falcon 0.2.0

A Binary Analysis Framework in Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216

//! A memory model for abstract interpretation
//!
//! This memory model wraps falcon::memory::paged::Memory and adds a `join`
//! method which operates over abstract values.

use error::*;
use memory::paged;
use memory;
use RC;
use types::Endian;
use std::fmt::Debug;


/// The `Value` trait must be implemented for abstract values operated over by
/// this memory model.
pub trait Value: memory::value::Value + Clone + Debug + Eq + PartialEq {
    /// Join this abstract value with another.
    fn join(&self, other: &Self) -> Result<Self>;

    /// Return an empty value.
    fn empty(bits: usize) -> Self;
}


/// A memory model for abstract interpretation.
#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct Memory<'m, V: Value>(paged::Memory<'m, V>);

impl<'m, V> Memory<'m, V> where V: Value {
    /// Create a new memory model for abstract interpretation.
    pub fn new(endian: Endian) -> Memory<'m, V> {
        Memory(paged::Memory::new(endian))
    }


    /// Create a new memory model for abstract interpretation with the given
    /// memory backing.
    pub fn new_with_backing(endian: Endian, backing: &'m memory::backing::Memory)
        -> Memory<'m, V> {
            Memory(paged::Memory::new_with_backing(endian, backing))
        }


    /// Store an abstract value at the given address.
    pub fn store(&mut self, address: u64, value: V) -> Result<()> {
        self.0.store(address, value)
    }


    /// Load an abstract value from the given address.
    pub fn load(&self, address: u64, bits: usize) -> Result<V> {
        Ok(match self.0.load(address, bits)? {
            Some(v) => v,
            None => V::empty(bits)
        })
    }


    /// Join this abstract memory moel with another.
    pub fn join(mut self, other: &Memory<V>) -> Result<Memory<'m, V>> {
        // for every page in the other memory
        for other_page in &other.0.pages {
            let page = match self.0.pages.get(&other_page.0) {
                // If this page exists in this memory
                Some(this_page) =>
                    // And the two pages are equivalent, clone this page.
                    // It's an RC, so should be a cheap clone.
                    if this_page == other_page.1 {
                        this_page.clone()
                    }
                    else {
                        // We're going to join cell by cell
                        let mut cells = Vec::new();
                        let other_cells = &other_page.1.cells;
                        let this_cells = &this_page.cells;
                        // for every cell
                        for i in 0..this_cells.len() {
                            // if the cells are equal, clone one and push it
                            if this_cells[i] == other_cells[i] {
                                cells.push(this_cells[i].clone());
                                continue;
                            }

                            // If both cells are values, and they're the same bit-size, join
                            // them and push the result
                            if let Some(this_value) = this_cells[i].as_ref()
                                                                   .and_then(|ref c| c.value()) {
                                if let Some(other_value) = other_cells[i].as_ref()
                                                                         .and_then(|ref c| c.value()) {
                                    if memory::value::Value::bits(this_value) == other_value.bits() {

                                        // join them and store the value
                                        let value = this_value.join(other_value)?;
                                        cells.push(Some(paged::MemoryCell::Value(value)));
                                        continue;
                                    }
                                }
                            }

                            let address = other_page.0 + i as u64;

                            let this_value = self.load(address, 8)?;
                            let other_value = other.load(address, 8)?;
                            cells.push(Some(paged::MemoryCell::Value(this_value.join(&other_value)?)));
                        }
                        RC::new(paged::Page::new_with_cells(cells))
                    },
                // This page does not exist here, clone other page
                None => other_page.1.clone()
            };
            self.0.pages.insert(*other_page.0, page);
        }
        Ok(self)
    }
}


#[cfg(test)]
mod memory_tests {
    use analysis::ai::kset::KSet;
    use analysis::ai::memory::Memory;
    use il;
    use types::Endian;

    #[test]
    fn ai_memory_big_endian() {
        let mut memory: Memory<KSet> = Memory::new(Endian::Big);

        let value = KSet::constant(il::const_(0xAABBCCDD, 32));

        memory.store(0x100, value.clone()).unwrap();

        let load_value = memory.load(0x100, 32).unwrap();

        assert_eq!(load_value, value);

        let load_0 = memory.load(0x100, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xAA, 8)));

        let load_0 = memory.load(0x101, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xBB, 8)));

        let load_0 = memory.load(0x102, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xCC, 8)));

        let load_0 = memory.load(0x103, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xDD, 8)));

        memory.store(0x102, KSet::constant(il::const_(0xFF, 8))).unwrap();

        let load_0 = memory.load(0x100, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xAA, 8)));

        let load_0 = memory.load(0x101, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xBB, 8)));

        let load_0 = memory.load(0x102, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xFF, 8)));

        let load_0 = memory.load(0x103, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xDD, 8)));

        assert_eq!(memory.load(0x100, 32).unwrap(), KSet::constant(il::const_(0xaabbffdd, 32)));

        let other_memory: Memory<KSet> = Memory::new(Endian::Big);
        let memory = memory.join(&other_memory).unwrap();

        assert_eq!(memory.load(0x100, 32).unwrap(), KSet::constant(il::const_(0xaabbffdd, 32)));        
    }

    #[test]
    fn ai_memory_little_endian() {
        let mut memory: Memory<KSet> = Memory::new(Endian::Little);

        let value = KSet::constant(il::const_(0xAABBCCDD, 32));

        memory.store(0x100, value.clone()).unwrap();

        let load_value = memory.load(0x100, 32).unwrap();

        assert_eq!(load_value, value);

        let load_0 = memory.load(0x100, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xDD, 8)));

        let load_0 = memory.load(0x101, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xCC, 8)));

        let load_0 = memory.load(0x102, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xBB, 8)));

        let load_0 = memory.load(0x103, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xAA, 8)));

        memory.store(0x102, KSet::constant(il::const_(0xFF, 8))).unwrap();

        let load_0 = memory.load(0x100, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xDD, 8)));

        let load_0 = memory.load(0x101, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xCC, 8)));

        let load_0 = memory.load(0x102, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xFF, 8)));

        let load_0 = memory.load(0x103, 8).unwrap();
        assert_eq!(load_0, KSet::constant(il::const_(0xAA, 8)));

        assert_eq!(memory.load(0x100, 32).unwrap(), KSet::constant(il::const_(0xAAFFCCDD, 32)));

        let other_memory: Memory<KSet> = Memory::new(Endian::Little);
        let memory = memory.join(&other_memory).unwrap();

        assert_eq!(memory.load(0x100, 32).unwrap(), KSet::constant(il::const_(0xAAFFCCDD, 32)));        
    }
}