Create typed structs for PIN-protected and admin metadata (#223)
MgmKey::set_protected and YubiKey::set_pin_last_changed both contained bugs resulting from the conversion of C pointer logic (incorrect buffer management). The new Metadata struct holds its own buffer, avoiding the problem. Also adds a protected management key integration test.
This commit is contained in:
str4d
+180
-122
@@ -30,153 +30,187 @@
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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use crate::{
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error::Error, serialization::*, transaction::Transaction, Buffer, TAG_ADMIN, TAG_PROTECTED,
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};
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use std::marker::PhantomData;
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use zeroize::Zeroizing;
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use crate::{error::Error, serialization::*, transaction::Transaction, Buffer};
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#[cfg(feature = "untested")]
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use crate::{CB_OBJ_MAX, CB_OBJ_TAG_MAX};
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#[cfg(feature = "untested")]
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use zeroize::Zeroizing;
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use std::iter;
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const TAG_ADMIN: u8 = 0x80;
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const TAG_PROTECTED: u8 = 0x88;
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pub const OBJ_ADMIN_DATA: u32 = 0x005f_ff00;
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pub const OBJ_PRINTED: u32 = 0x005f_c109;
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/// Get metadata item
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pub(crate) fn get_item(mut data: &[u8], tag: u8) -> Result<&[u8], Error> {
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while !data.is_empty() {
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let (remaining, tlv) = Tlv::parse(data)?;
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data = remaining;
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pub(crate) trait MetadataType: private::Sealed {}
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if tlv.tag == tag {
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// found tag
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return Ok(tlv.value);
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}
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}
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/// A type variable corresponding to PIN-protected metadata.
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pub(crate) enum Protected {}
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impl MetadataType for Protected {}
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Err(Error::GenericError)
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/// A type variable corresponding to administrative metadata.
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pub(crate) enum Admin {}
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impl MetadataType for Admin {}
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/// Metadata stored in a YubiKey.
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pub(crate) struct Metadata<T: MetadataType> {
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inner: Buffer,
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_marker: PhantomData<T>,
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}
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/// Set metadata item
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#[cfg(feature = "untested")]
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pub(crate) fn set_item(
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data: &mut [u8],
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pcb_data: &mut usize,
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cb_data_max: usize,
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tag: u8,
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p_item: &[u8],
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) -> Result<(), Error> {
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let mut cb_temp: usize = 0;
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let mut tag_temp: u8 = 0;
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let mut cb_len: usize = 0;
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let cb_item = p_item.len();
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/// PIN-protected metadata stored in a YubiKey.
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pub(crate) type ProtectedData = Metadata<Protected>;
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/// Administrative metadata stored in a YubiKey.
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pub(crate) type AdminData = Metadata<Admin>;
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let mut offset = 0;
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while offset < *pcb_data {
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tag_temp = data[offset];
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offset += 1;
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cb_len = get_length(&data[offset..], &mut cb_temp);
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offset += cb_len;
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if tag_temp == tag {
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break;
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impl<T: MetadataType> Default for Metadata<T> {
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fn default() -> Self {
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Metadata {
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inner: Zeroizing::new(vec![]),
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_marker: PhantomData::default(),
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}
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}
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}
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offset += cb_temp;
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impl<T: MetadataType> Metadata<T> {
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/// Read metadata
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pub(crate) fn read(txn: &Transaction<'_>) -> Result<Self, Error> {
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let data = txn.fetch_object(T::obj_id())?;
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Ok(Metadata {
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inner: Tlv::parse_single(data, T::tag())?,
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_marker: PhantomData::default(),
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})
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}
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if tag_temp != tag {
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if cb_item == 0 {
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// We've been asked to delete an existing item that isn't in the blob
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/// Write metadata
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#[cfg(feature = "untested")]
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pub(crate) fn write(&self, txn: &Transaction<'_>) -> Result<(), Error> {
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if self.inner.len() > CB_OBJ_MAX - CB_OBJ_TAG_MAX {
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return Err(Error::GenericError);
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}
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if self.inner.is_empty() {
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return Self::delete(txn);
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}
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let mut buf = Zeroizing::new(vec![0u8; CB_OBJ_MAX]);
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let len = Tlv::write(&mut buf, T::tag(), &self.inner)?;
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txn.save_object(T::obj_id(), &buf[..len])
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}
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/// Delete metadata
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#[cfg(feature = "untested")]
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pub(crate) fn delete(txn: &Transaction<'_>) -> Result<(), Error> {
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txn.save_object(T::obj_id(), &[])
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}
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/// Get metadata item
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pub(crate) fn get_item(&self, tag: u8) -> Result<&[u8], Error> {
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let mut data = &self.inner[..];
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while !data.is_empty() {
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let (remaining, tlv) = Tlv::parse(data)?;
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data = remaining;
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if tlv.tag == tag {
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// found tag
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return Ok(tlv.value);
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}
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}
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Err(Error::GenericError)
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}
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/// Set metadata item
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#[cfg(feature = "untested")]
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pub(crate) fn set_item(&mut self, tag: u8, item: &[u8]) -> Result<(), Error> {
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let mut cb_temp: usize = 0;
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let mut tag_temp: u8 = 0;
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let mut cb_len: usize = 0;
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let mut offset = 0;
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while offset < self.inner.len() {
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tag_temp = self.inner[offset];
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offset += 1;
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cb_len = get_length(&self.inner[offset..], &mut cb_temp);
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offset += cb_len;
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if tag_temp == tag {
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break;
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}
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offset += cb_temp;
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}
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if tag_temp != tag {
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if item.is_empty() {
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// We've been asked to delete an existing item that isn't in the blob
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return Ok(());
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}
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// We did not find an existing tag, append
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assert_eq!(offset, self.inner.len());
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self.inner
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.extend(iter::repeat(0).take(1 + get_length_size(item.len()) + item.len()));
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Tlv::write(&mut self.inner[offset..], tag, item)?;
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return Ok(());
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}
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// We did not find an existing tag, append
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*pcb_data += Tlv::write(&mut data[*pcb_data..], tag, p_item)?;
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// Found tag
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return Ok(());
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}
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// Found tag
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// Check length, if it matches, overwrite
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if cb_temp == cb_item {
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data[offset..offset + cb_item].copy_from_slice(p_item);
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return Ok(());
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}
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// Length doesn't match, expand/shrink to fit
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let next_offset = offset + cb_temp;
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// Must be signed to have negative offsets
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let cb_moved: isize = (cb_item as isize - cb_temp as isize)
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+ if cb_item != 0 {
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get_length_size(cb_item) as isize
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} else {
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// For tag, if deleting
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-1
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// Check length, if it matches, overwrite
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if cb_temp == item.len() {
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self.inner[offset..offset + item.len()].copy_from_slice(item);
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return Ok(());
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}
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// Accounts for different length encoding
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- cb_len as isize;
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// If length would cause buffer overflow, return error
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if (*pcb_data as isize + cb_moved) as usize > cb_data_max {
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return Err(Error::GenericError);
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// Length doesn't match, expand/shrink to fit
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let next_offset = offset + cb_temp;
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// Must be signed to have negative offsets
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let cb_moved: isize = (item.len() as isize - cb_temp as isize)
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+ if item.is_empty() {
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// For tag, if deleting
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-1
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} else {
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get_length_size(item.len()) as isize
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}
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// Accounts for different length encoding
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- cb_len as isize;
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// If length would cause buffer overflow, return error
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if (self.inner.len() as isize + cb_moved) as usize > CB_OBJ_MAX {
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return Err(Error::GenericError);
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}
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// Move remaining data
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let orig_len = self.inner.len();
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if cb_moved > 0 {
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self.inner.extend(iter::repeat(0).take(cb_moved as usize));
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}
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self.inner.copy_within(
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next_offset..orig_len,
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(next_offset as isize + cb_moved) as usize,
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);
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self.inner
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.resize((orig_len as isize + cb_moved) as usize, 0);
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// Re-encode item and insert
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if !item.is_empty() {
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offset -= cb_len;
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offset += set_length(&mut self.inner[offset..], item.len())?;
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self.inner[offset..offset + item.len()].copy_from_slice(item);
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}
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Ok(())
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}
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// Move remaining data
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data.copy_within(
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next_offset..*pcb_data,
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(next_offset as isize + cb_moved) as usize,
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);
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*pcb_data = (*pcb_data as isize + cb_moved) as usize;
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// Re-encode item and insert
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if cb_item != 0 {
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offset -= cb_len;
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offset += set_length(&mut data[offset..], cb_item)?;
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data[offset..offset + cb_item].copy_from_slice(p_item);
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}
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Ok(())
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}
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/// Read metadata
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pub(crate) fn read(txn: &Transaction<'_>, tag: u8) -> Result<Buffer, Error> {
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let obj_id = match tag {
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TAG_ADMIN => OBJ_ADMIN_DATA,
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TAG_PROTECTED => OBJ_PRINTED,
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_ => return Err(Error::InvalidObject),
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};
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let data = txn.fetch_object(obj_id)?;
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Tlv::parse_single(data, tag)
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}
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/// Write metadata
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#[cfg(feature = "untested")]
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pub(crate) fn write(txn: &Transaction<'_>, tag: u8, data: &[u8]) -> Result<(), Error> {
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if data.len() > CB_OBJ_MAX - CB_OBJ_TAG_MAX {
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return Err(Error::GenericError);
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}
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let obj_id = match tag {
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TAG_ADMIN => OBJ_ADMIN_DATA,
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TAG_PROTECTED => OBJ_PRINTED,
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_ => return Err(Error::InvalidObject),
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};
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if data.is_empty() {
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// Deleting metadata
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return txn.save_object(obj_id, &[]);
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}
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let mut buf = Zeroizing::new(vec![0u8; CB_OBJ_MAX]);
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let len = Tlv::write(&mut buf, tag, data)?;
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txn.save_object(obj_id, &buf[..len])
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}
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/// Get the size of a length tag for the given length
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@@ -190,3 +224,27 @@ fn get_length_size(length: usize) -> usize {
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3
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}
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}
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mod private {
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use super::*;
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pub trait Sealed {
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fn tag() -> u8;
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fn obj_id() -> u32;
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}
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impl Sealed for Protected {
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fn tag() -> u8 {
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TAG_PROTECTED
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}
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fn obj_id() -> u32 {
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OBJ_PRINTED
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}
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}
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impl Sealed for Admin {
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fn tag() -> u8 {
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TAG_ADMIN
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}
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fn obj_id() -> u32 {
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OBJ_ADMIN_DATA
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}
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}
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}
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