
-				kfree_sensitive(p);
-				ret = -EINVAL;
+			ret = nvmf_parse_dhchap_secret(args, &opts->dhchap_secret);
+			if (ret)
 				goto out;
-			}
-			kfree(opts->dhchap_secret);
-			opts->dhchap_secret = p;
 			break;
 		case NVMF_OPT_DHCHAP_CTRL_SECRET:
-			p = match_strdup(args);
-			if (!p) {
-				ret = -ENOMEM;
-				goto out;
-			}
-			if (strlen(p) < 11 || strncmp(p, "DHHC-1:", 7)) {
-				pr_err("Invalid DH-CHAP secret %s\n", p);
-				kfree_sensitive(p);
-				ret = -EINVAL;
+			ret = nvmf_parse_dhchap_secret(args,
+						       &opts->dhchap_ctrl_secret);
+			if (ret)
 				goto out;
-			}
-			kfree(opts->dhchap_ctrl_secret);
-			opts->dhchap_ctrl_secret = p;
 			break;
 		case NVMF_OPT_TLS:
 			if (!IS_ENABLED(CONFIG_NVME_TCP_TLS)) {
-- 
2.50.1