Change IoVecBuffer[Mut] len to u32

Signed-off-by: Brandon Pike <[email protected]>

src/vmm/src/devices/virtio/iovec.rs

@@ -18,6 +18,8 @@ pub enum IoVecError {
  WriteOnlyDescriptor,
  /// Tried to create an 'IoVecMut` from a read-only descriptor chain
  ReadOnlyDescriptor,
+ /// Tried to create an `IoVec` or `IoVecMut` from a descriptor chain that was too large
+ OverflowedDescriptor,
  /// Guest memory error: {0}
  GuestMemory(#[from] GuestMemoryError),
 }
@@ -40,14 +42,14 @@ pub struct IoVecBuffer {
  // container of the memory regions included in this IO vector
  vecs: IoVecVec,
  // Total length of the IoVecBuffer
- len: usize,
+ len: u32,
 }
 
 impl IoVecBuffer {
  /// Create an `IoVecBuffer` from a `DescriptorChain`
  pub fn from_descriptor_chain(head: DescriptorChain) -> Result<Self, IoVecError> {
  let mut vecs = IoVecVec::new();
- let mut len = 0usize;
+ let mut len = 0u32;
 
  let mut next_descriptor = Some(head);
  while let Some(desc) = next_descriptor {
@@ -68,7 +70,9 @@ impl IoVecBuffer {
  iov_base,
  iov_len: desc.len as size_t,
  });
- len += desc.len as usize;
+ len = len
+ .checked_add(desc.len)
+ .ok_or(IoVecError::OverflowedDescriptor)?;
 
  next_descriptor = desc.next_descriptor();
  }
@@ -77,7 +81,7 @@ impl IoVecBuffer {
  }
 
  /// Get the total length of the memory regions covered by this `IoVecBuffer`
- pub(crate) fn len(&self) -> usize {
+ pub(crate) fn len(&self) -> u32 {
  self.len
  }
 
@@ -106,7 +110,7 @@ impl IoVecBuffer {
  mut buf: &mut [u8],
  offset: usize,
  ) -> Result<(), VolatileMemoryError> {
- if offset < self.len() {
+ if offset < self.len() as usize {
  let expected = buf.len();
  let bytes_read = self.read_volatile_at(&mut buf, offset, expected)?;
 
@@ -188,14 +192,14 @@ pub struct IoVecBufferMut {
  // container of the memory regions included in this IO vector
  vecs: IoVecVec,
  // Total length of the IoVecBufferMut
- len: usize,
+ len: u32,
 }
 
 impl IoVecBufferMut {
  /// Create an `IoVecBufferMut` from a `DescriptorChain`
  pub fn from_descriptor_chain(head: DescriptorChain) -> Result<Self, IoVecError> {
  let mut vecs = IoVecVec::new();
- let mut len = 0usize;
+ let mut len = 0u32;
 
  for desc in head {
  if !desc.is_write_only() {
@@ -217,14 +221,16 @@ impl IoVecBufferMut {
  iov_base,
  iov_len: desc.len as size_t,
  });
- len += desc.len as usize;
+ len = len
+ .checked_add(desc.len)
+ .ok_or(IoVecError::OverflowedDescriptor)?;
  }
 
  Ok(Self { vecs, len })
  }
 
  /// Get the total length of the memory regions covered by this `IoVecBuffer`
- pub(crate) fn len(&self) -> usize {
+ pub(crate) fn len(&self) -> u32 {
  self.len
  }
 
@@ -244,7 +250,7 @@ impl IoVecBufferMut {
  mut buf: &[u8],
  offset: usize,
  ) -> Result<(), VolatileMemoryError> {
- if offset < self.len() {
+ if offset < self.len() as usize {
  let expected = buf.len();
  let bytes_written = self.write_volatile_at(&mut buf, offset, expected)?;
 

src/vmm/src/devices/virtio/net/device.rs

@@ -462,7 +462,7 @@ impl Net {
 
  if let Some(ns) = mmds_ns {
  if ns.is_mmds_frame(headers) {
- let mut frame = vec![0u8; frame_iovec.len() - vnet_hdr_len()];
+ let mut frame = vec![0u8; frame_iovec.len() as usize - vnet_hdr_len()];
  // Ok to unwrap here, because we are passing a buffer that has the exact size
  // of the `IoVecBuffer` minus the VNET headers.
  frame_iovec
@@ -609,7 +609,7 @@ impl Net {
  };
 
  // We only handle frames that are up to MAX_BUFFER_SIZE
- if buffer.len() > MAX_BUFFER_SIZE {
+ if buffer.len() as usize > MAX_BUFFER_SIZE {
  error!("net: received too big frame from driver");
  self.metrics.tx_malformed_frames.inc();
  tx_queue

src/vmm/src/devices/virtio/rng/device.rs

@@ -112,7 +112,7 @@ impl Entropy {
  return Ok(0);
  }
 
- let mut rand_bytes = vec![0; iovec.len()];
+ let mut rand_bytes = vec![0; iovec.len() as usize];
  rand::fill(&mut rand_bytes).map_err(|err| {
  METRICS.host_rng_fails.inc();
  err

src/vmm/src/devices/virtio/vsock/csm/connection.rs

@@ -216,7 +216,7 @@ where
 
  // The maximum amount of data we can read in is limited by both the RX buffer size and
  // the peer available buffer space.
- let max_len = std::cmp::min(pkt.buf_size(), self.peer_avail_credit());
+ let max_len = std::cmp::min(pkt.buf_size() as usize, self.peer_avail_credit());
 
  // Read data from the stream straight to the RX buffer, for maximum throughput.
  match pkt.read_at_offset_from(&mut self.stream, 0, max_len) {

src/vmm/src/devices/virtio/vsock/mod.rs

@@ -110,7 +110,7 @@ mod defs {
 #[rustfmt::skip]
 pub enum VsockError {
  /** The total length of the descriptor chain ({0}) is too short to hold a packet of length {1} + header */
- DescChainTooShortForPacket(usize, u32),
+ DescChainTooShortForPacket(u32, u32),
  /// Empty queue
  EmptyQueue,
  /// EventFd error: {0}
@@ -122,6 +122,8 @@ pub enum VsockError {
  /** The total length of the descriptor chain ({0}) is less than the number of bytes required\
  to hold a vsock packet header.*/
  DescChainTooShortForHeader(usize),
+ /// The descriptor chain length was greater than the max ([u32::MAX])
+ DescChainOverflow,
  /// The vsock header `len` field holds an invalid value: {0}
  InvalidPktLen(u32),
  /// A data fetch was attempted when no data was available.
@@ -144,6 +146,7 @@ impl From<IoVecError> for VsockError {
  IoVecError::WriteOnlyDescriptor => VsockError::UnreadableDescriptor,
  IoVecError::ReadOnlyDescriptor => VsockError::UnwritableDescriptor,
  IoVecError::GuestMemory(err) => VsockError::GuestMemoryMmap(err),
+ IoVecError::OverflowedDescriptor => VsockError::DescChainOverflow,
  }
  }
 }

src/vmm/src/devices/virtio/vsock/packet.rs

@@ -139,7 +139,7 @@ impl VsockPacket {
  return Err(VsockError::InvalidPktLen(hdr.len));
  }
 
- if (hdr.len as usize) > buffer.len() - VSOCK_PKT_HDR_SIZE as usize {
+ if (hdr.len) > buffer.len() - VSOCK_PKT_HDR_SIZE {
  return Err(VsockError::DescChainTooShortForPacket(
  buffer.len(),
  hdr.len,
@@ -160,8 +160,8 @@ impl VsockPacket {
  pub fn from_rx_virtq_head(chain: DescriptorChain) -> Result<Self, VsockError> {
  let buffer = IoVecBufferMut::from_descriptor_chain(chain)?;
 
- if buffer.len() < VSOCK_PKT_HDR_SIZE as usize {
- return Err(VsockError::DescChainTooShortForHeader(buffer.len()));
+ if buffer.len() < VSOCK_PKT_HDR_SIZE {
+ return Err(VsockError::DescChainTooShortForHeader(buffer.len() as usize));
  }
 
  Ok(Self {
@@ -212,7 +212,7 @@ impl VsockPacket {
  VsockPacketBuffer::Tx(ref iovec_buf) => iovec_buf.len(),
  VsockPacketBuffer::Rx(ref iovec_buf) => iovec_buf.len(),
  };
- chain_length - VSOCK_PKT_HDR_SIZE as usize
+ (chain_length - VSOCK_PKT_HDR_SIZE) as usize
  }
 
  pub fn read_at_offset_from<T: ReadVolatile + Debug>(
@@ -225,8 +225,7 @@ impl VsockPacket {
  VsockPacketBuffer::Tx(_) => Err(VsockError::UnwritableDescriptor),
  VsockPacketBuffer::Rx(ref mut buffer) => {
  if count
- > buffer
- .len()
+ > (buffer.len() as usize)
  .saturating_sub(VSOCK_PKT_HDR_SIZE as usize)
  .saturating_sub(offset)
  {
@@ -249,8 +248,7 @@ impl VsockPacket {
  match self.buffer {
  VsockPacketBuffer::Tx(ref buffer) => {
  if count
- > buffer
- .len()
+ > (buffer.len() as usize)
  .saturating_sub(VSOCK_PKT_HDR_SIZE as usize)
  .saturating_sub(offset)
  {
@@ -427,10 +425,7 @@ mod tests {
  .unwrap(),
  )
  .unwrap();
- assert_eq!(
- pkt.buf_size(),
- handler_ctx.guest_txvq.dtable[1].len.get() as usize
- );
+ assert_eq!(pkt.buf_size(), handler_ctx.guest_txvq.dtable[1].len.get());
  }
 
  // Test case: error on write-only hdr descriptor.