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From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To: Hannes Reinecke <hare@suse.de>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Justin Stitt <justinstitt@google.com>,
        Kees Cook <keescook@chromium.org>, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc: dan.carpenter@linaro.org, kernel-janitors@vger.kernel.org,
        error27@gmail.com, harshit.m.mogalapalli@oracle.com
Subject: [PATCH] scsi: fcoe: Fix unsigned comparison with zero in store_ctlr_mode()
Date: Tue,  2 Jan 2024 00:52:45 -0800
Message-ID: <20240102085245.600570-1-harshit.m.mogalapalli@oracle.com>
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ctlr->mode is of unsigned type, it is never less than zero.

Fix this by using an extra varibale called 'res', to store return value
from sysfs_match_string() and assign that to ctlr->mode on the success
path.

Fixes: edc22a7c8688 ("scsi: fcoe: Use sysfs_match_string() over fcoe_parse_mode()")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis with smatch and only compile tested.
---
 drivers/scsi/fcoe/fcoe_sysfs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/fcoe/fcoe_sysfs.c b/drivers/scsi/fcoe/fcoe_sysfs.c
index 408a806bf4c2..c64a085a7ee2 100644
--- a/drivers/scsi/fcoe/fcoe_sysfs.c
+++ b/drivers/scsi/fcoe/fcoe_sysfs.c
@@ -263,6 +263,7 @@ static ssize_t store_ctlr_mode(struct device *dev,
 			       const char *buf, size_t count)
 {
 	struct fcoe_ctlr_device *ctlr = dev_to_ctlr(dev);
+	int res;
 
 	if (count > FCOE_MAX_MODENAME_LEN)
 		return -EINVAL;
@@ -279,12 +280,13 @@ static ssize_t store_ctlr_mode(struct device *dev,
 			return -ENOTSUPP;
 		}
 
-		ctlr->mode = sysfs_match_string(fip_conn_type_names, buf);
-		if (ctlr->mode < 0 || ctlr->mode == FIP_CONN_TYPE_UNKNOWN) {
+		res = sysfs_match_string(fip_conn_type_names, buf);
+		if (res < 0 || res == FIP_CONN_TYPE_UNKNOWN) {
 			LIBFCOE_SYSFS_DBG(ctlr, "Unknown mode %s provided.\n",
 					  buf);
 			return -EINVAL;
 		}
+		ctlr->mode = res;
 
 		ctlr->f->set_fcoe_ctlr_mode(ctlr);
 		LIBFCOE_SYSFS_DBG(ctlr, "Mode changed to %s.\n", buf);
-- 
2.39.3