The following provides more information on this PR:
- PSA stands for Platform Security Architecture.
- Add support for use of psa_trusted_storage_api internal_trusted_storage.h v1.0.0
as the interface to the psa_trusted_storage_linux backend (i.e. for persistent
storage when MBEDTLS_PSA_ITS_FILE_C is not defined). This requires changes
to psa_crypto_its.h and psa_crypto_storage.c to migrate to the new API.
Stored keys must contain lifetime information. The lifetime used to be
implied by the location of the key, back when applications supplied
the lifetime value when opening the key. Now that all keys' metadata
are stored in a central location, this location needs to store the
lifetime explicitly.
Pass information via a key attribute structure rather than as separate
parameters to psa_crypto_storage functions. This makes it easier to
maintain the code when the metadata of a key evolves.
This has negligible impact on code size (+4B with "gcc -Os" on x86_64).
Key creation and key destruction for a key in a secure element both
require updating three pieces of data: the key data in the secure
element, the key metadata in internal storage, and the SE driver's
persistent data. Perform these actions in a transaction so that
recovery is possible if the action is interrupted midway.
Implement a transaction record that can be used for actions that
modify more than one piece of persistent data (whether in the
persistent storage or elsewhere such as in a secure element).
While performing a transaction, the transaction file is present in
storage. If the system starts with an ongoing transaction, it must
complete the transaction (not implemented yet).
In the generic message digest abstraction, instead of storing method
pointers in the per-algorithm data structure and using wrapper
functions as those methods, call the per-algorithm function directly.
This saves some code size (2336B -> 2043B for md with all algorithms
enabled on M0+ with gcc -Os). This should also make it easier to
optimize the case when a single algorithm is supported. In addition,
this is a very slight security improvement since it removes one
opportunity for a buffer overflow to directly turn into letting the
attacker overwrite a pointer to a function pointer.
This commit does not modify the documented API. However, it removes
the possibility for users to define their own hash implementations and
use them by building their own md_info.
Changing mbedtls_md_context to contain a md type identifier rather
than a pointer to an info structure would save a few more bytes and a
few more runtime memory accesses, but would be a major API break since
a lot of code uses `const mbedtls_md_info *` to keep track of which
hash is in use.
All modules using restartable ECC operations support passing `NULL`
as the restart context as a means to not use the feature.
The restart contexts for ECDSA and ECP are nested, and when calling
restartable ECP operations from restartable ECDSA operations, the
address of the ECP restart context to use is calculated by adding
the to the address of the ECDSA restart context the offset the of
the ECP restart context.
If the ECP restart context happens to not reside at offset `0`, this
leads to a non-`NULL` pointer being passed to restartable ECP
operations from restartable ECDSA-operations; those ECP operations
will hence assume that the pointer points to a valid ECP restart
address and likely run into a segmentation fault when trying to
dereference the non-NULL but close-to-NULL address.
The problem doesn't arise currently because luckily the ECP restart
context has offset 0 within the ECDSA restart context, but we should
not rely on it.
This commit fixes the passage from restartable ECDSA to restartable ECP
operations by propagating NULL as the restart context pointer.
Apart from being fragile, the previous version could also lead to
NULL pointer dereference failures in ASanDbg builds which dereferenced
the ECDSA restart context even though it's not needed to calculate the
address of the offset'ed ECP restart context.
All modules using restartable ECC operations support passing `NULL`
as the restart context as a means to not use the feature.
The restart contexts for ECDSA and ECP are nested, and when calling
restartable ECP operations from restartable ECDSA operations, the
address of the ECP restart context to use is calculated by adding
the to the address of the ECDSA restart context the offset the of
the ECP restart context.
If the ECP restart context happens to not reside at offset `0`, this
leads to a non-`NULL` pointer being passed to restartable ECP
operations from restartable ECDSA-operations; those ECP operations
will hence assume that the pointer points to a valid ECP restart
address and likely run into a segmentation fault when trying to
dereference the non-NULL but close-to-NULL address.
The problem doesn't arise currently because luckily the ECP restart
context has offset 0 within the ECDSA restart context, but we should
not rely on it.
This commit fixes the passage from restartable ECDSA to restartable ECP
operations by propagating NULL as the restart context pointer.
Apart from being fragile, the previous version could also lead to
NULL pointer dereference failures in ASanDbg builds which dereferenced
the ECDSA restart context even though it's not needed to calculate the
address of the offset'ed ECP restart context.
dummy
Replace some frequently-used macros by inline functions: instead of
calling MOD_{ADD,SUB,MUL} after the mbedtls_mpi_{add,sub,mul}_mpi,
call a function mbedtls_mpi_xxx_mod that does the same.
In the baremetal config, with "gcc -Os -mthumb -mcpu=cortex-m0plus",
ecp.o goes down from 13878 bytes to 12234.
No noticeable performance change for benchmarks on x86_64 with either
"gcc -O2" or "gcc -Os".
When creating a key with a lifetime that places it in a secure
element, retrieve the appropriate driver table entry.
This commit doesn't yet achieve behavior: so far the code only
retrieves the driver, it doesn't call the driver.
Expose the type of an entry in the SE driver table as an opaque type
to other library modules. Soon, driver table entries will have state,
and callers will need to be able to access this state through
functions using this opaque type.
Provide functions to look up a driver by its lifetime and to retrieve
the method table from an entry.
Remove use of CMAKE_SOURCE_DIR in case mbedtls is built from within
another CMake project. Define MBEDTLS_DIR to ${CMAKE_CURRENT_SOURCE_DIR}
in the main CMakeLists.txt file and refer to that when defining target
include paths to enable mbedtls to be built as a sub project.
Fixes#2609
Signed-off-by: Ashley Duncan <ashes.man@gmail.com>
Signed-off-by: Jaeden Amero <jaeden.amero@arm.com>
* origin/development: (33 commits)
Test with MBEDTLS_ECP_RESTARTABLE
Allow TODO in code
Use the docstring in the command line help
Split _abi_compliance_command into smaller functions
Record the commits that were compared
Document how to build the typical argument for -s
Allow running /somewhere/else/path/to/abi_check.py
Warn if VLAs are used
Remove redundant compiler flag
Consistently spell -Wextra
Update Mbed Crypto to contain mbed-crypto#152
Improve compatibility with firewalled networks
Dockerfile: apt -> apt-get
Change Docker container to bionic
Clean up file prologue comments
Add docker-based test scripts
ChangeLog: Add ChangeLog entry for #2681
Allow declarations after statements
CMake: Add a subdirectory build regression test
README: Enable builds as a CMake subproject
...
* origin/pr/2706:
Update Mbed Crypto to contain mbed-crypto#152
CMake: Add a subdirectory build regression test
README: Enable builds as a CMake subproject
ChangeLog: Enable builds as a CMake subproject
Remove use of CMAKE_SOURCE_DIR
* origin/pr/2632:
Adapt ChangeLog
Avoid use of large stack buffers in mbedtls_x509_write_crt_pem()
Improve documentation of mbedtls_pem_write_buffer()
Perform CRT writing in-place on the output buffer
Adapt x509write_crt.c to coding style
The failure of mbedtls_md was not checked in one place. This could have led
to an incorrect computation if a hardware accelerator failed. In most cases
this would have led to the key exchange failing, so the impact would have been
a hard-to-diagnose error reported in the wrong place. If the two sides of the
key exchange failed in the same way with an output from mbedtls_md that was
independent of the input, this could have led to an apparently successful key
exchange with a predictable key, thus a glitching md accelerator could have
caused a security vulnerability.
The window size variable in ecp_pick_window_size() can take values
4, 5 or 6, but we clamp it not to exceed the value of
MBEDTLS_ECP_WINDOW_SIZE. If that is 6 (default) or higher, the
static analyzer will point out that the test:
w > MBEDTLS_ECP_WINDOW_SIZE always evaluates to false.
This commit removes the test for the cases of the window size
large enough to fit all the potential values of the variable.
The psa_tls12_prf_set_seed() and psa_tls12_prf_set_label() functions did
not work on platforms where malloc(0) returns NULL.
It does not affect the TLS use case but these PRFs are used in other
protocols as well and might not be used the same way. For example EAP
uses the TLS PRF with an empty secret. (This would not trigger the bug,
but is a strong indication that it is not safe to assume that certain
inputs to this function are not zero length.)
The conditional block includes the memcpy() call as well to avoid
passing a NULL pointer as a parameter resulting in undefined behaviour.
The current tests are already using zero length label and seed, there is
no need to add new test for this bug.
Secure element support has its own source file, and in addition
requires many hooks in other files. This is a nontrivial amount of
code, so make it optional (but default on).
