smb: fix invalid username check in smb3_fs_context_parse_param()

sunichi · smfrench · commit ed6612165b74 · 2025-11-11T10:01:47.000-06:00
Since the maximum return value of strnlen(..., CIFS_MAX_USERNAME_LEN)
is CIFS_MAX_USERNAME_LEN, length check in smb3_fs_context_parse_param()
is always FALSE and invalid.

Fix the comparison in if statement.

Signed-off-by: Yiqi Sun &lt;sunyiqixm@gmail.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
@@ -1470,7 +1470,7 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 			break;
 		}
 
-		if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) >
+		if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) ==
 		    CIFS_MAX_USERNAME_LEN) {
 			pr_warn("username too long\n");
 			goto cifs_parse_mount_err;

Original file line number	Diff line number	Diff line change
`@@ -1470,7 +1470,7 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,`
`1470`	`1470`	`break;`
`1471`	`1471`	`}`
`1472`	`1472`
`1473`		`- if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) >`
	`1473`	`+ if (strnlen(param->string, CIFS_MAX_USERNAME_LEN) ==`
`1474`	`1474`	`CIFS_MAX_USERNAME_LEN) {`
`1475`	`1475`	`pr_warn("username too long\n");`
`1476`	`1476`	`goto cifs_parse_mount_err;`