xref: /linux/scripts/coccinelle/null/deref_null.cocci (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9) 
1///
2/// A variable is dereferenced under a NULL test.
3/// Even though it is known to be NULL.
4///
5// Confidence: Moderate
6// Copyright: (C) 2010 Nicolas Palix, DIKU.  GPLv2.
7// Copyright: (C) 2010 Julia Lawall, DIKU.  GPLv2.
8// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6.  GPLv2.
9// URL: http://coccinelle.lip6.fr/
10// Comments: -I ... -all_includes can give more complete results
11// Options:
12
13virtual context
14virtual org
15virtual report
16
17@ifm@
18expression *E;
19statement S1,S2;
20position p1;
21@@
22
23if@p1 ((E == NULL && ...) || ...) S1 else S2
24
25// The following two rules are separate, because both can match a single
26// expression in different ways
27@pr1 expression@
28expression *ifm.E;
29identifier f;
30position p1;
31@@
32
33 (E != NULL && ...) ? <+...E->f@p1...+> : ...
34
35@pr2 expression@
36expression *ifm.E;
37identifier f;
38position p2;
39@@
40
41(
42  (E != NULL) && ... && <+...E->f@p2...+>
43|
44  (E == NULL) || ... || <+...E->f@p2...+>
45|
46 sizeof(<+...E->f@p2...+>)
47)
48
49// For org and report modes
50
51@r depends on !context && (org || report) exists@
52expression subE <= ifm.E;
53expression *ifm.E;
54expression E1,E2;
55identifier f;
56statement S1,S2,S3,S4;
57iterator iter;
58position p!={pr1.p1,pr2.p2};
59position ifm.p1;
60@@
61
62if@p1 ((E == NULL && ...) || ...)
63{
64  ... when != if (...) S1 else S2
65(
66 iter(subE,...) S4 // no use
67|
68 list_remove_head(E2,subE,...)
69|
70 subE = E1
71|
72 for(subE = E1;...;...) S4
73|
74 subE++
75|
76 ++subE
77|
78 --subE
79|
80 subE--
81|
82 &subE
83|
84 E->f@p // bad use
85)
86  ... when any
87  return ...;
88}
89else S3
90
91@script:python depends on !context && !org && report@
92p << r.p;
93p1 << ifm.p1;
94x << ifm.E;
95@@
96
97msg="ERROR: %s is NULL but dereferenced." % (x)
98coccilib.report.print_report(p[0], msg)
99cocci.include_match(False)
100
101@script:python depends on !context && org && !report@
102p << r.p;
103p1 << ifm.p1;
104x << ifm.E;
105@@
106
107msg="ERROR: %s is NULL but dereferenced." % (x)
108msg_safe=msg.replace("[","@(").replace("]",")")
109cocci.print_main(msg_safe,p)
110cocci.include_match(False)
111
112@s depends on !context && (org || report) exists@
113expression subE <= ifm.E;
114expression *ifm.E;
115expression E1,E2;
116identifier f;
117statement S1,S2,S3,S4;
118iterator iter;
119position p!={pr1.p1,pr2.p2};
120position ifm.p1;
121@@
122
123if@p1 ((E == NULL && ...) || ...)
124{
125  ... when != if (...) S1 else S2
126(
127 iter(subE,...) S4 // no use
128|
129 list_remove_head(E2,subE,...)
130|
131 subE = E1
132|
133 for(subE = E1;...;...) S4
134|
135 subE++
136|
137 ++subE
138|
139 --subE
140|
141 subE--
142|
143 &subE
144|
145 E->f@p // bad use
146)
147  ... when any
148}
149else S3
150
151@script:python depends on !context && !org && report@
152p << s.p;
153p1 << ifm.p1;
154x << ifm.E;
155@@
156
157msg="ERROR: %s is NULL but dereferenced." % (x)
158coccilib.report.print_report(p[0], msg)
159
160@script:python depends on !context && org && !report@
161p << s.p;
162p1 << ifm.p1;
163x << ifm.E;
164@@
165
166msg="ERROR: %s is NULL but dereferenced." % (x)
167msg_safe=msg.replace("[","@(").replace("]",")")
168cocci.print_main(msg_safe,p)
169
170// For context mode
171
172@depends on context && !org && !report exists@
173expression subE <= ifm.E;
174expression *ifm.E;
175expression E1,E2;
176identifier f;
177statement S1,S2,S3,S4;
178iterator iter;
179position p!={pr1.p1,pr2.p2};
180position ifm.p1;
181@@
182
183if@p1 ((E == NULL && ...) || ...)
184{
185  ... when != if (...) S1 else S2
186(
187 iter(subE,...) S4 // no use
188|
189 list_remove_head(E2,subE,...)
190|
191 subE = E1
192|
193 for(subE = E1;...;...) S4
194|
195 subE++
196|
197 ++subE
198|
199 --subE
200|
201 subE--
202|
203 &subE
204|
205* E->f@p // bad use
206)
207  ... when any
208  return ...;
209}
210else S3
211
212// The following three rules are duplicates of ifm, pr1 and pr2 respectively.
213// It is need because the previous rule as already made a "change".
214
215@ifm1@
216expression *E;
217statement S1,S2;
218position p1;
219@@
220
221if@p1 ((E == NULL && ...) || ...) S1 else S2
222
223@pr11 expression@
224expression *ifm1.E;
225identifier f;
226position p1;
227@@
228
229 (E != NULL && ...) ? <+...E->f@p1...+> : ...
230
231@pr12 expression@
232expression *ifm1.E;
233identifier f;
234position p2;
235@@
236
237(
238  (E != NULL) && ... && <+...E->f@p2...+>
239|
240  (E == NULL) || ... || <+...E->f@p2...+>
241|
242 sizeof(<+...E->f@p2...+>)
243)
244
245@depends on context && !org && !report exists@
246expression subE <= ifm1.E;
247expression *ifm1.E;
248expression E1,E2;
249identifier f;
250statement S1,S2,S3,S4;
251iterator iter;
252position p!={pr11.p1,pr12.p2};
253position ifm1.p1;
254@@
255
256if@p1 ((E == NULL && ...) || ...)
257{
258  ... when != if (...) S1 else S2
259(
260 iter(subE,...) S4 // no use
261|
262 list_remove_head(E2,subE,...)
263|
264 subE = E1
265|
266 for(subE = E1;...;...) S4
267|
268 subE++
269|
270 ++subE
271|
272 --subE
273|
274 subE--
275|
276 &subE
277|
278* E->f@p // bad use
279)
280  ... when any
281}
282else S3
283