[PATCH 4.4 059/230] sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names

From: Greg Kroah-Hartman
Date: Fri Mar 22 2019 - 07:30:19 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Andreas Gruenbacher <agruenba@xxxxxxxxxx>

commit 971df15bd54ad46e907046ff33750a137b2f0096 upstream.

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@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
[removes a build warning on 4.4.y - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/socket.c | 24 ++++++------------------
1 file changed, 6 insertions(+), 18 deletions(-)

--- a/net/socket.c
+++ b/net/socket.c
@@ -470,27 +470,15 @@ static struct socket *sockfd_lookup_ligh
static ssize_t sockfs_getxattr(struct dentry *dentry,
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,