Skip to content
Snippets Groups Projects
Commit de6448ab authored by POTHURI HARIKA's avatar POTHURI HARIKA
Browse files

Upload New File

parent 1e025d0a
No related branches found
No related tags found
No related merge requests found
Show whitespace changes
Inline Side-by-side
Tools/SmartCheck/Solidity/Rules/SOLIDITY_UINT_CANT_BE_NEGATIVE.md 0 → 100644
+ 278
− 0
View file @ de6448ab
# Analysis of Smart Contract Security Vulnerabilities and Tools ![](https://img.shields.io/badge/-Live-brightgreen)
![](https://img.shields.io/badge/Batch-UG21CYS-lightgreen) ![](https://img.shields.io/badge/Batch-PG21CYS-green) ![](https://img.shields.io/badge/Batch-UG22CYS-lightgreen) ![](https://img.shields.io/badge/Batch-PG21CYS-green) ![](https://img.shields.io/badge/Batch-PhD-darkgreen) ![](https://img.shields.io/badge/-B_RIG-darkgreen)<br/> ![](https://img.shields.io/badge/BlockchainCourse-21CY712-green) ![](https://img.shields.io/badge/-M.Tech_Dissertation-blue) ![](https://img.shields.io/badge/Focus-Smart_Contract_Security-yellow) <br/>
![](https://img.shields.io/badge/Blockchain-Ethereum-blue) <br/>
![](https://img.shields.io/badge/Language-Solidity-blue)
## SOLIDITY_UINT_CANT_BE_NEGATIVE
### Rule Description
<p>
Variables of <code>uint</code> type cannot be negative. Thus, comparing <code>uint</code> variable with zero (greater than or equal) is redundant. Also, it may lead to an underflow issue. Moreover, comparison with zero used in <code>for</code>-loop condition results in an infinite loop.
</p>
### Solidity-Rules
![](https://img.shields.io/badge/Pattern_ID-11ca45b-gold) ![](https://img.shields.io/badge/Severity-3-brown)
```
(forStatement | whileStatement | doWhileStatement)
/condition/expression
[text()[1] = ">="]
[expression[2]/primaryExpression//decimalNumber[text()[1] = "0"]]
[expression[1]/primaryExpression/identifier
[text()[1]
= ancestor::functionDefinition//variableDeclaration
[typeName/elementaryTypeName[matches(text()[1], "uint")]]
/identifier/text()[1]
]
]
```
![](https://img.shields.io/badge/Pattern_ID-d48ac4-gold) ![](https://img.shields.io/badge/Severity-2-brown)
```
expression
[text()[1] = ">="]
[expression[2]/primaryExpression//decimalNumber[text()[1] = "0"]]
[expression[1]/(primaryExpression/identifier | identifier)
[
text()[1]
= ancestor::functionDefinition//variableDeclaration
[typeName/elementaryTypeName[matches(text()[1], "uint")]]
/identifier/text()[1]
or text()[1]
= ancestor::contractDefinition//(structDefinition/variableDeclaration | stateVariableDeclaration)
[typeName/elementaryTypeName[matches(text()[1], "uint")]]
/identifier/text()[1]
]
]
```
![](https://img.shields.io/badge/Pattern_ID-733fdd-gold) ![](https://img.shields.io/badge/Severity-2-brown)
```
expression
[text()[1]=">="]
[expression[2]//decimalNumber[text()[1] = "0"]]
[expression[1]/expression[1]//identifier
[text()[1]
= ancestor::contractDefinition//stateVariableDeclaration
[typeName/mappingSt/typeName[2]/elementaryTypeName[matches(text()[1],"uint")]]
/identifier/text()[1]
]
]
```
### Sample Code
```
pragma solidity 0.4.24;
contract UnderFlow {
uint8 a;
function foo_1() {
uint b;
int c = 1;
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE 11ca45b <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
for (uint i=100; i >= 0; i--) {
}
for (uint j=0; j <= 0; j--) {
}
for (uint k=100; k >= 1; k--) {
}
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
require(a >= 0);
require(a <= 0);
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
require(b >= 0);
require(b >= 7);
require(c >= 0);
}
struct Mystruct {
uint a1;
int a2;
}
function foo_2(Mystruct str) internal {
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
require(str.a1 >= 0);
require(str.a2 >= 0);
}
mapping(address => uint) balances;
mapping(address => int) ibalances;
function foo_3(address user) {
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE 733fdd
require(balances[user] >= 0);
require(ibalances[user] >= 0);
}
function foo_4() {
uint i;
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE 11ca45b <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
while(i >= 0) {
i--;
}
do {
i--;
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE 11ca45b <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
} while(i >=0);
for (uint i=100; i <= 0; i++) {
// <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE 11ca45b <yes> <report> SOLIDITY_UINT_CANT_BE_NEGATIVE d48ac4
for (uint i=100; i >= 0; i--) {
}
}
}
}
```
### Abstract Syntax Tree
[Click Here](https://astexplorer.net/#/gist/bed99fa12eeb0c46e69eb941be0da4a4/c851886b7a266f353f70ffb957720bb69864cfd5) to view the AST for the above code. Code generated from AST Explorer using _solidity-parser-antlr-0.4.11_
### Code Result
```
SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: 11ca45b
severity: 3
line: 10
column: 25
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: 11ca45b
severity: 3
line: 48
column: 14
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: 11ca45b
severity: 3
line: 54
column: 16
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: 11ca45b
severity: 3
line: 58
column: 29
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 10
column: 25
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 17
column: 16
content: a>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 20
column: 16
content: b>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 32
column: 16
content: str.a1>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 48
column: 14
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 54
column: 16
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: d48ac4
severity: 2
line: 58
column: 29
content: i>=0
ruleId: SOLIDITY_UINT_CANT_BE_NEGATIVE
patternId: 733fdd
severity: 2
line: 41
column: 16
content: balances[user]>=0
ruleId: SOLIDITY_UPGRADE_TO_050
patternId: 341gim
severity: 1
line: 30
column: 19
content: Mystructstr
ruleId: SOLIDITY_VISIBILITY
patternId: 910067
severity: 1
line: 6
column: 4
content: functionfoo_1(){uintb;intc=1;for(uinti=100;i>=0;i--){}for(uintj=0;j<=0;j--){}for(uintk=100;k>=1;k--){}require(a>=0);require(a<=0);require(b>=0);require(b>=7);require(c>=0);}
ruleId: SOLIDITY_VISIBILITY
patternId: 910067
severity: 1
line: 39
column: 4
content: functionfoo_3(addressuser){require(balances[user]>=0);require(ibalances[user]>=0);}
ruleId: SOLIDITY_VISIBILITY
patternId: 910067
severity: 1
line: 45
column: 4
content: functionfoo_4(){uinti;while(i>=0){i--;}do{i--;}while(i>=0);for(uinti=100;i<=0;i++){for(uinti=100;i>=0;i--){}}}
ruleId: SOLIDITY_VISIBILITY
patternId: b51ce0
severity: 1
line: 4
column: 4
content: uint8a;
ruleId: SOLIDITY_VISIBILITY
patternId: b51ce0
severity: 1
line: 36
column: 4
content: mapping(address=>uint)balances;
ruleId: SOLIDITY_VISIBILITY
patternId: b51ce0
severity: 1
line: 37
column: 4
content: mapping(address=>int)ibalances;
SOLIDITY_VISIBILITY :6
SOLIDITY_UPGRADE_TO_050 :1
SOLIDITY_UINT_CANT_BE_NEGATIVE :12
```
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Please register or to comment