harden against dos with crafted input by limiting reserved vec/map size

src/demo/message/classinfo.rs

@@ -2,6 +2,7 @@ use bitstream_reader::{BitRead, BitReadSized, LittleEndian};
 
 use crate::demo::message::stringtable::log_base2;
 use crate::{ReadResult, Stream};
+use std::cmp::min;
 
 #[derive(BitReadSized, Debug)]
 pub struct ClassInfoEntry {
@@ -23,7 +24,7 @@ impl BitRead<LittleEndian> for ClassInfoMessage {
         let count: u16 = stream.read()?;
         let create: bool = stream.read()?;
         let entries = if !create {
-            let mut entries = Vec::with_capacity(count as usize);
+            let mut entries = Vec::with_capacity(min(count, 128) as usize);
             let bits = log_base2(count);
             for _ in 0..count {
                 entries.push(stream.read_sized(bits as usize)?);

src/demo/message/packetentities.rs

@@ -8,6 +8,7 @@ use crate::demo::parser::ParseBitSkip;
 use crate::demo::sendprop::{SendProp, SendPropDefinition, SendPropValue};
 use crate::{Parse, ParseError, ParserState, ReadResult, Result, Stream};
 use parse_display::{Display, FromStr};
+use std::cmp::min;
 use std::collections::HashMap;
 use std::fmt;
 use std::hint::unreachable_unchecked;
@@ -146,7 +147,7 @@ impl Parse for PacketEntitiesMessage {
         let updated_base_line = stream.read()?;
         let mut data = stream.read_bits(length as usize)?;
 
-        let mut entities = Vec::with_capacity(updated_entries as usize);
+        let mut entities = Vec::with_capacity(min(updated_entries, 128) as usize);
         let mut removed_entities = Vec::new();
 
         let mut last_index: i32 = -1;

src/demo/message/setconvar.rs

@@ -2,6 +2,7 @@ use bitstream_reader::{BitRead, BitReadSized, LittleEndian};
 
 use crate::demo::message::stringtable::log_base2;
 use crate::{ReadResult, Stream};
+use std::cmp::min;
 
 #[derive(Debug)]
 pub struct SetConVarMessage {
@@ -11,7 +12,7 @@ pub struct SetConVarMessage {
 impl BitRead<LittleEndian> for SetConVarMessage {
     fn read(stream: &mut Stream) -> ReadResult<Self> {
         let count: u8 = stream.read()?;
-        let mut vars: Vec<(String, String)> = Vec::with_capacity(count as usize);
+        let mut vars: Vec<(String, String)> = Vec::with_capacity(min(count, 128) as usize);
         for _ in 0..count {
             let key = stream
                 .read()

src/demo/message/stringtable.rs

@@ -7,6 +7,7 @@ use crate::demo::packet::stringtable::{
 };
 use crate::demo::parser::ParseBitSkip;
 use crate::{Parse, ParseError, ParserState, ReadResult, Result, Stream};
+use std::cmp::min;
 
 #[derive(Debug)]
 pub struct CreateStringTableMessage {
@@ -149,7 +150,7 @@ struct TableEntries {
 impl TableEntries {
     pub fn new(count: usize) -> Self {
         TableEntries {
-            entries: Vec::with_capacity(count),
+            entries: Vec::with_capacity(min(count, 128)),
             history: Vec::with_capacity(32),
         }
     }

src/demo/packet/datatable.rs

@@ -9,6 +9,7 @@ use parse_display::{Display, FromStr};
 use serde::{Deserialize, Serialize};
 use std::borrow::Borrow;
 use std::cell::{Cell, RefCell};
+use std::cmp::min;
 use std::fmt;
 use std::num::ParseIntError;
 use std::ops::Deref;
@@ -83,7 +84,7 @@ impl ParseSendTable {
         let prop_count = stream.read_int(10)?;
 
         let mut array_element_prop = None;
-        let mut props = Vec::with_capacity(prop_count);
+        let mut props = Vec::with_capacity(min(prop_count, 128));
 
         for prop_index in 0..prop_count {
             let definition_index = SendPropDefinitionIndex::new(table_index, prop_index);

src/demo/packet/stringtable.rs

@@ -4,6 +4,7 @@ use bitstream_reader::{BitRead, LittleEndian};
 
 use crate::demo::message::stringtable::StringTableMeta;
 use crate::{Parse, ParseError, ParserState, ReadResult, Result, Stream};
+use std::cmp::min;
 
 #[derive(BitRead, Clone, Copy, Debug)]
 pub struct FixedUserDataSize {
@@ -36,7 +37,7 @@ impl BitRead<LittleEndian> for StringTable {
     fn read(stream: &mut Stream) -> ReadResult<Self> {
         let name = stream.read()?;
         let entry_count = stream.read_int(16)?;
-        let mut entries = Vec::with_capacity(entry_count as usize);
+        let mut entries = Vec::with_capacity(min(entry_count, 128) as usize);
 
         for index in 0..entry_count {
             entries.push((index, stream.read()?))

src/demo/sendprop.rs

@@ -11,6 +11,7 @@ use crate::demo::packet::datatable::SendTableName;
 use crate::demo::parser::MalformedSendPropDefinitionError;
 use parse_display::Display;
 use serde::export::TryFrom;
+use std::cmp::min;
 use std::convert::TryInto;
 use std::fmt;
 use std::rc::Rc;
@@ -423,7 +424,7 @@ impl SendPropValue {
         ) + 1;
 
         let count = stream.read_int(num_bits as usize)?;
-        let mut values = Vec::with_capacity(count);
+        let mut values = Vec::with_capacity(min(count, 128));
 
         let child_definition = definition
             .array_property