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

1use std::collections::HashSet;
2
3use once_cell::sync::OnceCell;
4
5use rustc_middle::{mir::Local, ty::TyCtxt};
6use rustc_span::Span;
7
8use super::{report_encoding_bug, value_is_from_const};
9use crate::analysis::dataflow::*;
10use crate::check::opt::OptCheck;
11use crate::helpers::def_path::DefPath;
12
13static DEFPATHS: OnceCell<DefPaths> = OnceCell::new();
14
15struct DefPaths {
16    str_from_utf8: DefPath,
17}
18
19impl DefPaths {
20    pub fn new(tcx: &TyCtxt<'_>) -> Self {
21        Self {
22            str_from_utf8: DefPath::new("std::str::from_utf8", &tcx),
23        }
24    }
25}
26
27pub struct ArrayEncodingCheck {
28    record: Vec<Span>,
29}
30
31fn extract_ancestor_set_if_is_str_from(
32    graph: &Graph,
33    node_idx: Local,
34    node: &GraphNode,
35) -> Option<HashSet<Local>> {
36    let def_paths = DEFPATHS.get().unwrap();
37    for op in node.ops.iter() {
38        if let NodeOp::Call(def_id) = op {
39            if *def_id == def_paths.str_from_utf8.last_def_id() {
40                return Some(graph.collect_ancestor_locals(node_idx, false));
41            }
42        }
43    }
44    None
45}
46
47fn is_valid_index_edge(graph: &Graph, edge: &GraphEdge) -> bool {
48    if let EdgeOp::Index = edge.op {
49        // must be Index edge
50        let dst_node = &graph.nodes[edge.dst];
51        if dst_node.in_edges.len() > 2 {
52            // must be the left value
53            let rvalue_edge_idx = dst_node.in_edges[2];
54            let rvalue_idx = graph.edges[rvalue_edge_idx].src;
55            if value_is_from_const(graph, rvalue_idx) {
56                return true;
57            }
58        }
59    }
60    false
61}
62
63impl OptCheck for ArrayEncodingCheck {
64    fn new() -> Self {
65        Self { record: Vec::new() }
66    }
67
68    fn check(&mut self, graph: &Graph, tcx: &TyCtxt) {
69        let _ = &DEFPATHS.get_or_init(|| DefPaths::new(tcx));
70        let common_ancestor = graph
71            .edges
72            .iter()
73            .filter_map(|edge| {
74                // The index must be an lvalue and the rvalue must come from a const
75                if is_valid_index_edge(graph, edge) {
76                    Some(graph.collect_ancestor_locals(edge.src, true))
77                } else {
78                    None
79                }
80            })
81            .reduce(|set1, set2| set1.into_iter().filter(|k| set2.contains(k)).collect());
82
83        if let Some(common_ancestor) = common_ancestor {
84            for (node_idx, node) in graph.nodes.iter_enumerated() {
85                if let Some(str_from_ancestor_set) =
86                    extract_ancestor_set_if_is_str_from(graph, node_idx, node)
87                {
88                    if !common_ancestor
89                        .intersection(&str_from_ancestor_set)
90                        .next()
91                        .is_some()
92                    {
93                        self.record.clear();
94                        return;
95                    }
96                    self.record.push(node.span);
97                }
98            }
99        }
100    }
101
102    fn report(&self, graph: &Graph) {
103        for span in self.record.iter() {
104            report_encoding_bug(graph, *span);
105        }
106    }
107
108    fn cnt(&self) -> usize {
109        self.record.len()
110    }
111}
rapx/check/opt/checking/encoding_checking/array_encoding.rs

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