rapx/check/opt/checking/encoding_checking/
vec_encoding.rs

1use std::collections::HashSet;
2
3use crate::analysis::dataflow::*;
4use crate::helpers::def_path::DefPath;
5use once_cell::sync::OnceCell;
6use rustc_middle::{mir::Local, ty::TyCtxt};
7use rustc_span::Span;
8
9use super::{report_encoding_bug, value_is_from_const};
10
11static DEFPATHS: OnceCell<DefPaths> = OnceCell::new();
12
13struct DefPaths {
14    string_from_utf8: DefPath,
15    string_from_utf8_lossy: DefPath,
16    vec_new: DefPath,
17    vec_with_capacity: DefPath,
18    vec_push: DefPath,
19}
20
21impl DefPaths {
22    // only supports push operation (can't support direct assignment)
23    pub fn new(tcx: &TyCtxt<'_>) -> Self {
24        Self {
25            string_from_utf8: DefPath::new("std::string::String::from_utf8", tcx),
26            string_from_utf8_lossy: DefPath::new("std::string::String::from_utf8_lossy", tcx),
27            vec_new: DefPath::new("std::vec::Vec::new", tcx),
28            vec_with_capacity: DefPath::new("std::vec::Vec::with_capacity", tcx),
29            vec_push: DefPath::new("std::vec::Vec::push", tcx),
30        }
31    }
32}
33
34use crate::check::opt::OptCheck;
35
36pub struct VecEncodingCheck {
37    record: Vec<Span>,
38}
39
40fn extract_vec_if_is_string_from(graph: &Graph, node: &GraphNode) -> Option<Local> {
41    let def_paths = &DEFPATHS.get().unwrap();
42    for op in node.ops.iter() {
43        if let NodeOp::Call(def_id) = op {
44            if *def_id == def_paths.string_from_utf8.last_def_id()
45                || *def_id == def_paths.string_from_utf8_lossy.last_def_id()
46            {
47                let in_edge = &graph.edges[node.in_edges[0]];
48                return Some(in_edge.src);
49            }
50        }
51    }
52    None
53}
54
55fn find_upside_vec_new_node(graph: &Graph, node_idx: Local) -> Option<Local> {
56    let mut vec_new_node_idx = None;
57    let def_paths = &DEFPATHS.get().unwrap();
58    // Warning: may traverse all upside nodes and the new result will overwrite on the previous result
59    let mut node_operator = |graph: &Graph, idx: Local| -> DFSStatus {
60        let node = &graph.nodes[idx];
61        for op in node.ops.iter() {
62            if let NodeOp::Call(def_id) = op {
63                if *def_id == def_paths.vec_new.last_def_id()
64                    || *def_id == def_paths.vec_with_capacity.last_def_id()
65                {
66                    vec_new_node_idx = Some(idx);
67                    return DFSStatus::Stop;
68                }
69            }
70        }
71        DFSStatus::Continue
72    };
73    let mut seen = HashSet::new();
74    graph.dfs(
75        node_idx,
76        Direction::Upside,
77        &mut node_operator,
78        &mut Graph::always_true_edge_validator,
79        false,
80        &mut seen,
81    );
82    vec_new_node_idx
83}
84
85// todo: we can find downside index node too
86
87fn find_downside_push_node(graph: &Graph, node_idx: Local) -> Vec<Local> {
88    let mut push_node_idxs: Vec<Local> = Vec::new();
89    let def_paths = &DEFPATHS.get().unwrap();
90    // Warning: traverse all downside nodes
91    let mut node_operator = |graph: &Graph, idx: Local| -> DFSStatus {
92        let node = &graph.nodes[idx];
93        for op in node.ops.iter() {
94            if let NodeOp::Call(def_id) = op {
95                if *def_id == def_paths.vec_push.last_def_id() {
96                    push_node_idxs.push(idx);
97                    break;
98                }
99            }
100        }
101        DFSStatus::Continue
102    };
103    let mut seen = HashSet::new();
104    graph.dfs(
105        node_idx,
106        Direction::Downside,
107        &mut node_operator,
108        &mut Graph::always_true_edge_validator,
109        true,
110        &mut seen,
111    );
112    push_node_idxs
113}
114
115impl OptCheck for VecEncodingCheck {
116    fn new() -> Self {
117        Self { record: Vec::new() }
118    }
119
120    fn check(&mut self, graph: &Graph, tcx: &TyCtxt) {
121        let _ = &DEFPATHS.get_or_init(|| DefPaths::new(tcx));
122        for node in graph.nodes.iter() {
123            if let Some(vec_node_idx) = extract_vec_if_is_string_from(graph, node) {
124                if let Some(vec_new_idx) = find_upside_vec_new_node(graph, vec_node_idx) {
125                    let vec_push_indice = find_downside_push_node(graph, vec_new_idx);
126                    for vec_push_idx in vec_push_indice {
127                        let pushed_value_edge = &graph.edges[graph.nodes[vec_push_idx].in_edges[1]]; // The second parameter
128                        let pushed_value_idx = pushed_value_edge.src;
129                        if !value_is_from_const(graph, pushed_value_idx) {
130                            self.record.clear();
131                            return;
132                        }
133                    }
134                    self.record.push(node.span);
135                }
136            }
137        }
138    }
139
140    fn report(&self, graph: &Graph) {
141        for span in self.record.iter() {
142            report_encoding_bug(graph, *span);
143        }
144    }
145
146    fn cnt(&self) -> usize {
147        self.record.len()
148    }
149}
rapx/check/opt/checking/encoding_checking/vec_encoding.rs

rapx/check/opt/checking/encoding_checking/
vec_encoding.rs
