Fix incorrect address check in CalculateChecksum (close #6)

[bessman]

Summary by Sourcery

Bug Fixes:

• Correct the address range check in the CalculateChecksum function to prevent potential memory errors.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request fixes an incorrect address range check in the CalculateChecksum function. The issue was caused by using the full data length instead of half the data length when calculating the end address of the range. This change ensures that only the necessary memory range is checked, preventing potential issues.

State diagram for address range validation

stateDiagram-v2
    [*] --> CheckRange
    CheckRange --> ValidRange: address + dataLength/2
    CheckRange --> InvalidRange: address + dataLength/2
    ValidRange --> ProcessChecksum
    InvalidRange --> ErrorHandling
    ProcessChecksum --> [*]
    ErrorHandling --> [*]
    note right of CheckRange
        Fixed calculation using
        dataLength/2 instead of
        dataLength-1
    end note

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File-Level Changes

Change	Details	Files
Fixed incorrect address range check	Changed the end address calculation in the IsLegalRange check to use half the data length. This corrects the range used for the checksum calculation, ensuring that it covers the correct memory area. Updated the condition in the IsLegalRange check from pCommand->address+pCommand->dataLength-1 to pCommand->address+pCommand->dataLength / 2 to reflect the corrected range. This prevents potential access violations or incorrect checksum calculations.	src/mcc_generated_files/boot/boot_process.c

Possibly linked issues

• CalculateChecksum fails for addresses close to the upper end of the program memory range #6: The PR fixes the address validity check in CalculateChecksum, addressing the issue.

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[sourcery-ai]

Hey @bessman - I've reviewed your changes and found some issues that need to be addressed.

Blocking issues:

• The range check validates only half the actual memory access range, risking buffer overruns (link)

Overall Comments:

• Please add a comment explaining why the address range needs to be divided by 2 (e.g., if this is converting between byte and word addresses)

Here's what I looked at during the review

• 🔴 General issues: 1 blocking issue
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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