Make estimateCiphertextSize work with cached keys #30
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
estimateCiphertextSize was not passing a plaintext size down to the CMM, so the caching CMM assumed that a streaming encryption of unknown size was being performed, and bypassed the cache entirely. This change passes a plaintext size of zero instead to allow cached keys to be used; since we don't actually encrypt any data it's safe to not consume any of the byte limit. Note that this may not behave quite right if the CMM does more clever things with plaintext size. In general we should probably resolve this by moving estimateCiphertextSize over to the Cipher*Stream objects instead, where it can know the actual DataKeys in use instead of hoping they're reasonably consistently sized. Fixes: aws#29
Member
|
LGTM. I also checked the Python client to verify, and this issue is not present there due to the way that ciphertext size estimation is implemented. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
estimateCiphertextSize was not passing a plaintext size down to the CMM, so the
caching CMM assumed that a streaming encryption of unknown size was being
performed, and bypassed the cache entirely.
This change passes a plaintext size of zero instead to allow cached keys to be
used; since we don't actually encrypt any data it's safe to not consume any of
the byte limit.
Note that this may not behave quite right if the CMM does more clever things
with plaintext size. In general we should probably resolve this by moving
estimateCiphertextSize over to the Cipher*Stream objects instead, where it can
know the actual DataKeys in use instead of hoping they're reasonably
consistently sized.
Fixes: #29