1 // SPDX-License-Identifier: GPL-2.0-only
2 ///
3 /// Use kfree_sensitive, kvfree_sensitive rather than memset or
4 /// memzero_explicit followed by kfree.
5 ///
6 // Confidence: High
7 // Copyright: (C) 2020 Denis Efremov ISPRAS
8 // Options: --no-includes --include-headers
9 //
10 // Keywords: kfree_sensitive, kvfree_sensitive
11 //
12
13 virtual context
14 virtual patch
15 virtual org
16 virtual report
17
18 @initialize:python@
19 @@
20 # kmalloc_oob_in_memset uses memset to explicitly trigger out-of-bounds access
21 filter = frozenset(['kmalloc_oob_in_memset',
22 'kfree_sensitive', 'kvfree_sensitive'])
23
24 def relevant(p):
25 return not (filter & {el.current_element for el in p})
26
27 @cond@
28 position ok;
29 @@
30
31 if (...)
32 \(memset@ok\|memzero_explicit@ok\)(...);
33
34 @r depends on !patch forall@
35 expression E;
36 position p : script:python() { relevant(p) };
37 position m != cond.ok;
38 type T;
39 @@
40
41 (
42 * memset@m((T)E, 0, ...);
43 |
44 * memzero_explicit@m((T)E, ...);
45 )
46 ... when != E
47 when strict
48 * \(kfree\|vfree\|kvfree\)(E)@p;
49
50 @rp_memzero depends on patch@
51 expression E, size;
52 position p : script:python() { relevant(p) };
53 position m != cond.ok;
54 type T;
55 @@
56
57 - memzero_explicit@m((T)E, size);
58 ... when != E
59 when strict
60 (
61 - kfree(E)@p;
62 + kfree_sensitive(E);
63 |
64 - \(vfree\|kvfree\)(E)@p;
65 + kvfree_sensitive(E, size);
66 )
67
68 @rp_memset depends on patch@
69 expression E, size;
70 position p : script:python() { relevant(p) };
71 position m != cond.ok;
72 type T;
73 @@
74
75 - memset@m((T)E, 0, size);
76 ... when != E
77 when strict
78 (
79 - kfree(E)@p;
80 + kfree_sensitive(E);
81 |
82 - \(vfree\|kvfree\)(E)@p;
83 + kvfree_sensitive(E, size);
84 )
85
86 @script:python depends on report@
87 p << r.p;
88 m << r.m;
89 @@
90
91 msg = "WARNING opportunity for kfree_sensitive/kvfree_sensitive (memset at line %s)"
92 coccilib.report.print_report(p[0], msg % (m[0].line))
93
94 @script:python depends on org@
95 p << r.p;
96 m << r.m;
97 @@
98
99 msg = "WARNING opportunity for kfree_sensitive/kvfree_sensitive (memset at line %s)"
100 coccilib.org.print_todo(p[0], msg % (m[0].line))
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