Buffer overflow CWE checks (#174)

src/cwe_checker_lib/src/analysis/pointer_inference/context/mod.rs

@@ -113,39 +113,109 @@ impl<'a> Context<'a> {
         }
     }
 
+    /// If the given `extern_symbol` is a call to a known allocation function
+    /// return the size of the memory object allocated by it.
+    ///
+    /// The function returns a `Top` element if the size could not be determined.
+    /// Known allocation functions: `malloc`, `realloc`, `calloc`.
+    fn get_allocation_size_of_alloc_call(
+        &self,
+        state: &State,
+        extern_symbol: &ExternSymbol,
+    ) -> ValueDomain {
+        let address_bytesize = self.project.get_pointer_bytesize();
+        let object_size = match extern_symbol.name.as_str() {
+            "malloc" => {
+                let size_parameter = extern_symbol.parameters.get(0).unwrap();
+                state
+                    .eval_parameter_arg(
+                        size_parameter,
+                        &self.project.stack_pointer_register,
+                        self.runtime_memory_image,
+                    )
+                    .unwrap_or_else(|_| Data::new_top(address_bytesize))
+            }
+            "realloc" => {
+                let size_parameter = extern_symbol.parameters.get(1).unwrap();
+                state
+                    .eval_parameter_arg(
+                        size_parameter,
+                        &self.project.stack_pointer_register,
+                        self.runtime_memory_image,
+                    )
+                    .unwrap_or_else(|_| Data::new_top(address_bytesize))
+            }
+            "calloc" => {
+                let size_param1 = extern_symbol.parameters.get(0).unwrap();
+                let size_param2 = extern_symbol.parameters.get(1).unwrap();
+                let param1_value = state
+                    .eval_parameter_arg(
+                        size_param1,
+                        &self.project.stack_pointer_register,
+                        self.runtime_memory_image,
+                    )
+                    .unwrap_or_else(|_| Data::new_top(address_bytesize));
+                let param2_value = state
+                    .eval_parameter_arg(
+                        size_param2,
+                        &self.project.stack_pointer_register,
+                        self.runtime_memory_image,
+                    )
+                    .unwrap_or_else(|_| Data::new_top(address_bytesize));
+                param1_value.bin_op(BinOpType::IntMult, &param2_value)
+            }
+            _ => DataDomain::new_top(address_bytesize),
+        };
+        match object_size {
+            Data::Value(val) => val,
+            _ => ValueDomain::new_top(address_bytesize),
+        }
+    }
+
     /// Add a new abstract object and a pointer to it in the return register of an extern call.
     /// This models the behaviour of `malloc`-like functions,
     /// except that we cannot represent possible `NULL` pointers as return values yet.
     fn add_new_object_in_call_return_register(
         &self,
-        mut state: State,
+        state: &State,
+        mut new_state: State,
         call: &Term<Jmp>,
         extern_symbol: &ExternSymbol,
     ) -> State {
+        let address_bytesize = self.project.get_pointer_bytesize();
+        let object_size = self.get_allocation_size_of_alloc_call(&state, extern_symbol);
+
         match extern_symbol.get_unique_return_register() {
             Ok(return_register) => {
                 let object_id = AbstractIdentifier::new(
                     call.tid.clone(),
                     AbstractLocation::from_var(return_register).unwrap(),
                 );
-                let address_bytesize = self.project.get_pointer_bytesize();
-                state.memory.add_abstract_object(
+                new_state.memory.add_abstract_object(
                     object_id.clone(),
                     Bitvector::zero(apint::BitWidth::from(address_bytesize)).into(),
                     super::object::ObjectType::Heap,
                     address_bytesize,
                 );
+                new_state.memory.set_lower_index_bound(
+                    &object_id,
+                    &Bitvector::zero(address_bytesize.into()).into(),
+                );
+                new_state.memory.set_upper_index_bound(
+                    &object_id,
+                    &(object_size - Bitvector::one(address_bytesize.into()).into()),
+                );
                 let pointer = PointerDomain::new(
                     object_id,
                     Bitvector::zero(apint::BitWidth::from(address_bytesize)).into(),
                 );
-                state.set_register(return_register, pointer.into());
-                state
+                new_state.set_register(return_register, pointer.into());
+                new_state
             }
             Err(err) => {
                 // We cannot track the new object, since we do not know where to store the pointer to it.
                 self.log_debug(Err(err), Some(&call.tid));
-                state
+                new_state
             }
         }
     }
@@ -254,6 +324,51 @@ impl<'a> Context<'a> {
         }
     }
 
+    /// Check whether a parameter of a call to an extern symbol may point outside of the bounds of a memory object.
+    /// If yes, generate a CWE-warning,
+    /// since the pointer may be used for an out-of-bounds memory access by the function.
+    fn check_parameter_register_for_out_of_bounds_pointer(
+        &self,
+        state: &State,
+        call: &Term<Jmp>,
+        extern_symbol: &ExternSymbol,
+    ) {
+        for parameter in extern_symbol.parameters.iter() {
+            match state.eval_parameter_arg(
+                parameter,
+                &self.project.stack_pointer_register,
+                &self.runtime_memory_image,
+            ) {
+                Ok(data) => {
+                    if state.pointer_contains_out_of_bounds_target(&data, self.runtime_memory_image)
+                    {
+                        let warning = CweWarning {
+                            name: "CWE119".to_string(),
+                            version: VERSION.to_string(),
+                            addresses: vec![call.tid.address.clone()],
+                            tids: vec![format!("{}", call.tid)],
+                            symbols: Vec::new(),
+                            other: Vec::new(),
+                            description: format!(
+                                "(Buffer Overflow) Call to {} at {} may access out-of-bounds memory",
+                                extern_symbol.name,
+                                call.tid.address
+                            ),
+                        };
+                        let _ = self.log_collector.send(LogThreadMsg::Cwe(warning));
+                    }
+                }
+                Err(err) => self.log_debug(
+                    Err(err.context(format!(
+                        "Function parameter {:?} could not be evaluated",
+                        parameter
+                    ))),
+                    Some(&call.tid),
+                ),
+            }
+        }
+    }
+
     /// Check whether the jump is an indirect call whose target evaluates to a *Top* value in the given state.
     fn is_indirect_call_with_top_target(&self, state: &State, call: &Term<Jmp>) -> bool {
         match &call.term {
@@ -277,7 +392,7 @@ impl<'a> Context<'a> {
         let stack_register = &self.project.stack_pointer_register;
         let stack_pointer = state_before_call.get_register(stack_register);
         match self.project.cpu_architecture.as_str() {
-            "x86" | "x86_64" => {
+            "x86" | "x86_32" | "x86_64" => {
                 let offset = Bitvector::from_u64(stack_register.size.into())
                     .into_truncate(apint::BitWidth::from(stack_register.size))
                     .unwrap();

src/cwe_checker_lib/src/analysis/pointer_inference/context/trait_impls.rs

@@ -32,6 +32,36 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
             };
             let _ = self.log_collector.send(LogThreadMsg::Cwe(warning));
         }
+        // check for out-of-bounds memory access
+        if state.contains_out_of_bounds_mem_access(&def.term, self.runtime_memory_image) {
+            let (warning_name, warning_description) = match def.term {
+                Def::Load { .. } => (
+                    "CWE125",
+                    format!(
+                        "(Out-of-bounds Read) Memory load at {} may be out of bounds",
+                        def.tid.address
+                    ),
+                ),
+                Def::Store { .. } => (
+                    "CWE787",
+                    format!(
+                        "(Out-of-bounds Write) Memory write at {} may be out of bounds",
+                        def.tid.address
+                    ),
+                ),
+                Def::Assign { .. } => panic!(),
+            };
+            let warning = CweWarning {
+                name: warning_name.to_string(),
+                version: VERSION.to_string(),
+                addresses: vec![def.tid.address.clone()],
+                tids: vec![format!("{}", def.tid)],
+                symbols: Vec::new(),
+                other: Vec::new(),
+                description: warning_description,
+            };
+            let _ = self.log_collector.send(LogThreadMsg::Cwe(warning));
+        }
 
         match &def.term {
             Def::Store { address, value } => {
@@ -59,8 +89,7 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
     }
 
     /// Update the state according to the effects of the given `Jmp` term.
-    /// Right now the state is not changed,
-    /// as specialization for conditional jumps is not implemented yet.
+    /// Right now the state is not changed.
     fn update_jump(
         &self,
         value: &State,
@@ -106,8 +135,14 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
                 // Note that this may lead to analysis errors if the function uses another calling convention.
                 callee_state.remove_callee_saved_register(cconv);
             }
+
+            // Set the lower index bound for the caller stack frame.
+            callee_state
+                .memory
+                .set_lower_index_bound(&state.stack_id, &stack_offset_adjustment);
             // Replace the caller stack ID with one determined by the call instruction.
-            // This has to be done *before* adding the new callee stack id to avoid confusing caller and callee stack ids in case of recursive calls.
+            // This has to be done *before* adding the new callee stack id
+            // to avoid confusing caller and callee stack ids in case of recursive calls.
             callee_state.replace_abstract_id(
                 &state.stack_id,
                 &new_caller_stack_id,
@@ -245,6 +280,12 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
         // remove non-referenced objects from the state
         state_after_return.remove_unreferenced_objects();
 
+        // remove the lower index bound of the stack frame
+        state_after_return.memory.set_lower_index_bound(
+            original_caller_stack_id,
+            &IntervalDomain::new_top(self.project.stack_pointer_register.size),
+        );
+
         Some(state_after_return)
     }
 
@@ -265,6 +306,8 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
         };
         let mut new_state = state.clone();
         if let Some(extern_symbol) = self.extern_symbol_map.get(call_target) {
+            // Generate a CWE-message if some argument is an out-of-bounds pointer.
+            self.check_parameter_register_for_out_of_bounds_pointer(state, call, extern_symbol);
             // Clear non-callee-saved registers from the state.
             let cconv = extern_symbol.get_calling_convention(&self.project);
             new_state.clear_non_callee_saved_register(&cconv.callee_saved_register[..]);
@@ -276,6 +319,7 @@ impl<'a> crate::analysis::forward_interprocedural_fixpoint::Context<'a> for Cont
             match extern_symbol.name.as_str() {
                 malloc_like_fn if self.allocation_symbols.iter().any(|x| x == malloc_like_fn) => {
                     Some(self.add_new_object_in_call_return_register(
+                        state,
                         new_state,
                         call,
                         extern_symbol,

src/cwe_checker_lib/src/analysis/pointer_inference/mod.rs

@@ -118,7 +118,17 @@ impl<'a> PointerInference<'a> {
                 if let Some(start_node_index) =
                     tid_to_graph_indices_map.get(&(block_tid, sub_tid.clone()))
                 {
-                    Some((sub_tid.clone(), *start_node_index))
+                    // We only add entry points that are also control flow graph roots
+                    if context
+                        .graph
+                        .neighbors_directed(*start_node_index, Direction::Incoming)
+                        .next()
+                        .is_none()
+                    {
+                        Some((sub_tid.clone(), *start_node_index))
+                    } else {
+                        None
+                    }
                 } else {
                     None
                 }

src/cwe_checker_lib/src/analysis/pointer_inference/object.rs

@@ -49,6 +49,14 @@ pub struct AbstractObjectInfo {
     type_: Option<ObjectType>,
     /// The actual content of the memory object
     memory: MemRegion<Data>,
+    /// The smallest index still contained in the memory region.
+    /// A `Top` value represents an unknown bound.
+    /// The bound is not enforced, i.e. reading and writing to indices violating the bound is still allowed.
+    lower_index_bound: BitvectorDomain,
+    /// The largest index still contained in the memory region.
+    /// A `Top` value represents an unknown bound.
+    /// The bound is not enforced, i.e. reading and writing to indices violating the bound is still allowed.
+    upper_index_bound: BitvectorDomain,
 }
 
 impl AbstractObjectInfo {
@@ -60,6 +68,56 @@ impl AbstractObjectInfo {
             state: Some(ObjectState::Alive),
             type_: Some(type_),
             memory: MemRegion::new(address_bytesize),
+            lower_index_bound: BitvectorDomain::Top(address_bytesize),
+            upper_index_bound: BitvectorDomain::Top(address_bytesize),
+        }
+    }
+
+    /// Set the lower index bound that is still considered to be contained in the abstract object.
+    pub fn set_lower_index_bound(&mut self, lower_bound: BitvectorDomain) {
+        self.lower_index_bound = lower_bound;
+    }
+
+    /// Set the upper index bound that is still considered to be contained in the abstract object.
+    pub fn set_upper_index_bound(&mut self, upper_bound: BitvectorDomain) {
+        self.upper_index_bound = upper_bound;
+    }
+
+    /// Check whether a memory access to the abstract object at the given offset
+    /// and with the given size of the accessed value is contained in the bounds of the memory object.
+    /// If `offset` contains more than one possible index value,
+    /// then only return `true` if the access is contained in the abstract object for all possible offset values.
+    pub fn access_contained_in_bounds(&self, offset: &ValueDomain, size: ByteSize) -> bool {
+        if let Ok(offset_interval) = offset.try_to_interval() {
+            if let Ok(lower_bound) = self.lower_index_bound.try_to_bitvec() {
+                if lower_bound.checked_sgt(&offset_interval.start).unwrap() {
+                    return false;
+                }
+            }
+            if let Ok(upper_bound) = self.upper_index_bound.try_to_bitvec() {
+                let mut size_as_bitvec = Bitvector::from_u64(u64::from(size));
+                match offset.bytesize().cmp(&size_as_bitvec.bytesize()) {
+                    std::cmp::Ordering::Less => size_as_bitvec.truncate(offset.bytesize()).unwrap(),
+                    std::cmp::Ordering::Greater => {
+                        size_as_bitvec.sign_extend(offset.bytesize()).unwrap()
+                    }
+                    std::cmp::Ordering::Equal => (),
+                }
+                let max_index = if let Some(val) = offset_interval
+                    .end
+                    .signed_add_overflow_checked(&size_as_bitvec)
+                {
+                    val - &Bitvector::one(offset.bytesize().into())
+                } else {
+                    return false; // The max index already causes an integer overflow
+                };
+                if upper_bound.checked_slt(&max_index).unwrap() {
+                    return false;
+                }
+            }
+            true
+        } else {
+            false
         }
     }
 
@@ -245,6 +303,8 @@ impl AbstractDomain for AbstractObjectInfo {
             state: same_or_none(&self.state, &other.state),
             type_: same_or_none(&self.type_, &other.type_),
             memory: self.memory.merge(&other.memory),
+            lower_index_bound: self.lower_index_bound.merge(&other.lower_index_bound),
+            upper_index_bound: self.upper_index_bound.merge(&other.upper_index_bound),
         }
     }
 
@@ -271,6 +331,14 @@ impl AbstractObjectInfo {
                 "type".to_string(),
                 serde_json::Value::String(format!("{:?}", self.type_)),
             ),
+            (
+                "lower_index_bound".to_string(),
+                serde_json::Value::String(format!("{}", self.lower_index_bound)),
+            ),
+            (
+                "upper_index_bound".to_string(),
+                serde_json::Value::String(format!("{}", self.upper_index_bound)),
+            ),
         ];
         let memory = self
             .memory
@@ -322,6 +390,8 @@ mod tests {
             state: Some(ObjectState::Alive),
             type_: Some(ObjectType::Heap),
             memory: MemRegion::new(ByteSize::new(8)),
+            lower_index_bound: Bitvector::from_u64(0).into(),
+            upper_index_bound: Bitvector::from_u64(99).into(),
         };
         AbstractObject(Arc::new(obj_info))
     }
@@ -442,4 +512,13 @@ mod tests {
                 .collect()
         );
     }
+
+    #[test]
+    fn access_contained_in_bounds() {
+        let object = new_abstract_object();
+        assert!(object.access_contained_in_bounds(&IntervalDomain::mock(0, 99), ByteSize::new(1)));
+        assert!(!object.access_contained_in_bounds(&IntervalDomain::mock(-1, -1), ByteSize::new(8)));
+        assert!(object.access_contained_in_bounds(&IntervalDomain::mock(92, 92), ByteSize::new(8)));
+        assert!(!object.access_contained_in_bounds(&IntervalDomain::mock(93, 93), ByteSize::new(8)));
+    }
 }

src/cwe_checker_lib/src/analysis/pointer_inference/object_list.rs

 use super::object::*;
 use super::{Data, ValueDomain};
-use crate::abstract_domain::*;
 use crate::prelude::*;
+use crate::{abstract_domain::*, utils::binary::RuntimeMemoryImage};
 use serde::{Deserialize, Serialize};
 use std::collections::{BTreeMap, BTreeSet};
 
@@ -23,13 +23,16 @@ pub struct AbstractObjectList {
 
 impl AbstractObjectList {
     /// Create a new abstract object list with just one abstract object corresponding to the stack.
-    /// The offset into the stack object will be set to zero.
+    ///
+    /// The offset into the stack object and the `upper_index_bound` of the stack object will be both set to zero.
+    /// This corresponds to the generic stack state at the start of a function.
     pub fn from_stack_id(
         stack_id: AbstractIdentifier,
         address_bytesize: ByteSize,
     ) -> AbstractObjectList {
         let mut objects = BTreeMap::new();
-        let stack_object = AbstractObject::new(ObjectType::Stack, address_bytesize);
+        let mut stack_object = AbstractObject::new(ObjectType::Stack, address_bytesize);
+        stack_object.set_upper_index_bound(Bitvector::zero(address_bytesize.into()).into());
         objects.insert(
             stack_id,
             (
@@ -68,6 +71,70 @@ impl AbstractObjectList {
         false
     }
 
+    /// Check whether a memory access at the given address (and accessing `size` many bytes)
+    /// may be an out-of-bounds memory access.
+    ///
+    /// Note that `Top` values as addresses are not marked as out-of-bounds,
+    /// since they are more likely due to analysis imprecision than to actual out-of-bounds access.
+    pub fn is_out_of_bounds_mem_access(
+        &self,
+        address: &Data,
+        size: ByteSize,
+        global_data: &RuntimeMemoryImage,
+    ) -> bool {
+        match address {
+            Data::Value(value) => {
+                if let Ok((start, end)) = value.try_to_offset_interval() {
+                    if start < 0 || end < start {
+                        return true;
+                    }
+                    return global_data
+                        .is_interval_readable(start as u64, end as u64 + u64::from(size) - 1)
+                        .is_err();
+                }
+            }
+            Data::Top(_) => (),
+            Data::Pointer(pointer) => {
+                for (id, offset) in pointer.targets() {
+                    let (object, base_offset) = self.objects.get(id).unwrap();
+                    let adjusted_offset = offset.clone() + base_offset.clone();
+                    if !adjusted_offset.is_top()
+                        && !object.access_contained_in_bounds(&adjusted_offset, size)
+                    {
+                        return true;
+                    }
+                }
+            }
+        }
+        false
+    }
+
+    /// Set the lower index bound for indices to be considered inside the memory object.
+    /// The bound is inclusive, i.e. the bound index itself is also considered to be inside the memory object.
+    ///
+    /// Any `bound` value other than a constant bitvector is interpreted as the memory object not having a lower bound.
+    pub fn set_lower_index_bound(&mut self, object_id: &AbstractIdentifier, bound: &ValueDomain) {
+        let (object, base_offset) = self.objects.get_mut(object_id).unwrap();
+        let bound = (bound.clone() + base_offset.clone())
+            .try_to_bitvec()
+            .map(|bitvec| bitvec.into())
+            .unwrap_or_else(|_| BitvectorDomain::new_top(bound.bytesize()));
+        object.set_lower_index_bound(bound);
+    }
+
+    /// Set the upper index bound for indices to be considered inside the memory object.
+    /// The bound is inclusive, i.e. the bound index itself is also considered to be inside the memory object.
+    ///
+    /// Any `bound` value other than a constant bitvector is interpreted as the memory object not having an upper bound.
+    pub fn set_upper_index_bound(&mut self, object_id: &AbstractIdentifier, bound: &ValueDomain) {
+        let (object, base_offset) = self.objects.get_mut(object_id).unwrap();
+        let bound = (bound.clone() + base_offset.clone())
+            .try_to_bitvec()
+            .map(|bitvec| bitvec.into())
+            .unwrap_or_else(|_| BitvectorDomain::new_top(bound.bytesize()));
+        object.set_upper_index_bound(bound);
+    }
+
     /// Get the value at a given address.
     /// If the address is not unique, merge the value of all possible addresses.
     ///

src/cwe_checker_lib/src/analysis/pointer_inference/state/access_handling.rs

@@ -257,6 +257,60 @@ impl State {
         }
     }
 
+    /// Returns `true` if the given `Def` is a load or store instruction
+    /// which may access a memory object outside its bounds.
+    pub fn contains_out_of_bounds_mem_access(
+        &self,
+        def: &Def,
+        global_data: &RuntimeMemoryImage,
+    ) -> bool {
+        let (raw_address, size) = match def {
+            Def::Load { address, var } => (self.eval(address), var.size),
+            Def::Store { address, value } => (self.eval(address), value.bytesize()),
+            _ => return false,
+        };
+        if self.is_stack_pointer_with_nonnegative_offset(&raw_address) {
+            // Access to a parameter or the return address of the function
+            return false;
+        }
+        let address = self.adjust_pointer_for_read(&raw_address);
+        self.memory
+            .is_out_of_bounds_mem_access(&address, size, global_data)
+    }
+
+    /// Returns `true` if `data` is a pointer pointing outside of the bounds of a memory buffer.
+    /// Does not check whether `data` may represent an out-of-bounds access to global memory,
+    /// since this function assumes that all absolute values are not pointers.
+    pub fn pointer_contains_out_of_bounds_target(
+        &self,
+        data: &Data,
+        global_data: &RuntimeMemoryImage,
+    ) -> bool {
+        let data = self.adjust_pointer_for_read(data);
+        matches!(data, Data::Pointer(_))
+            && self
+                .memory
+                .is_out_of_bounds_mem_access(&data, ByteSize::new(1), global_data)
+    }
+
+    /// Return `true` if `data` is a pointer to the current stack frame with a constant positive address,
+    /// i.e. if it accesses a stack parameter (or the return-to address for x86) of the current function.
+    pub fn is_stack_pointer_with_nonnegative_offset(&self, data: &Data) -> bool {
+        if let Data::Pointer(pointer) = data {
+            if pointer.targets().len() == 1 {
+                let (target, offset) = pointer.targets().iter().next().unwrap();
+                if *target == self.stack_id {
+                    if let Ok(offset_val) = offset.try_to_offset() {
+                        if offset_val >= 0 {
+                            return true;
+                        }
+                    }
+                }
+            }
+        }
+        false
+    }
+
     /// If  the given address is a positive stack offset and `self.caller_stack_ids` is non-empty,
     /// i.e. it is an access to the caller stack, return the offset.
     ///

src/cwe_checker_lib/src/analysis/pointer_inference/state/mod.rs

@@ -345,6 +345,24 @@ impl State {
                 (Data::Value(old_value), Data::Value(result_value)) => {
                     self.set_register(var, old_value.intersect(&result_value)?.into())
                 }
+                (Data::Pointer(old_pointer), Data::Pointer(result_pointer)) => {
+                    let mut specialized_targets = BTreeMap::new();
+                    for (id, offset) in result_pointer.targets() {
+                        if let Some(old_offset) = old_pointer.targets().get(id) {
+                            if let Ok(specialized_offset) = old_offset.intersect(offset) {
+                                specialized_targets.insert(id.clone(), specialized_offset);
+                            }
+                        }
+                    }
+                    if !specialized_targets.is_empty() {
+                        self.set_register(
+                            var,
+                            PointerDomain::with_targets(specialized_targets).into(),
+                        );
+                    } else {
+                        return Err(anyhow!("Pointer with no targets is unsatisfiable"));
+                    }
+                }
                 (Data::Top(_), result) => self.set_register(var, result),
                 _ => (),
             }
@@ -421,25 +439,21 @@ impl State {
     ) -> Result<(), Error> {
         match op {
             BinOpType::IntAdd => {
-                if let Ok(bitvec) = self.eval(lhs).try_to_bitvec() {
-                    let intermediate_result = result.clone() - bitvec.into();
-                    self.specialize_by_expression_result(rhs, intermediate_result)?;
-                }
-                if let Ok(bitvec) = self.eval(rhs).try_to_bitvec() {
-                    let intermediate_result = result - bitvec.into();
-                    self.specialize_by_expression_result(lhs, intermediate_result)?;
-                }
+                let intermediate_result = result.clone() - self.eval(lhs);
+                self.specialize_by_expression_result(rhs, intermediate_result)?;
+
+                let intermediate_result = result - self.eval(rhs);
+                self.specialize_by_expression_result(lhs, intermediate_result)?;
+
                 return Ok(());
             }
             BinOpType::IntSub => {
-                if let Ok(bitvec) = self.eval(lhs).try_to_bitvec() {
-                    let intermediate_result: Data = Data::from(bitvec) - result.clone();
-                    self.specialize_by_expression_result(rhs, intermediate_result)?;
-                }
-                if let Ok(bitvec) = self.eval(rhs).try_to_bitvec() {
-                    let intermediate_result = result + bitvec.into();
-                    self.specialize_by_expression_result(lhs, intermediate_result)?;
-                }
+                let intermediate_result: Data = self.eval(lhs) - result.clone();
+                self.specialize_by_expression_result(rhs, intermediate_result)?;
+
+                let intermediate_result = result + self.eval(rhs);
+                self.specialize_by_expression_result(lhs, intermediate_result)?;
+
                 return Ok(());
             }
             _ => (),

src/cwe_checker_lib/src/analysis/pointer_inference/state/tests.rs

@@ -497,6 +497,25 @@ fn specialize_by_expression_results() {
         .specialize_by_expression_result(&Expression::var("RAX"), Bitvector::from_i64(-20).into());
     assert!(x.is_err());
 
+    let mut state = base_state.clone();
+    let abstract_id = AbstractIdentifier::new(
+        Tid::new("heap_obj"),
+        AbstractLocation::from_var(&register("RAX")).unwrap(),
+    );
+    state.set_register(
+        &register("RAX"),
+        PointerDomain::new(abstract_id.clone(), IntervalDomain::mock(0, 50)).into(),
+    );
+    let x = state.specialize_by_expression_result(
+        &Expression::var("RAX"),
+        PointerDomain::new(abstract_id.clone(), IntervalDomain::mock(20, 70)).into(),
+    );
+    assert!(x.is_ok());
+    assert_eq!(
+        state.get_register(&register("RAX")),
+        PointerDomain::new(abstract_id, IntervalDomain::mock(20, 50)).into()
+    );
+
     // Expr = Const
     let mut state = base_state.clone();
     let x = state.specialize_by_expression_result(
@@ -989,3 +1008,61 @@ fn specialize_by_unsigned_comparison_op() {
         IntervalDomain::mock_with_bounds(Some(-19), -5, -1, None).into()
     );
 }
+
+#[test]
+fn stack_pointer_with_nonnegative_offset() {
+    let state = State::new(&register("RSP"), Tid::new("func_tid"));
+    let pointer = PointerDomain::new(state.stack_id.clone(), Bitvector::from_i64(-1).into()).into();
+    assert!(!state.is_stack_pointer_with_nonnegative_offset(&pointer));
+    let pointer = PointerDomain::new(state.stack_id.clone(), Bitvector::from_i64(5).into()).into();
+    assert!(state.is_stack_pointer_with_nonnegative_offset(&pointer));
+    let pointer = PointerDomain::new(state.stack_id.clone(), IntervalDomain::mock(2, 3)).into();
+    assert!(!state.is_stack_pointer_with_nonnegative_offset(&pointer)); // The offset is not a constant
+}
+
+#[test]
+fn out_of_bounds_access_recognition() {
+    let mut state = State::new(&register("RSP"), Tid::new("func_tid"));
+    let global_data = RuntimeMemoryImage::mock();
+    let heap_obj_id = new_id("heap_malloc", "RAX");
+    state.memory.add_abstract_object(
+        heap_obj_id.clone(),
+        Bitvector::from_u64(0).into(),
+        crate::analysis::pointer_inference::object::ObjectType::Heap,
+        ByteSize::new(8),
+    );
+    state
+        .memory
+        .set_lower_index_bound(&heap_obj_id, &Bitvector::from_u64(0).into());
+    state
+        .memory
+        .set_upper_index_bound(&heap_obj_id, &Bitvector::from_u64(7).into());
+
+    let pointer = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_i64(-1).into()).into();
+    assert!(state.pointer_contains_out_of_bounds_target(&pointer, &global_data));
+    let pointer = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(0).into()).into();
+    assert!(!state.pointer_contains_out_of_bounds_target(&pointer, &global_data));
+    let pointer = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(7).into()).into();
+    assert!(!state.pointer_contains_out_of_bounds_target(&pointer, &global_data));
+    let pointer = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(8).into()).into();
+    assert!(state.pointer_contains_out_of_bounds_target(&pointer, &global_data));
+
+    let address = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(0).into()).into();
+    state.set_register(&Variable::mock("RAX", 8), address);
+    let load_def = Def::load(
+        "tid",
+        Variable::mock("RBX", 8),
+        Expression::Var(Variable::mock("RAX", 8)),
+    );
+    assert!(!state.contains_out_of_bounds_mem_access(&load_def.term, &global_data));
+
+    let address = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(0).into()).into();
+    state.set_register(&Variable::mock("RAX", 8), address);
+    assert!(!state.contains_out_of_bounds_mem_access(&load_def.term, &global_data));
+    let address = PointerDomain::new(heap_obj_id.clone(), Bitvector::from_u64(1).into()).into();
+    state.set_register(&Variable::mock("RAX", 8), address);
+    assert!(state.contains_out_of_bounds_mem_access(&load_def.term, &global_data));
+    let address = PointerDomain::new(state.stack_id.clone(), Bitvector::from_u64(8).into()).into();
+    state.set_register(&Variable::mock("RAX", 8), address);
+    assert!(!state.contains_out_of_bounds_mem_access(&load_def.term, &global_data));
+}

src/cwe_checker_lib/src/intermediate_representation/bitvector.rs

@@ -37,6 +37,9 @@ pub trait BitvectorExtended: Sized {
     /// Returns an error for bitvectors larger than 8 bytes,
     /// since multiplication for them is not yet implemented in the [`apint`] crate.
     fn signed_mult_with_overflow_flag(&self, rhs: &Self) -> Result<(Self, bool), Error>;
+
+    /// Return the size in bytes of the bitvector.
+    fn bytesize(&self) -> ByteSize;
 }
 
 impl BitvectorExtended for Bitvector {
@@ -261,6 +264,11 @@ impl BitvectorExtended for Bitvector {
             }
         }
     }
+
+    /// Return the size in bytes of the bitvector.
+    fn bytesize(&self) -> ByteSize {
+        self.width().into()
+    }
 }
 
 #[cfg(test)]

src/cwe_checker_lib/src/intermediate_representation/term.rs

@@ -460,7 +460,7 @@ impl Project {
     pub fn get_standard_calling_convention(&self) -> Option<&CallingConvention> {
         self.calling_conventions
             .iter()
-            .find(|cconv| cconv.name == "__stdcall")
+            .find(|cconv| cconv.name == "__stdcall" || cconv.name == "__cdecl")
     }
 }
 

src/cwe_checker_lib/src/lib.rs

@@ -66,7 +66,7 @@ mod prelude {
     pub use apint::Width;
     pub use serde::{Deserialize, Serialize};
 
-    pub use crate::intermediate_representation::{Bitvector, ByteSize};
+    pub use crate::intermediate_representation::{Bitvector, BitvectorExtended, ByteSize};
     pub use crate::intermediate_representation::{Term, Tid};
     pub use crate::AnalysisResults;
     pub use anyhow::{anyhow, Error};

test/artificial_samples/SConstruct

@@ -78,9 +78,9 @@ def which(pgm):
 
 
 def optimize(filename):
-    optimize_me = []
+    optimize_me = ["cwe_119.c"]
     if filename in optimize_me:
-        return ' -O3'
+        return ' -O1'
     else:
         return ' -O0'
 

test/artificial_samples/cwe_119.c

+#include <stdlib.h>
+#include <stdio.h>
+
+void set_array_elements(int* array) {
+    for(int i = 0; i<= 10; i++) {
+        array[i] = i*i; // Out-of-bounds write for arrays that are too small.
+    }
+}
+
+void print_array_sum(int* array) {
+    int sum = 0;
+    for(int i = 0; i<= 10; i++) {
+        sum += array[i]; // Out-of-bounds read for arrays that are too small.
+    }
+    printf("%d\n", sum);
+}
+
+int main() {
+    int* array = calloc(5, sizeof(int));
+    set_array_elements(array);
+    free(array);
+
+    array = malloc(5 * sizeof(int));
+    print_array_sum(array);
+
+    puts((void*) array - 1); // Parameter is an out-of-bounds pointer.
+    free(array);
+}
\ No newline at end of file

test/artificial_samples/cwe_125.c

-#include <stdio.h>
-#include <stdlib.h>
-
-int main(int argc, char **argv) {
-        int id_sequence[3];
-
-        id_sequence[0] = 123;
-        id_sequence[1] = 234;
-        id_sequence[2] = 345;
-        id_sequence[0] = id_sequence[3];
-}

test/artificial_samples/cwe_787.c

-#include <stdio.h>
-#include <stdlib.h>
-
-int main(int argc, char **argv) {
-        int id_sequence[3];
-
-        id_sequence[0] = 123;
-        id_sequence[1] = 234;
-        id_sequence[2] = 345;
-        id_sequence[3] = 678;
-}

test/src/lib.rs

@@ -202,6 +202,61 @@ mod tests {
 
     #[test]
     #[ignore]
+    fn cwe_119() {
+        let mut error_log = Vec::new();
+        let mut tests = all_test_cases("cwe_119", "Memory");
+
+        mark_architecture_skipped(&mut tests, "ppc64"); // Ghidra generates mangled function names here for some reason.
+        mark_architecture_skipped(&mut tests, "ppc64le"); // Ghidra generates mangled function names here for some reason.
+
+        mark_skipped(&mut tests, "x86", "gcc"); // Loss of stack register value since we do not track pointer alignment yet.
+
+        for test_case in tests {
+            let num_expected_occurences = 1;
+            if let Err(error) = test_case.run_test("[CWE119]", num_expected_occurences) {
+                error_log.push((test_case.get_filepath(), error));
+            }
+        }
+        if !error_log.is_empty() {
+            print_errors(error_log);
+            panic!();
+        }
+    }
+
+    #[test]
+    #[ignore]
+    fn cwe_125() {
+        let mut error_log = Vec::new();
+        let mut tests = all_test_cases("cwe_119", "Memory");
+
+        mark_skipped(&mut tests, "aarch64", "clang"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mips64", "gcc"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mips64el", "gcc"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mips", "clang"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mipsel", "clang"); // TODO: Check reason for failure!
+
+        mark_architecture_skipped(&mut tests, "ppc64"); // Ghidra generates mangled function names here for some reason.
+        mark_architecture_skipped(&mut tests, "ppc64le"); // Ghidra generates mangled function names here for some reason.
+
+        mark_skipped(&mut tests, "x86", "gcc"); // Loss of stack register value since we do not track pointer alignment yet.
+
+        mark_skipped(&mut tests, "x86", "clang"); // TODO: Check reason for failure!
+        mark_compiler_skipped(&mut tests, "mingw32-gcc"); // TODO: Check reason for failure!
+
+        for test_case in tests {
+            let num_expected_occurences = 1;
+            if let Err(error) = test_case.run_test("[CWE125]", num_expected_occurences) {
+                error_log.push((test_case.get_filepath(), error));
+            }
+        }
+        if !error_log.is_empty() {
+            print_errors(error_log);
+            panic!();
+        }
+    }
+
+    #[test]
+    #[ignore]
     fn cwe_190() {
         let mut error_log = Vec::new();
         let mut tests = all_test_cases("cwe_190", "CWE190");
@@ -509,4 +564,38 @@ mod tests {
             panic!();
         }
     }
+
+    #[test]
+    #[ignore]
+    fn cwe_787() {
+        let mut error_log = Vec::new();
+        let mut tests = all_test_cases("cwe_119", "Memory");
+
+        mark_skipped(&mut tests, "arm", "gcc"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mips64", "gcc"); // TODO: Check reason for failure!
+        mark_skipped(&mut tests, "mips64el", "gcc"); // TODO: Check reason for failure!
+
+        mark_architecture_skipped(&mut tests, "mips"); // TODO: Check reason for failure!
+        mark_architecture_skipped(&mut tests, "mipsel"); // TODO: Check reason for failure!
+
+        mark_architecture_skipped(&mut tests, "ppc64"); // Ghidra generates mangled function names here for some reason.
+        mark_architecture_skipped(&mut tests, "ppc64le"); // Ghidra generates mangled function names here for some reason.
+
+        mark_skipped(&mut tests, "ppc", "gcc"); // TODO: Check reason for failure!
+
+        mark_skipped(&mut tests, "x86", "gcc"); // Loss of stack register value since we do not track pointer alignment yet.
+
+        mark_compiler_skipped(&mut tests, "mingw32-gcc"); // TODO: Check reason for failure!
+
+        for test_case in tests {
+            let num_expected_occurences = 1;
+            if let Err(error) = test_case.run_test("[CWE787]", num_expected_occurences) {
+                error_log.push((test_case.get_filepath(), error));
+            }
+        }
+        if !error_log.is_empty() {
+            print_errors(error_log);
+            panic!();
+        }
+    }
 }