It works in practice on almost every platform, given that we're only
using the wrong type in cases where the value is guaranteed to stay
within the value bits of a signed int. But even in this case it may or
may not be strictly conforming. Anyway `gcc -std=c99 -pedantic`
rejects it.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When building with CMake, for sample programs that only use
functionality in libmbedcrypto (i.e. crypto and platform), link with
libmbedcrypto, not with libmbedtls.
This doesn't change the result, because the linker skips libraries in
which no symbol is used, but it changes the build dependencies, and it
has the advantage of bringing programs/*/CMakeLists.txt closer to the
corresponding files under crypto/.
The programs concerned are crypto sample and test programs, and
programs that only use (potential) platform functions such as
mbedtls_printf. dh_client and dh_server keep linking with mbedtls
because they use functions from the net_sockets module.
This is done to account for platforms, for which we want custom behavior
upon the program termination, hence we call `mbedtls_exit()` instead of
returning from `main()`.
All sample and test programs had a definition of mbedtls_param_failed.
This was necessary because we wanted to be able to build them in a
configuration with MBEDTLS_CHECK_PARAMS set but without a definition
of MBEDTLS_PARAM_FAILED. Now that we activate the sample definition of
MBEDTLS_PARAM_FAILED in config.h when testing with
MBEDTLS_CHECK_PARAMS set, this boilerplate code is no longer needed.
The previous prototype gave warnings are the strings produced by #cond and
__FILE__ are const, so we shouldn't implicitly cast them to non-const.
While at it modifying most example programs:
- include the header that has the function declaration, so that the definition
can be checked to match by the compiler
- fix whitespace
- make it work even if PLATFORM_C is not defined:
- CHECK_PARAMS is not documented as depending on PLATFORM_C and there is
no reason why it should
- so, remove the corresponding #if defined in each program...
- and add missing #defines for mbedtls_exit when needed
The result has been tested (make all test with -Werror) with the following
configurations:
- full with CHECK_PARAMS with PLATFORM_C
- full with CHECK_PARAMS without PLATFORM_C
- full without CHECK_PARAMS without PLATFORM_C
- full without CHECK_PARAMS with PLATFORM_C
Additionally, it has been manually tested that adding
mbedtls_aes_init( NULL );
near the normal call to mbedtls_aes_init() in programs/aes/aescrypt2.c has the
expected effect when running the program.
The sample programs require an additional handler function of
mbedtls_param_failed() to handle any failed parameter validation checks enabled
by the MBEDTLS_CHECK_PARAMS config.h option.
This commit replaces multiple `memset()` calls in the example
programs aes/aescrypt2.c and aes/crypt_and_hash.c by calls to
the reliable zeroization function `mbedtls_zeroize()`.
While not a security issue because the code is in the example
programs, it's bad practice and should be fixed.
The AES sample application programs/aes/aescrypt2 could miss zeroizing
the stack-based key buffer in case of an error during operation. This
commit fixes this and also clears another temporary buffer as well as
all command line arguments (one of which might be the key) before exit.
The AES sample application programs/aes/crypt_and_hash could miss
zeroizing the stack-based key buffer in case of an error during
operation. This commit fixes this and also clears all command line
arguments (one of which might be the key) before exit.
* Fix crypt_and_hash to support decrypting GCM encrypted files
* Fix documentation in crypt_and_hash for the generic case
* Remove unused lastn from crypt_and_hash
lastn is not used with the cipher layer as it already provides padding
and understanding of length of the original data.
Note from future self: actually md_init_ctx will be re-introduced with the
same signature later, and a new function with the additional argument will be
added.
