Add advisory for unsound problems in kvm-ioctls

crates/kvm-ioctls/RUSTSEC-0000-0000.md

@@ -0,0 +1,25 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "kvm-ioctls"
+url = "https://github.com/rust-vmm/kvm/pull/298"
+date = "2024-12-05"
+keywords = ["unsound", "1.82"]
+informational = "unsound"
+
+[versions]
+patched = [">= 0.19.1"]
+
+[affected]
+os = ["linux"]
+functions = { "kvm_ioctls::ioctls::vm::VmFd::create_device" = ["<= 0.19.0"] }
+```
+
+# Undefined behaviour in `kvm_ioctls::ioctls::vm::VmFd::create_device`
+
+An issue was identified in the `VmFd::create_device function`, leading to undefined behavior and miscompilations on rustc 1.82.0 and newer due to the function's violation of Rust's pointer safety rules.
+
+The function downcasted a mutable reference to its `struct kvm_create_device` argument to an immutable pointer, and then proceeded to pass this pointer to a mutating system call. Rustc 1.82.0 and newer elides subsequent reads of this structure's fields, meaning code will not see the value written by the kernel into the `fd` member. Instead, the code will observe the value that this field was initialized to prior to calling `VmFd::create_device` (usually, 0).
+
+The issue started in kvm-ioctls 0.1.0 and was fixed in 0.19.1 by correctly using
+a mutable pointer.