This patch modifies the documentation for mbedtls_ssl_write() to allow
0 as a valid return value as this is the correct number of bytes that
should be returned when an empty TLS Application record is sent.
Fix compilation warnings with IAR toolchain, on 32 bit platform.
Reported by rahmanih in #683
This is based on work by Ron Eldor in PR #750, some of which was independently
fixed by Azim Khan and already merged in PR #1655.
This PR fixes multiple issues in the source code to address issues raised by
tests/scripts/check-files.py. Specifically:
* incorrect file permissions
* missing newline at the end of files
* trailing whitespace
* Tabs present
* TODOs in the souce code
As a protection against the Lucky Thirteen attack, the TLS code for
CBC decryption in encrypt-then-MAC mode performs extra MAC
calculations to compensate for variations in message size due to
padding. The amount of extra MAC calculation to perform was based on
the assumption that the bulk of the time is spent in processing
64-byte blocks, which was correct for most supported hashes but not for
SHA-384. Adapt the formula to 128-byte blocks for SHA-384.
Clarify the roles of the buffer parameter and their sizes.
Remove a statement about input size restrictions that only applies to
mbedtls_gcm_update, not to the whole-message functions.
Document the possible error codes.
Warn that mbedtls_gcm_crypt_and_tag in decrypt mode does not
authenticate the data and recommend using mbedtls_gcm_auth_decrypt
instead.
Fix IAR compiler warnings
Two warnings have been fixed:
1. code 'if( len <= 0xFFFFFFFF )' gave warning 'pointless integer comparison'.
This was fixed by wraping the condition in '#if SIZE_MAX > 0xFFFFFFFF'.
2. code 'diff |= A[i] ^ B[i];' gave warning 'the order of volatile accesses is undefined in'.
This was fixed by read the volatile data in temporary variables before the computation.
Explain IAR warning on volatile access
Consistent use of CMAKE_C_COMPILER_ID