diff options
Diffstat (limited to 'src/index_entry.rs')
| -rw-r--r-- | src/index_entry.rs | 98 |
1 files changed, 71 insertions, 27 deletions
diff --git a/src/index_entry.rs b/src/index_entry.rs index b6fcb55..c9f0805 100644 --- a/src/index_entry.rs +++ b/src/index_entry.rs @@ -1,7 +1,7 @@ // Copyright 2021 Colin Finck <colin@reactos.org> // SPDX-License-Identifier: GPL-2.0-or-later -use crate::error::Result; +use crate::error::{NtfsError, Result}; use crate::file::NtfsFile; use crate::file_reference::NtfsFileReference; use crate::indexes::{ @@ -21,7 +21,7 @@ use core::ops::Range; use memoffset::offset_of; /// Size of all [`IndexEntryHeader`] fields plus some reserved bytes. -const INDEX_ENTRY_HEADER_SIZE: i64 = 16; +const INDEX_ENTRY_HEADER_SIZE: usize = 16; #[repr(C, packed)] struct IndexEntryHeader { @@ -70,7 +70,7 @@ where } } - pub(crate) fn to_entry<'s>(&self, slice: &'s [u8]) -> NtfsIndexEntry<'s, E> { + pub(crate) fn to_entry<'s>(&self, slice: &'s [u8]) -> Result<NtfsIndexEntry<'s, E>> { NtfsIndexEntry::new(&slice[self.range.clone()], self.position) } } @@ -89,13 +89,18 @@ impl<'s, E> NtfsIndexEntry<'s, E> where E: NtfsIndexEntryType, { - pub(crate) fn new(slice: &'s [u8], position: u64) -> Self { + pub(crate) fn new(slice: &'s [u8], position: u64) -> Result<Self> { let entry_type = PhantomData; - Self { + + let mut entry = Self { slice, position, entry_type, - } + }; + entry.validate_size()?; + entry.slice = &entry.slice[..entry.index_entry_length() as usize]; + + Ok(entry) } pub fn data(&self) -> Option<Result<E::DataType>> @@ -110,10 +115,14 @@ where let end = start + self.data_length() as usize; let position = self.position + start as u64; - let data = iter_try!(E::DataType::data_from_slice( - &self.slice[start..end], - position - )); + let slice = self.slice.get(start..end); + let slice = iter_try!(slice.ok_or(NtfsError::InvalidIndexEntryDataRange { + position: self.position, + range: start..end, + size: self.slice.len() as u16 + })); + + let data = iter_try!(E::DataType::data_from_slice(slice, position)); Some(Ok(data)) } @@ -163,14 +172,18 @@ where return None; } - let start = INDEX_ENTRY_HEADER_SIZE as usize; + let start = INDEX_ENTRY_HEADER_SIZE; let end = start + self.key_length() as usize; let position = self.position + start as u64; - let key = iter_try!(E::KeyType::key_from_slice( - &self.slice[start..end], - position - )); + let slice = self.slice.get(start..end); + let slice = iter_try!(slice.ok_or(NtfsError::InvalidIndexEntryDataRange { + position: self.position, + range: start..end, + size: self.slice.len() as u16 + })); + + let key = iter_try!(E::KeyType::key_from_slice(slice, position)); Some(Ok(key)) } @@ -181,16 +194,27 @@ where /// Returns the Virtual Cluster Number (VCN) of the subnode of this Index Entry, /// or `None` if this Index Entry has no subnode. - pub fn subnode_vcn(&self) -> Option<Vcn> { + pub fn subnode_vcn(&self) -> Option<Result<Vcn>> { if !self.flags().contains(NtfsIndexEntryFlags::HAS_SUBNODE) { return None; } - // Get the subnode VCN from the very end of the Index Entry. - let start = self.index_entry_length() as usize - mem::size_of::<Vcn>(); - let vcn = Vcn::from(LittleEndian::read_i64(&self.slice[start..])); - - Some(vcn) + // Get the subnode VCN from the very end of the Index Entry, but at least after the header. + let start = usize::max( + self.index_entry_length() as usize - mem::size_of::<Vcn>(), + INDEX_ENTRY_HEADER_SIZE, + ); + let end = start + mem::size_of::<Vcn>(); + + let slice = self.slice.get(start..end); + let slice = iter_try!(slice.ok_or(NtfsError::InvalidIndexEntryDataRange { + position: self.position, + range: start..end, + size: self.slice.len() as u16 + })); + + let vcn = Vcn::from(LittleEndian::read_i64(slice)); + Some(Ok(vcn)) } /// Returns an [`NtfsFile`] for the file referenced by this index entry. @@ -201,6 +225,26 @@ where { self.file_reference().to_file(ntfs, fs) } + + fn validate_size(&self) -> Result<()> { + if self.slice.len() < INDEX_ENTRY_HEADER_SIZE { + return Err(NtfsError::InvalidIndexEntrySize { + position: self.position, + expected: INDEX_ENTRY_HEADER_SIZE as u16, + actual: self.slice.len() as u16, + }); + } + + if self.index_entry_length() as usize > self.slice.len() { + return Err(NtfsError::InvalidIndexEntrySize { + position: self.position, + expected: self.index_entry_length(), + actual: self.slice.len() as u16, + }); + } + + Ok(()) + } } #[derive(Clone, Debug)] @@ -239,7 +283,7 @@ impl<E> Iterator for IndexNodeEntryRanges<E> where E: NtfsIndexEntryType, { - type Item = IndexEntryRange<E>; + type Item = Result<IndexEntryRange<E>>; fn next(&mut self) -> Option<Self::Item> { if self.range.is_empty() { @@ -249,7 +293,7 @@ where // Get the current entry. let start = self.range.start; let position = self.position; - let entry = NtfsIndexEntry::<E>::new(&self.data[start..], position); + let entry = iter_try!(NtfsIndexEntry::<E>::new(&self.data[start..], position)); let end = start + entry.index_entry_length() as usize; if entry.flags().contains(NtfsIndexEntryFlags::LAST_ENTRY) { @@ -263,7 +307,7 @@ where self.position += entry.index_entry_length() as u64; } - Some(IndexEntryRange::new(start..end, position)) + Some(Ok(IndexEntryRange::new(start..end, position))) } } @@ -297,7 +341,7 @@ impl<'s, E> Iterator for NtfsIndexNodeEntries<'s, E> where E: NtfsIndexEntryType, { - type Item = NtfsIndexEntry<'s, E>; + type Item = Result<NtfsIndexEntry<'s, E>>; fn next(&mut self) -> Option<Self::Item> { if self.slice.is_empty() { @@ -305,7 +349,7 @@ where } // Get the current entry. - let entry = NtfsIndexEntry::new(self.slice, self.position); + let entry = iter_try!(NtfsIndexEntry::new(self.slice, self.position)); if entry.flags().contains(NtfsIndexEntryFlags::LAST_ENTRY) { // This is the last entry. @@ -319,7 +363,7 @@ where self.position += bytes_to_advance as u64; } - Some(entry) + Some(Ok(entry)) } } |