fix: ABI decoder crashing on certain inputs

packages/fuels-core/src/codec/abi_decoder.rs

@@ -88,6 +88,7 @@ mod tests {
         constants::WORD_SIZE,
         types::{enum_variants::EnumVariants, errors::Error, StaticStringToken},
     };
+    use ParamType::*;
 
     #[test]
     fn decode_int() -> Result<()> {
@@ -510,6 +511,97 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    pub fn division_by_zero() {
+        let result = ABIDecoder::default().decode(&Vector(Box::new(Array(Box::new(U16), 0))), &[]);
+        assert!(matches!(result, Err(Error::InvalidType(_))));
+    }
+
+    #[test]
+    pub fn multiply_overflow_enum() {
+        let result = ABIDecoder::default().decode(
+            &Enum {
+                variants: EnumVariants {
+                    param_types: vec![
+                        Array(Box::new(Array(Box::new(RawSlice), 8)), 576469587185895432),
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                        B256,
+                    ],
+                },
+                generics: vec![U16],
+            },
+            &[0, 8, 8, 8, 9, 8, 0, 8, 8, 8, 8, 8, 15, 8, 8, 8],
+        );
+        assert!(matches!(result, Err(Error::InvalidData(_))));
+    }
+
+    #[test]
+    pub fn multiply_overflow_vector() {
+        let result = ABIDecoder::default().decode(
+            &Vector(Box::new(Array(Box::new(Unit), 2308103648053880071))),
+            &[8, 8, 10, 7, 229, 8, 8, 8],
+        );
+        assert!(matches!(result, Err(Error::InvalidData(_))));
+    }
+
+    #[test]
+    pub fn multiply_overflow_arith() {
+        let mut typ: ParamType = U16;
+        for _ in 0..50 {
+            typ = Array(Box::new(typ), 8);
+        }
+        let result = ABIDecoder::default().decode(
+            &Enum {
+                variants: EnumVariants {
+                    param_types: vec![typ],
+                },
+                generics: vec![U16],
+            },
+            &[0, 8, 8, 51, 51, 51, 51, 51, 51, 51, 3, 8, 15, 8, 8, 8],
+        );
+        assert!(matches!(result, Err(Error::InvalidData(_))));
+    }
+
+    #[test]
+    pub fn capacity_overflow() {
+        let result = ABIDecoder::default().decode(
+            &Array(
+                Box::new(Array(Box::new(Tuple(vec![])), 7638104972323651592)),
+                242,
+            ),
+            &[13, 0, 1, 0, 0, 106, 242, 8],
+        );
+        dbg!(&result);
+        assert!(matches!(result, Err(Error::InvalidType(_))));
+    }
+
+    #[test]
+    pub fn stack_overflow() {
+        let mut typ: ParamType = U16;
+        for _ in 0..13500 {
+            typ = Vector(Box::new(typ));
+        }
+        let result = ABIDecoder::default().decode(&typ, &[8, 9, 9, 9, 9, 9, 9, 9]);
+        assert!(matches!(result, Err(Error::InvalidType(_))));
+    }
+
+    #[test]
+    pub fn capacity_maloc() {
+        let result = ABIDecoder::default().decode(
+            &Array(Box::new(U8), 72340198607880449),
+            &[8, 8, 7, 252, 201, 8, 8, 8],
+        );
+        assert!(matches!(result, Err(Error::InvalidData(_))));
+    }
+
     #[test]
     fn max_depth_surpassed() {
         const MAX_DEPTH: usize = 2;

packages/fuels-core/src/codec/abi_decoder/bounded_decoder.rs

@@ -1,4 +1,4 @@
-use std::{convert::TryInto, str};
+use std::{convert::TryInto, fmt, str};
 
 use fuel_types::bytes::padded_len_usize;
 
@@ -19,6 +19,7 @@ use crate::{
 pub(crate) struct BoundedDecoder {
     depth_tracker: CounterWithLimit,
     token_tracker: CounterWithLimit,
+    config: DecoderConfig,
 }
 
 const U128_BYTES_SIZE: usize = 2 * WORD_SIZE;
@@ -32,11 +33,12 @@ impl BoundedDecoder {
         Self {
             depth_tracker,
             token_tracker,
+            config,
         }
     }
 
     pub(crate) fn decode(&mut self, param_type: &ParamType, bytes: &[u8]) -> Result<Token> {
-        Self::is_type_decodable(param_type)?;
+        self.is_type_decodable(param_type)?;
         Ok(self.decode_param(param_type, bytes)?.token)
     }
 
@@ -46,18 +48,19 @@ impl BoundedDecoder {
         bytes: &[u8],
     ) -> Result<Vec<Token>> {
         for param_type in param_types {
-            Self::is_type_decodable(param_type)?;
+            self.is_type_decodable(param_type)?;
         }
         let (tokens, _) = self.decode_params(param_types, bytes)?;
 
         Ok(tokens)
     }
 
-    fn is_type_decodable(param_type: &ParamType) -> Result<()> {
+    fn is_type_decodable(&self, param_type: &ParamType) -> Result<()> {
         if param_type.contains_nested_heap_types() {
             Err(error!(
                 InvalidType,
-                "Type {param_type:?} contains nested heap types (`Vec` or `Bytes`), this is not supported."
+                "Type {:?} contains nested heap types (`Vec` or `Bytes`), this is not supported.",
+                DebugWithDepth::new(param_type, self.config.max_depth)
             ))
         } else {
             Ok(())
@@ -308,13 +311,14 @@ impl BoundedDecoder {
     /// * `data`: slice of encoded data on whose beginning we're expecting an encoded enum
     /// * `variants`: all types that this particular enum type could hold
     fn decode_enum(&mut self, bytes: &[u8], variants: &EnumVariants) -> Result<Decoded> {
-        let enum_width = variants.compute_encoding_width_of_enum();
+        let enum_width = variants.compute_encoding_width_of_enum()?;
 
         let discriminant = peek_u32(bytes)? as u8;
         let selected_variant = variants.param_type_of_variant(discriminant)?;
 
-        let words_to_skip = enum_width - selected_variant.compute_encoding_width();
-        let enum_content_bytes = skip(bytes, words_to_skip * WORD_SIZE)?;
+        let words_to_skip = enum_width - selected_variant.compute_encoding_width()?;
+        let bytes_to_skip = words_to_skip .checked_mul(WORD_SIZE).ok_or_else(|| error!(InvalidData, "attempt to multiply words_to_skip ({words_to_skip:?}) by WORD_SIZE ({WORD_SIZE:?}) with overflow"))?;
+        let enum_content_bytes = skip(bytes, bytes_to_skip)?;
         let result = self.decode_token_in_enum(enum_content_bytes, variants, selected_variant)?;
 
         let selector = Box::new((discriminant, result.token, variants.clone()));
@@ -457,3 +461,90 @@ fn skip(slice: &[u8], num_bytes: usize) -> Result<&[u8]> {
         Ok(&slice[num_bytes..])
     }
 }
+
+/// Allows `Debug` formatting of arbitrary-depth nested `ParamTypes` by
+/// omitting the details of inner types if max depth is exceeded.
+pub(crate) struct DebugWithDepth<'a> {
+    param_type: &'a ParamType,
+    depth_left: usize,
+}
+
+impl<'a> DebugWithDepth<'a> {
+    pub(crate) fn new(param_type: &'a ParamType, depth_left: usize) -> Self {
+        Self {
+            param_type,
+            depth_left,
+        }
+    }
+
+    fn descend(&'a self, param_type: &'a ParamType) -> Self {
+        Self {
+            param_type,
+            depth_left: self.depth_left - 1,
+        }
+    }
+}
+
+impl<'a> fmt::Debug for DebugWithDepth<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.depth_left == 0 {
+            return write!(f, "...");
+        }
+
+        match &self.param_type {
+            ParamType::Array(inner, size) => f
+                .debug_tuple("Array")
+                .field(&self.descend(inner))
+                .field(&size)
+                .finish(),
+            ParamType::Struct { fields, generics } => f
+                .debug_struct("Struct")
+                .field(
+                    "fields",
+                    &fields
+                        .iter()
+                        .map(|field| self.descend(field))
+                        .collect::<Vec<_>>(),
+                )
+                .field(
+                    "generics",
+                    &generics
+                        .iter()
+                        .map(|generic| self.descend(generic))
+                        .collect::<Vec<_>>(),
+                )
+                .finish(),
+            ParamType::Enum { variants, generics } => f
+                .debug_struct("Enum")
+                .field(
+                    "variants",
+                    &variants
+                        .param_types
+                        .iter()
+                        .map(|variant| self.descend(variant))
+                        .collect::<Vec<_>>(),
+                )
+                .field(
+                    "generics",
+                    &generics
+                        .iter()
+                        .map(|generic| self.descend(generic))
+                        .collect::<Vec<_>>(),
+                )
+                .finish(),
+            ParamType::Tuple(inner) => f
+                .debug_tuple("Tuple")
+                .field(
+                    &inner
+                        .iter()
+                        .map(|param_type| self.descend(param_type))
+                        .collect::<Vec<_>>(),
+                )
+                .finish(),
+            ParamType::Vector(inner) => {
+                f.debug_tuple("Vector").field(&self.descend(inner)).finish()
+            }
+            _ => write!(f, "{:?}", self.param_type),
+        }
+    }
+}

packages/fuels-core/src/codec/abi_encoder.rs

@@ -115,7 +115,7 @@ impl ABIEncoder {
         // Enums that contain only Units as variants have only their discriminant encoded.
         if !variants.only_units_inside() {
             let variant_param_type = variants.param_type_of_variant(*discriminant)?;
-            let padding_amount = variants.compute_padding_amount(variant_param_type);
+            let padding_amount = variants.compute_padding_amount(variant_param_type)?;
 
             encoded_enum.push(Data::Inline(vec![0; padding_amount]));
 

packages/fuels-core/src/types/enum_variants.rs

@@ -8,7 +8,7 @@ use crate::{
 
 #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 pub struct EnumVariants {
-    param_types: Vec<ParamType>,
+    pub param_types: Vec<ParamType>,
 }
 
 impl EnumVariants {
@@ -41,26 +41,31 @@ impl EnumVariants {
     }
 
     /// Calculates how many WORDs are needed to encode an enum.
-    pub fn compute_encoding_width_of_enum(&self) -> usize {
+    pub fn compute_encoding_width_of_enum(&self) -> Result<usize> {
         if self.only_units_inside() {
-            return ENUM_DISCRIMINANT_WORD_WIDTH;
+            return Ok(ENUM_DISCRIMINANT_WORD_WIDTH);
         }
         self.param_types()
             .iter()
             .map(|p| p.compute_encoding_width())
+            .collect::<Result<Vec<_>>>()?
+            .iter()
             .max()
             .map(|width| width + ENUM_DISCRIMINANT_WORD_WIDTH)
-            .expect(
-                "Will never panic because EnumVariants must have at least one variant inside it!",
-            )
+            .ok_or_else(|| {
+                error!(
+                    InvalidData,
+                    "EnumVariants was empty, must have at least one variant"
+                )
+            })
     }
 
     /// Determines the padding needed for the provided enum variant (based on the width of the
     /// biggest variant) and returns it.
-    pub fn compute_padding_amount(&self, variant_param_type: &ParamType) -> usize {
+    pub fn compute_padding_amount(&self, variant_param_type: &ParamType) -> Result<usize> {
         let biggest_variant_width =
-            self.compute_encoding_width_of_enum() - ENUM_DISCRIMINANT_WORD_WIDTH;
-        let variant_width = variant_param_type.compute_encoding_width();
-        (biggest_variant_width - variant_width) * WORD_SIZE
+            self.compute_encoding_width_of_enum()? - ENUM_DISCRIMINANT_WORD_WIDTH;
+        let variant_width = variant_param_type.compute_encoding_width()?;
+        Ok((biggest_variant_width - variant_width) * WORD_SIZE)
     }
 }