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SubjectRe: [PATCH net-next v3 3/3] tap: tap_open(): correctly initialize socket uid
On Sat, Feb 4, 2023 at 6:39 PM Pietro Borrello
<borrello@diag.uniroma1.it> wrote:
>
> 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: 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>

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