Fix incorrect checks of cn_cbor_encoder_write result. (#52)

cn_cbor_encoder_write returns -1 on error. In several cases any
non-zero result was treated as success. In two cases, a -1 result
would be converted to size_t and returned when a 0 result should
be returned.
5 files changed
tree: 04692ab6e69898f9126a62de889c6021d6fd9e23
  1. .appveyor.yml
  2. .gitignore
  3. .travis.yml
  4. CMakeLists.txt
  5. Coverity_Model.c
  6. Doxyfile.in
  7. LICENSE
  8. README.md
  9. build.sh
  10. cmake/
  11. dumper/
  12. src/
  13. test/
README.md

COSE-C Implementation Build Status Coverage Status Coverity Status

This project is a C implementation of the IETF CBOR Encoded Message Syntax (COSE). There are currently two versions of the COSE document that can be read. The most current work in progress draft can be found on github in the cose-wg/cose-spec project. The IETF also keeps a copy of the spec in the COSE WG.

The project is using the CN-CBOR project to provide an implementation of the Concise Binary Object Representation or CBOR.

The project is using OpenSSL for the cryptographic primitives.

Contributing

Go ahead, file issues, make pull requests.

Building

The project is setup to build using CMake. The way that the CMake files are setup, it requires that version 3.0 or higher is used.

The project requires the use of cn-cbor(https://github.com/cabo/cn-cbor) in order to build. The CMake configuration files will automatically pull down the correct version when run.

Memory Model

The memory model used in this library is a mess. This is in large part because the memory model of cn-cbor is still poorly understood.

There are three different memory models that can be used with cn-cbor and cose-c, at this time only one of them is going to produce good results for long running systems.

The cn-cbor project was built with a specific memory model, but did not limit itself to that memory model when writing the code. It was originally designed for working on small devices that use a block allocator with sub-allocations done from that allocated block. This allows for all of the items allocated in that large block to be freed in a single operation when everything is done.

  • Build without USE_CONTEXT: This model uses standard calloc/free and suffers from the cn-cbor memory model problems.

  • Build with USE_CONTEXT and pass in NULL: This model is equivalent to the previous configuration.

  • Build with USE_CONTEXT and pass in a block allocator: This model works, but requires that you provide the allocator.