Manifest header wrong comparation between two unsigned values #10
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This is a vulnerability in the manifest_flash.c header parse calculations. Corrupted manifest header results in DOS or much severe implications that might result with a possible RCE. E.g. Manifest header with length=0 cause the code to read the whole flash until crash. After updating a manifest with such malformed header, the system could be bricked. Thus fix the comparation between two unsigned values for detecting a negative value.
chweimer
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Dec 14, 2021
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chweimer
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chweimer
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There are a few comments on this change:
- When adding/changing code, please be sure to maintain formatting consistency with the existing code. In this particular case, there should be a space following the cast.
- It seems like it would be a better solution here to add an explicit check for the header->length field to ensure it is at least sizeof (struct manifest_header) bytes. If that check is added, there is no problem with the sig_length check as it is currently.
- Code in this repo follows TDD, so this change needs an associated unit test (maybe multiple) in manifest_flash_test exposing this problem, and proving the fix is good.
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This is a vulnerability in the manifest_flash.c header parse calculations.
Corrupted manifest header results in DOS or much severe implications that might end with a possible RCE.
E.g. Manifest header with length=0 cause the code to read the whole flash until crash. After updating a manifest with such malformed header, the system could be bricked.
Thus fix the comparation between two unsigned values for detecting a negative value.