1/// Unsigned expressions cannot be lesser than zero. Presence of
 2/// comparisons 'unsigned (<|<=|>|>=) 0' often indicates a bug,
 3/// usually wrong type of variable.
 4///
 5/// To reduce number of false positives following tests have been added:
 6/// - parts of range checks are skipped, eg. "if (u < 0 || u > 15) ...",
 7///   developers prefer to keep such code,
 8/// - comparisons "<= 0" and "> 0" are performed only on results of
 9///   signed functions/macros,
10/// - hardcoded list of signed functions/macros with always non-negative
11///   result is used to avoid false positives difficult to detect by other ways
12///
13// Confidence: Average
14// Copyright: (C) 2015 Andrzej Hajda, Samsung Electronics Co., Ltd. GPLv2.
15// URL: http://coccinelle.lip6.fr/
16// Options: --all-includes
17
18virtual context
19virtual org
20virtual report
21
22@r_cmp@
23position p;
24typedef bool, u8, u16, u32, u64;
25{unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long,
26	size_t, bool, u8, u16, u32, u64} v;
27expression e;
28@@
29
30	\( v = e \| &v \)
31	...
32	(\( v@p < 0 \| v@p <= 0 \| v@p >= 0 \| v@p > 0 \))
33
34@r@
35position r_cmp.p;
36typedef s8, s16, s32, s64;
37{char, short, int, long, long long, ssize_t, s8, s16, s32, s64} vs;
38expression c, e, v;
39identifier f !~ "^(ata_id_queue_depth|btrfs_copy_from_user|dma_map_sg|dma_map_sg_attrs|fls|fls64|gameport_time|get_write_extents|nla_len|ntoh24|of_flat_dt_match|of_get_child_count|uart_circ_chars_pending|[A-Z0-9_]+)$";
40@@
41
42(
43	v = f(...)@vs;
44	... when != v = e;
45*	(\( v@p <=@e 0 \| v@p >@e 0 \))
46	... when any
47|
48(
49	(\( v@p < 0 \| v@p <= 0 \)) || ... || (\( v >= c \| v > c \))
50|
51	(\( v >= c \| v > c \)) || ... || (\( v@p < 0 \| v@p <= 0 \))
52|
53	(\( v@p >= 0 \| v@p > 0 \)) && ... && (\( v < c \| v <= c \))
54|
55	((\( v < c \| v <= c \) && ... && \( v@p >= 0 \| v@p > 0 \)))
56|
57*	(\( v@p <@e 0 \| v@p >=@e 0 \))
58)
59)
60
61@script:python depends on org@
62p << r_cmp.p;
63e << r.e;
64@@
65
66msg = "WARNING: Unsigned expression compared with zero: %s" % (e)
67coccilib.org.print_todo(p[0], msg)
68
69@script:python depends on report@
70p << r_cmp.p;
71e << r.e;
72@@
73
74msg = "WARNING: Unsigned expression compared with zero: %s" % (e)
75coccilib.report.print_report(p[0], msg)

 1// SPDX-License-Identifier: GPL-2.0-only
 2/// Unsigned expressions cannot be lesser than zero. Presence of
 3/// comparisons 'unsigned (<|<=|>|>=) 0' often indicates a bug,
 4/// usually wrong type of variable.
 5///
 6/// To reduce number of false positives following tests have been added:
 7/// - parts of range checks are skipped, eg. "if (u < 0 || u > 15) ...",
 8///   developers prefer to keep such code,
 9/// - comparisons "<= 0" and "> 0" are performed only on results of
10///   signed functions/macros,
11/// - hardcoded list of signed functions/macros with always non-negative
12///   result is used to avoid false positives difficult to detect by other ways
13///
14// Confidence: Average
15// Copyright: (C) 2015 Andrzej Hajda, Samsung Electronics Co., Ltd.
16// URL: http://coccinelle.lip6.fr/
17// Options: --all-includes
18
19virtual context
20virtual org
21virtual report
22
23@r_cmp@
24position p;
25typedef bool, u8, u16, u32, u64;
26{unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long,
27	size_t, bool, u8, u16, u32, u64} v;
28expression e;
29@@
30
31	\( v = e \| &v \)
32	...
33	(\( v@p < 0 \| v@p <= 0 \| v@p >= 0 \| v@p > 0 \))
34
35@r@
36position r_cmp.p;
37typedef s8, s16, s32, s64;
38{char, short, int, long, long long, ssize_t, s8, s16, s32, s64} vs;
39expression c, e, v;
40identifier f !~ "^(ata_id_queue_depth|btrfs_copy_from_user|dma_map_sg|dma_map_sg_attrs|fls|fls64|gameport_time|get_write_extents|nla_len|ntoh24|of_flat_dt_match|of_get_child_count|uart_circ_chars_pending|[A-Z0-9_]+)$";
41@@
42
43(
44	v = f(...)@vs;
45	... when != v = e;
46*	(\( v@p <=@e 0 \| v@p >@e 0 \))
47	... when any
48|
49(
50	(\( v@p < 0 \| v@p <= 0 \)) || ... || (\( v >= c \| v > c \))
51|
52	(\( v >= c \| v > c \)) || ... || (\( v@p < 0 \| v@p <= 0 \))
53|
54	(\( v@p >= 0 \| v@p > 0 \)) && ... && (\( v < c \| v <= c \))
55|
56	((\( v < c \| v <= c \) && ... && \( v@p >= 0 \| v@p > 0 \)))
57|
58*	(\( v@p <@e 0 \| v@p >=@e 0 \))
59)
60)
61
62@script:python depends on org@
63p << r_cmp.p;
64e << r.e;
65@@
66
67msg = "WARNING: Unsigned expression compared with zero: %s" % (e)
68coccilib.org.print_todo(p[0], msg)
69
70@script:python depends on report@
71p << r_cmp.p;
72e << r.e;
73@@
74
75msg = "WARNING: Unsigned expression compared with zero: %s" % (e)
76coccilib.report.print_report(p[0], msg)