From: Pietro Borrello borrello@diag.uniroma1.it
[ Upstream commit a096ccca6e503a5c575717ff8a36ace27510ab0a ]
sock_init_data() assumes that the `struct socket` passed in input is contained in a `struct socket_alloc` allocated with sock_alloc(). However, tun_chr_open() passes a `struct socket` embedded in a `struct tun_file` 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 the high 4 bytes of `struct tun_struct __rcu *tun` of `struct tun_file`, NULL at the time of call, which makes the uid of all tun sockets 0, i.e., the root one. Fix the assignment by using sock_init_data_uid().
Fixes: 86741ec25462 ("net: core: Add a UID field to struct sock.") Signed-off-by: Pietro Borrello borrello@diag.uniroma1.it Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a7d17c680f4a0..745131b2d6dbf 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -3448,7 +3448,7 @@ static int tun_chr_open(struct inode *inode, struct file * file) tfile->socket.file = file; tfile->socket.ops = &tun_socket_ops;
- sock_init_data(&tfile->socket, &tfile->sk); + sock_init_data_uid(&tfile->socket, &tfile->sk, inode->i_uid);
tfile->sk.sk_write_space = tun_sock_write_space; tfile->sk.sk_sndbuf = INT_MAX;