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Noncompliant Code Example (Bit-Field Overlap)
In the following this noncompliant code example, assuming 8 bits to a byte, if bit-fields of 6 and 4 bits are declared, is each bit-field contained within a byte, or are the bit-fields split across multiple bytes?
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Making invalid assumptions about the type of type-cast data, especially bit-fields, can result in unexpected data values.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
EXP11-C |
Medium |
Probable |
Medium | P8 | L2 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| Supported: Astrée reports runtime errors resulting from invalid assumptions. | |||||||
| Compass/ROSE |
Can detect violations of this recommendation. Specifically, it reports violations if
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| Helix QAC |
|
|
|
94 S
95 S
Fully implemented
| C0310, C0751 | ||
| LDRA tool suite |
|
|
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554 S |
Fully implemented |
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this recommendation on the CERT website.
Related Guidelines
| SEI CERT C++ |
| Coding Standard | VOID EXP11-CPP. Do not apply operators expecting one type to data of an incompatible type |
| ISO/IEC TR 24772:2013 | Bit Representations [STR] |
| MISRA C:2012 | Directive 1.1 (required) |
Bibliography
| [Plum 1985] | Rule 6-5: In portable code, do not depend upon the allocation order of bit-fields within a word |
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