Bug Summary

File:utils/utils.c
Warning:line 130, column 28
The result of the left shift is undefined because the left operand is negative

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name utils.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/var/lib/jenkins/workspace/scan-build-libcss -resource-dir /usr/lib/llvm-14/lib/clang/14.0.6 -D _BSD_SOURCE -D _DEFAULT_SOURCE -I /var/lib/jenkins/workspace/scan-build-libcss/include/ -I /var/lib/jenkins/workspace/scan-build-libcss/src -D _ALIGNED=__attribute__((aligned)) -D STMTEXPR=1 -D DEBUG -I /var/lib/jenkins/artifacts-x86_64-linux-gnu/include -internal-isystem /usr/lib/llvm-14/lib/clang/14.0.6/include -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -Og -Wwrite-strings -Wno-error -std=c99 -fconst-strings -fdebug-compilation-dir=/var/lib/jenkins/workspace/scan-build-libcss -ferror-limit 19 -fgnuc-version=4.2.1 -analyzer-display-progress -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /var/lib/jenkins/workspace/scan-build-libcss/clangScanBuildReports/2024-05-27-135458-3239081-1 -x c src/utils/utils.c
1/*
2 * This file is part of LibCSS.
3 * Licensed under the MIT License,
4 * http://www.opensource.org/licenses/mit-license.php
5 * Copyright 2007-9 John-Mark Bell <jmb@netsurf-browser.org>
6 */
7
8#include "utils/utils.h"
9
10css_fixed css__number_from_lwc_string(lwc_string *string,
11 bool_Bool int_only, size_t *consumed)
12{
13 if (string == NULL((void*)0) || lwc_string_length(string)({((string != ((void*)0)) ? (void) (0) : __assert_fail ("string != NULL"
, "src/utils/utils.c", 13, __extension__ __PRETTY_FUNCTION__)
); (string)->len;}) == 0 ||
1
Assuming 'string' is not equal to NULL
→
2
←
'?' condition is true
→
3
←
Assuming the condition is false
→
5
←
Taking false branch
→
14 consumed == NULL((void*)0))
4
←
Assuming 'consumed' is not equal to NULL
→
15 return 0;
16
17 return css__number_from_string(
8
←
Calling 'css__number_from_string'
→
18 (uint8_t *)lwc_string_data(string)({((string != ((void*)0)) ? (void) (0) : __assert_fail ("string != NULL"
, "src/utils/utils.c", 18, __extension__ __PRETTY_FUNCTION__)
); (const char *)((string)+1);}),
6
←
'?' condition is true
→
19 lwc_string_length(string)({((string != ((void*)0)) ? (void) (0) : __assert_fail ("string != NULL"
, "src/utils/utils.c", 19, __extension__ __PRETTY_FUNCTION__)
); (string)->len;}),
7
←
'?' condition is true
→
20 int_only,
21 consumed);
22}
23
24css_fixed css__number_from_string(const uint8_t *data, size_t len,
25 bool_Bool int_only, size_t *consumed)
26{
27 const uint8_t *ptr = data;
28 int sign = 1;
29 int32_t intpart = 0;
30 int32_t fracpart = 0;
31 int32_t pwr = 1;
32
33 if (data
8.1
'data' is not equal to NULL
 == NULL((void*)0) || len
8.2
'len' is not equal to 0
 == 0 || consumed
8.3
'consumed' is not equal to NULL
 == NULL((void*)0))
9
←
Taking false branch
→
34 return 0;
35
36 /* number = [+-]? ([0-9]+ | [0-9]* '.' [0-9]+) */
37
38 /* Extract sign, if any */
39 if (ptr[0] == '-') {
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
40 sign = -1;
41 len--;
42 ptr++;
43 } else if (ptr[0] == '+') {
12
←
Assuming the condition is false
→
13
←
Taking false branch
→
44 len--;
45 ptr++;
46 }
47
48 /* Ensure we have either a digit or a '.' followed by a digit */
49 if (len
13.1
'len' is not equal to 0
 == 0) {
14
←
Taking false branch
→
50 *consumed = 0;
51 return 0;
52 } else {
53 if (ptr[0] == '.') {
15
←
Assuming the condition is false
→
54 if (len == 1 || ptr[1] < '0' || '9' < ptr[1]) {
55 *consumed = 0;
56 return 0;
57 }
58 } else if (ptr[0] < '0' || '9' < ptr[0]) {
16
←
Assuming the condition is false
→
17
←
Assuming the condition is false
→
18
←
Taking false branch
→
59 *consumed = 0;
60 return 0;
61 }
62 }
63
64 /* Now extract intpart, assuming base 10 */
65 while (len
18.1
'len' is > 0
 > 0) {
21
←
Assuming 'len' is > 0
→
26
←
Assuming 'len' is > 0
→
32
←
Assuming 'len' is > 0
→
66 /* Stop on first non-digit */
67 if (ptr[0] < '0' || '9' < ptr[0])
19
←
Taking false branch
→
22
←
Assuming the condition is false
→
23
←
Assuming the condition is false
→
24
←
Taking false branch
→
27
←
Assuming the condition is false
→
28
←
Assuming the condition is false
→
29
←
Taking false branch
→
33
←
Assuming the condition is true
→
68 break;
69
70 /* Prevent overflow of 'intpart'; proper clamping below */
71 if (intpart < (1 << 22)) {
20
←
Taking true branch
→
25
←
Taking true branch
→
30
←
Assuming the condition is false
→
31
←
Taking false branch
→
72 intpart *= 10;
73 intpart += ptr[0] - '0';
74 }
75 ptr++;
76 len--;
77 }
78
79 /* And fracpart, again, assuming base 10 */
80 if (int_only == false0 && len > 1 && ptr[0] == '.' &&
34
←
Assuming 'int_only' is equal to false
→
35
←
Assuming 'len' is > 1
→
36
←
Assuming the condition is true
→
39
←
Taking true branch
→
81 ('0' <= ptr[1] && ptr[1] <= '9')) {
37
←
Assuming the condition is true
→
38
←
Assuming the condition is true
→
82 ptr++;
83 len--;
84
85 while (len
39.1
'len' is > 0
 > 0) {
42
←
Assuming 'len' is <= 0
→
43
←
Loop condition is false. Execution continues on line 97
→
86 if (ptr[0] < '0' || '9' < ptr[0])
40
←
Taking false branch
→
87 break;
88
89 if (pwr
40.1
'pwr' is < 1000000
 < 1000000) {
41
←
Taking true branch
→
90 pwr *= 10;
91 fracpart *= 10;
92 fracpart += ptr[0] - '0';
93 }
94 ptr++;
95 len--;
96 }
97 fracpart = ((1 << 10) * fracpart + pwr/2) / pwr;
98 if (fracpart >= (1 << 10)) {
44
←
Assuming the condition is true
→
45
←
Taking true branch
→
99 intpart++;
46
←
Value assigned to 'intpart'
→
100 fracpart &= (1 << 10) - 1;
101 }
102 }
103
104 *consumed = ptr - data;
105
106 if (sign
46.1
'sign' is > 0
 > 0) {
47
←
Taking true branch
→
107 /* If the result is larger than we can represent,
108 * then clamp to the maximum value we can store. */
109 if (intpart >= (1 << 21)) {
48
←
Assuming the condition is false
→
49
←
Taking false branch
→
110 intpart = (1 << 21) - 1;
111 fracpart = (1 << 10) - 1;
112 }
113 }
114 else {
115 /* If the negated result is smaller than we can represent
116 * then clamp to the minimum value we can store. */
117 if (intpart >= (1 << 21)) {
118 intpart = -(1 << 21);
119 fracpart = 0;
120 }
121 else {
122 intpart = -intpart;
123 if (fracpart) {
124 fracpart = (1 << 10) - fracpart;
125 intpart--;
126 }
127 }
128 }
129
130 return ((uint32_t)intpart << 10) | fracpart;
50
←
The result of the left shift is undefined because the left operand is negative
131}
132