No memory allocation for each C_DecryptUpdate.

[larssilven]

Before this change the allocated memory was growing after each
C_DecryptUpdate.
If a large amount of data is decrypted then the memory runs out ...

Summary by CodeRabbit

• Bug Fixes
  • Improved decryption handling to ensure encrypted data is only buffered in GCM mode, enhancing reliability for users in certain encryption scenarios.

[larssilven]

The 'currentAEADBuffer' that is growing for each update is just used for the GCM decryption. So my easy fix is just to not update this buffer when another cipher mode but GCM is used.
This is of course not fixing the problem for the GCM that also has to be fixed.
Maybe it would be better if each cipher mode should have its own class instead of using this 'mode' variable.

[coderabbitai]

Walkthrough

The change updates the decryptUpdate method in the SymmetricAlgorithm class so that encryptedData is appended to currentAEADBuffer only when the cipher mode is GCM, rather than unconditionally as before. The logic for updating currentBufferSize remains unchanged.

Changes

File(s)	Change Summary
src/lib/crypto/SymmetricAlgorithm.cpp	Modified decryptUpdate to append data to currentAEADBuffer only in GCM mode

Estimated code review effort

1 (~2 minutes)

Poem

A cipher's choice, so sly and neat,
Now buffers only when GCM’s the beat.
No more appending just because—
Only when the mode says "it must!"
With careful paws, this code I tend,
Security and order, rabbitly defend!
🐇✨

---

📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 557b2fd and ffbfd4f.

📒 Files selected for processing (1)

• src/lib/crypto/SymmetricAlgorithm.cpp (1 hunks)

🔇 Additional comments (1)

src/lib/crypto/SymmetricAlgorithm.cpp (1)

124-126: LGTM! Targeted fix addresses the memory allocation issue.

This conditional check correctly prevents unnecessary memory accumulation in currentAEADBuffer for non-GCM cipher modes. Since GCM is an AEAD mode that requires buffering the entire ciphertext for authentication verification, while other modes (CBC, ECB, CFB, CTR, OFB) do not, this logic is sound.

The change directly addresses the memory exhaustion problem described in the PR objectives for non-GCM modes, which is a significant improvement for large data decryption operations.

Note: As mentioned in the PR discussion, this is a practical quick fix that doesn't fully resolve the GCM mode memory issue, and the suggested architectural improvement of separate cipher mode classes remains a valid consideration for future refactoring.

✨ Finishing Touches

• 📝 Generate Docstrings

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

🪧 Tips

Chat

There are 3 ways to chat with CodeRabbit:

• Review comments: Directly reply to a review comment made by CodeRabbit. Example:
  • I pushed a fix in commit <commit_id>, please review it.
  • Explain this complex logic.
  • Open a follow-up GitHub issue for this discussion.
• Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query. Examples:
  • @coderabbitai explain this code block.
  • @coderabbitai modularize this function.
• PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
  • @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
  • @coderabbitai read src/utils.ts and explain its main purpose.
  • @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.
  • @coderabbitai help me debug CodeRabbit configuration file.

Support

Need help? Create a ticket on our support page for assistance with any issues or questions.

Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments.

CodeRabbit Commands (Invoked using PR comments)

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai full review to do a full review from scratch and review all the files again.
• @coderabbitai summary to regenerate the summary of the PR.
• @coderabbitai generate docstrings to generate docstrings for this PR.
• @coderabbitai generate sequence diagram to generate a sequence diagram of the changes in this PR.
• @coderabbitai resolve resolve all the CodeRabbit review comments.
• @coderabbitai configuration to show the current CodeRabbit configuration for the repository.
• @coderabbitai help to get help.

Other keywords and placeholders

• Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.
• Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
• Add @coderabbitai anywhere in the PR title to generate the title automatically.

CodeRabbit Configuration File (.coderabbit.yaml)

• You can programmatically configure CodeRabbit by adding a .coderabbit.yaml file to the root of your repository.
• Please see the configuration documentation for more information.
• If your editor has YAML language server enabled, you can add the path at the top of this file to enable auto-completion and validation: # yaml-language-server: $schema=https://coderabbit.ai/integrations/schema.v2.json

Documentation and Community

• Visit our Documentation for detailed information on how to use CodeRabbit.
• Join our Discord Community to get help, request features, and share feedback.
• Follow us on X/Twitter for updates and announcements.

[bjosv]

LGTM, easiest fix for now.