rust: net: netlink: validate attribute length before casting to `c_int`

`put()` trusted an unchecked `as` cast from `usize` to `c_int`.
When the length exceeds `i32::MAX` that cast wraps around to a
negative value.

This ultimately resulted in a kernel panic when the reinterpreted
value via `__nla_reserve()` and `skb_put()` became enormous.

Validate payload and header both fit together in a `u16`, rejecting
any payload that wouldn't leave room for `NLA_HDRLEN`.

Fixes: 5eaa5fbb6e6c ("rust: netlink: add raw netlink abstraction")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Sagar Taunk <sagartaunk@proton.me>
Link: https://patch.msgid.link/20260925085449.22553-1-sagartaunk@proton.me
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions