tap: tap_open(): correctly initialize socket uid

mainline inclusion
from mainline-v6.3-rc1
commit 66b2c338
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6I7UC
CVE: CVE-2023-1076

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=66b2c338adce580dfce2199591e65e2bab889cff

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

sock_init_data() assumes that the `struct socket` passed in input is
contained in a `struct socket_alloc` allocated with sock_alloc().
However, tap_open() passes a `struct socket` embedded in a `struct
tap_queue` allocated with sk_alloc().
This causes a type confusion when issuing a container_of() with
SOCK_INODE() in sock_init_data() which results in assigning a wrong
sk_uid to the `struct sock` in input.
On default configuration, the type confused field overlaps with
padding bytes between `int vnet_hdr_sz` and `struct tap_dev __rcu
*tap` in `struct tap_queue`, which makes the uid of all tap sockets 0,
i.e., the root one.
Fix the assignment by using sock_init_data_uid().

Fixes: 86741ec2 ("net: core: Add a UID field to struct sock.")
Signed-off-by: NPietro Borrello <borrello@diag.uniroma1.it>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NBaisong Zhong <zhongbaisong@huawei.com>
Reviewed-by: NLiu Jian <liujian56@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

drivers/net/tap.c

@@ -523,7 +523,7 @@ static int tap_open(struct inode *inode, struct file *file)
 	q->sock.state = SS_CONNECTED;
 	q->sock.file = file;
 	q->sock.ops = &tap_socket_ops;
-	sock_init_data(&q->sock, &q->sk);
+	sock_init_data_uid(&q->sock, &q->sk, inode->i_uid);
 	q->sk.sk_write_space = tap_sock_write_space;
 	q->sk.sk_destruct = tap_sock_destruct;
 	q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;