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

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`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: 5eaa5fbb6e ("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>

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Sagar Taunk 2026-09-25 08:55:04 +00:00 • committed by Paolo Abeni

parent f8932b2c0c

commit 0923198be4

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rust/kernel/net/netlink.rs

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