From acda9b1380c59ff3f736546d68ce5ee862169eb6 Mon Sep 17 00:00:00 2001 From: Anatol Belski Date: Fri, 15 May 2026 01:27:25 +0200 Subject: [PATCH] vm-virtio: checked_descriptor: Add unit test for one past memory end Submit a descriptor whose buffer extends exactly one byte past the end of guest RAM and verify CheckedDescriptorIter rejects it, with failed_addr returning the descriptor's start address. Signed-off-by: Anatol Belski --- vm-virtio/src/checked_descriptor.rs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/vm-virtio/src/checked_descriptor.rs b/vm-virtio/src/checked_descriptor.rs index 392b83482..4d4f37e28 100644 --- a/vm-virtio/src/checked_descriptor.rs +++ b/vm-virtio/src/checked_descriptor.rs @@ -362,4 +362,19 @@ mod unit_tests { assert_eq!(desc.addr().0, addr); assert_eq!(desc.len(), LEN); } + + #[test] + fn rejects_descriptor_one_past_memory_end() { + // A descriptor whose buffer extends one byte past the end of guest + // RAM must be rejected. + const MEM_SIZE: usize = 128 * 1024; + const LEN: u32 = 256; + let addr = (MEM_SIZE as u64) - LEN as u64 + 1; + let (_mem, mem_atomic, mut queue) = setup_vq(MEM_SIZE, addr, LEN, 0); + let mem_guard = mem_atomic.memory(); + let mut chain = queue.pop_descriptor_chain(mem_guard).unwrap(); + let mut it = chain.checked_iter(None); + let result = it.next().expect("must yield an item"); + assert_eq!(result.unwrap_err(), GuestAddress(addr)); + } }