hohn/codeql
1
0
Fork 0
mirror of https://github.com/github/codeql.git synced 2026-01-29 14:23:03 +01:00
Code Issues Packages Projects Releases Wiki Activity

Beautify .qhelp file

Browse Source
This commit is contained in:
Slavomir
2020-04-30 16:59:30 +03:00
parent 127cd3d003
commit 836b8965e2
1 changed files with 31 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

67
ql/src/experimental/CWE-681/IncorrectNumericConversion.qhelp
View File

@@ -1,78 +1,73 @@
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<overview>
<p>
If a numeric value string is parsed using <code>strconv.Atoi</code> into an int, and subsequently that int
is converted into another type of a lower bit size, the result can produce unexpected values.
If a numeric value string is parsed using <code>strconv.Atoi</code> into an int, and subsequently that int
is converted into another type of a lower bit size, the result can produce unexpected values.
</p>
<p>
This also applie to the results of <code>strconv.ParseFloat</code>, <code>strconv.ParseInt</code>,
and <code>strconv.ParseUint</code> when the specified bit size is higher than the bit size of the
type that number is converted to.
This also applie to the results of <code>strconv.ParseFloat</code>, <code>strconv.ParseInt</code>,
and <code>strconv.ParseUint</code> when the specified bit size is higher than the bit size of the
type that number is converted to.
</p>
</overview>
<recommendation>
<p>
If you need to parse numeric values with specific bit sizes, avoid <code>strconv.Atoi</code>, and, instead,
use the functions specific to each type (<code>strconv.ParseFloat</code>, <code>strconv.ParseInt</code>,
<code>strconv.ParseUint</code>) that also allow to specify the wanted bit size.
If you need to parse numeric values with specific bit sizes, avoid <code>strconv.Atoi</code>, and, instead,
use the functions specific to each type (<code>strconv.ParseFloat</code>, <code>strconv.ParseInt</code>,
<code>strconv.ParseUint</code>) that also allow to specify the wanted bit size.
</p>
<p>
When using those functions, be careful to not convert the result to another type with a lower bit size than
the bit size you specified when parsing the number.
When using those functions, be careful to not convert the result to another type with a lower bit size than
the bit size you specified when parsing the number.
</p>
<p>
If this is not possible, then add upper (and lower) bound checks specific to each type and
bit size (you can find the min and max value for each type in the `math` package).
If this is not possible, then add upper (and lower) bound checks specific to each type and
bit size (you can find the min and max value for each type in the `math` package).
</p>
</recommendation>
<example>
<p>
In the first example, assume that an input string is passed to <code>parseAllocateBad1</code> function,
parsed by <code>strconv.Atoi</code>, and then converted into an <code>int32</code> type:
In the first example, assume that an input string is passed to <code>parseAllocateBad1</code> function,
parsed by <code>strconv.Atoi</code>, and then converted into an <code>int32</code> type:
</p>
<sample src="IncorrectNumericConversion.go"/>
<p>
The bounds are not checked, so this means that if the provided number is greater than max int32,
the resulting value from the conversion will be different from the actual provided value.
The bounds are not checked, so this means that if the provided number is greater than max int32,
the resulting value from the conversion will be different from the actual provided value.
</p>
<p>
To avoid unexpected values, you should either use the other functions provided by the <code>strconv</code>
package to parse the specific types and bit sizes; in this case, <code>strconv.ParseInt</code> as you
can see in <code>parseAllocateGood2</code> function; or check bounds as in <code>parseAllocateGood1</code>
function.
To avoid unexpected values, you should either use the other functions provided by the <code>strconv</code>
package to parse the specific types and bit sizes; in this case, <code>strconv.ParseInt</code> as you
can see in <code>parseAllocateGood2</code> function; or check bounds as in <code>parseAllocateGood1</code>
function.
</p>
<sample src="IncorrectNumericConversionGood.go"/>
</example>
<example>
<p>
In the second example, assume that an input string is passed to <code>parseAllocateBad2</code> function,
parsed by <code>strconv.ParseInt</code> with a bit size set to 64, and then converted into an <code>int32</code> type:
In the second example, assume that an input string is passed to <code>parseAllocateBad2</code> function,
parsed by <code>strconv.ParseInt</code> with a bit size set to 64, and then converted into an <code>int32</code> type:
</p>
<sample src="IncorrectNumericConversion.go"/>
<p>
If the provided number is greater than max int32, the resulting value from the conversion will be
different from the actual provided value.
If the provided number is greater than max int32, the resulting value from the conversion will be
different from the actual provided value.
</p>
<p>
To avoid unexpected values, you should specify the correct bit size as in <code>parseAllocateGood3</code>;
or check bounds before making the conversion as in <code>parseAllocateGood4</code>.
To avoid unexpected values, you should specify the correct bit size as in <code>parseAllocateGood3</code>;
or check bounds before making the conversion as in <code>parseAllocateGood4</code>.
</p>
<sample src="IncorrectNumericConversionGood.go"/>
</example>
<references>
<li>
mitre.org: <a href="https://cwe.mitre.org/data/definitions/681.html">CWE-681: Incorrect Conversion between Numeric Types</a>.
mitre.org: <a href="https://cwe.mitre.org/data/definitions/681.html">CWE-681: Incorrect Conversion between Numeric Types</a>.
</li>
<li>
mitre.org: <a href="https://cwe.mitre.org/data/definitions/190.html">CWE-190: Integer Overflow or Wraparound</a>.
mitre.org: <a href="https://cwe.mitre.org/data/definitions/190.html">CWE-190: Integer Overflow or Wraparound</a>.
</li>
</references>
</qhelp>
</qhelp>