Fuzzing snapshot2 (#2)

* Fuzzing tests for snapshot2

* Randomize program and data

fuzz/Cargo.toml

@@ -12,10 +12,14 @@ cargo-fuzz = true
 libfuzzer-sys = "0.4"
 spike-sys = "0.1.2"
 
+
 [dependencies.ckb-vm]
 path = ".."
 features = ["asm"]
 
+[dependencies.ckb-vm-definitions]
+path = "../definitions"
+
 # Prevent this from interfering with workspaces
 [workspace]
 members = ["."]
@@ -43,3 +47,10 @@ name = "isa_b"
 path = "fuzz_targets/isa_b.rs"
 test = false
 doc = false
+
+
+[[bin]]
+name = "snapshot2"
+path = "fuzz_targets/snapshot2.rs"
+test = false
+doc = false

fuzz/fuzz_targets/snapshot2.rs

@@ -0,0 +1,146 @@
+#![no_main]
+use ckb_vm::{
+    elf::{LoadingAction, ProgramMetadata},
+    machine::VERSION2,
+    memory::{round_page_down, round_page_up, FLAG_EXECUTABLE, FLAG_FREEZED},
+    snapshot2::{DataSource, Snapshot2Context},
+    Bytes, CoreMachine, DefaultMachine, DefaultMachineBuilder, Error, Memory, ISA_A, ISA_B,
+    ISA_IMC, ISA_MOP,
+};
+use ckb_vm_definitions::{asm::AsmCoreMachine, RISCV_MAX_MEMORY};
+use libfuzzer_sys::fuzz_target;
+use std::collections::VecDeque;
+
+struct Deque {
+    n: VecDeque<u8>,
+}
+
+impl Deque {
+    fn new(data: [u8; 32]) -> Self {
+        Self {
+            n: VecDeque::from(data),
+        }
+    }
+
+    fn u8(&mut self) -> u8 {
+        let r = self.n.pop_front().unwrap();
+        self.n.push_back(r);
+        r
+    }
+
+    fn u16(&mut self) -> u16 {
+        let mut r = [0u8; 2];
+        r.fill_with(|| self.u8());
+        u16::from_le_bytes(r)
+    }
+
+    fn u32(&mut self) -> u32 {
+        let mut r = [0u8; 4];
+        r.fill_with(|| self.u8());
+        u32::from_le_bytes(r)
+    }
+}
+
+const DATA_SOURCE_PROGRAM: u32 = 0;
+const DATA_SOURCE_CONTENT: u32 = 1;
+
+#[derive(Clone)]
+pub struct DummyData {
+    pub program: Bytes,
+    pub content: Bytes,
+}
+
+impl DataSource<u32> for DummyData {
+    fn load_data(&self, id: &u32, offset: u64, length: u64) -> Result<(Bytes, u64), Error> {
+        let data = match *id {
+            DATA_SOURCE_PROGRAM => &self.program,
+            DATA_SOURCE_CONTENT => &self.content,
+            _ => unreachable!(),
+        };
+        Ok((
+            data.slice(offset as usize..offset as usize + length as usize),
+            length as u64,
+        ))
+    }
+}
+
+fn build_machine() -> DefaultMachine<Box<AsmCoreMachine>> {
+    let isa = ISA_IMC | ISA_A | ISA_B | ISA_MOP;
+    let core_machine = AsmCoreMachine::new(isa, VERSION2, u64::max_value());
+    DefaultMachineBuilder::new(core_machine).build()
+}
+
+fuzz_target!(|data: [u8; 32]| {
+    let mut deque = Deque::new(data);
+    let dummy_data = {
+        let mut program = vec![0u8; deque.u16() as usize + 1024];
+        for i in 0..program.len() {
+            program[i] = (i % 256) as u8;
+        }
+        let mut content = vec![0u8; deque.u16() as usize + 1024];
+        for i in 0..content.len() {
+            content[i] = (i / 256) as u8;
+        }
+        DummyData {
+            program: program.into(),
+            content: content.into(),
+        }
+    };
+    let mut loading_action_vec: Vec<LoadingAction> = Vec::new();
+    for i in 0..2 + deque.u8() as usize % 3 {
+        let segsize = deque.u16() as u64 % 1024;
+        let p_vaddr = i as u64 * 1024 * 256;
+        let p_memsz = segsize;
+        let p_offset = deque.u32() as u64 % (dummy_data.program.len() as u64 - segsize);
+        let p_filesz = segsize;
+        let aligned_start = round_page_down(p_vaddr);
+        let padding_start = (p_vaddr).wrapping_sub(aligned_start);
+        let size = round_page_up((p_memsz).wrapping_add(padding_start));
+        let slice_start = p_offset;
+        let slice_end = p_offset.wrapping_add(p_filesz);
+        assert!(slice_start <= slice_end);
+        loading_action_vec.push(LoadingAction {
+            addr: aligned_start,
+            size,
+            flags: FLAG_EXECUTABLE | FLAG_FREEZED,
+            source: slice_start as u64..slice_end as u64,
+            offset_from_addr: padding_start,
+        })
+    }
+    let mut ctx = Snapshot2Context::new(dummy_data.clone());
+    let metadata = ProgramMetadata {
+        actions: loading_action_vec,
+        entry: 0,
+    };
+
+    let mut machine1 = build_machine();
+    let mut machine2 = build_machine();
+    machine1
+        .load_program_with_metadata(&dummy_data.program, &metadata, &vec![])
+        .unwrap();
+    ctx.mark_program(&mut machine1, &metadata, &0, 0).unwrap();
+    for i in 0..2 + deque.u8() as usize % 3 {
+        let id = i as u32 % 2;
+        let data = match id {
+            DATA_SOURCE_PROGRAM => &dummy_data.program,
+            DATA_SOURCE_CONTENT => &dummy_data.content,
+            _ => unreachable!(),
+        };
+        let length = deque.u16() as u64 % 1024;
+        let offset = deque.u32() as u64 % (data.len() as u64 - length);
+        let addr = 1024 * 1024 + (deque.u8() as u64 % 4) * 1024 * 256;
+        ctx.store_bytes(&mut machine1, addr, &id, offset, length)
+            .unwrap();
+    }
+    let snapshot = ctx.make_snapshot(&mut machine1).unwrap();
+    ctx.resume(&mut machine2, &snapshot).unwrap();
+    let mem1 = machine1
+        .memory_mut()
+        .load_bytes(0, RISCV_MAX_MEMORY as u64)
+        .unwrap();
+    let mem2 = machine2
+        .memory_mut()
+        .load_bytes(0, RISCV_MAX_MEMORY as u64)
+        .unwrap();
+    assert_eq!(mem1, mem2);
+});