sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names

The standard return value for unsupported attribute names is
-EOPNOTSUPP, as opposed to undefined but supported attributes
(-ENODATA).

Also, fail for attribute names like "system.sockprotonameXXX" and
simplify the code a bit.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 6 insertions, 18 deletions

diff --git a/net/socket.c b/net/socket.c
index a1bd16106625..9b3dca699a3d 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -469,27 +469,15 @@ static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
 static ssize_t sockfs_getxattr(struct dentry *dentry, struct inode *inode,
                                const char *name, void *value, size_t size)
 {
-        const char *proto_name;
-        size_t proto_size;
-        int error;
-
-        error = -ENODATA;
-        if (!strncmp(name, XATTR_NAME_SOCKPROTONAME, XATTR_NAME_SOCKPROTONAME_LEN)) {
-                proto_name = dentry->d_name.name;
-                proto_size = strlen(proto_name);
-
+        if (!strcmp(name, XATTR_NAME_SOCKPROTONAME)) {
                 if (value) {
-                        error = -ERANGE;
-                        if (proto_size + 1 > size)
-                                goto out;
-
-                        strncpy(value, proto_name, proto_size + 1);
+                        if (dentry->d_name.len + 1 > size)
+                                return -ERANGE;
+                        memcpy(value, dentry->d_name.name, dentry->d_name.len + 1);
                 }
-                error = proto_size + 1;
+                return dentry->d_name.len + 1;
         }
-
-out:
-        return error;
+        return -EOPNOTSUPP;
 }
 
 static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,