The functions mbedtls_pk_sign(), mbedtls_pk_sign_restartable(),
mbedtls_ecdsa_write_signature() and mbedtls_ecdsa_write_signature_restartable()
now take an extra parameter indicating the size of the output buffer for the
signature.
No change to RSA because for RSA, the output size is trivial to calculate.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add two functions mbedtls_dhm_get_len() and mbedtls_dhm_get_bitlen() to
query the length of the modulus in bytes or bits.
Remove the len field: the cost of calling mbedtls_dhm_get_len() each time
it's needed is negligible, and this improves the abstraction of the DHM
module.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Conflicts:
include/mbedtls/ssl.h
include/psa/crypto_struct.h
Conflicts fixed by using the code from development branch
and manually re-applying the MBEDTLS_PRIVATE wrapping.
Remove padding parameters as mbedtls_rsa_init()
cannot return an error code when padding
parameters are invalid.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This change enables automatic detection and consumption of Mbed TLS
library targets from within other CMake projects. By generating an
`MbedTLSConfig.cmake` file, consuming projects receive a more complete
view of these targets, allowing them to be used as dependencies which
properly inherit the transitive dependencies of the libraries.
This is fairly fragile, as it seems Mbed TLS's libraries do not appear
to properly model their dependencies on other targets, including
third-party dependencies. It is, however, sufficient for building and
linking the compiled Mbed TLS libraries when there are no third-party
dependencies involved. Further work is needed for more complex
use-cases, but this will likely meet the needs of most projects.
Resolves#298. Probably useful for #2857.
Signed-off-by: Chris Kay <chris.kay@arm.com>
MBEDTLS_ECP_FIXED_POINT_OPTIM aims to speed up ecc multiplication performance.
We compute the comb table in runtime now. It is a costly operation.
This patch add a pre-computed table to initialize well-known curves. It speed up ECDSA signature verify process in runtime by using more ROM size.
Signed-off-by: kXuan <kxuanobj@gmail.com>
The introduction of positive options to control the presence
of pre-existing functionality breaks the build for users of
handwritten configurations.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
Introduce MBEDTLS_X509_INFO to indicate the availability of the
mbedtls_x509_*_info() function and closely related APIs. When this is
not defined, also omit name and description from
mbedtls_oid_descriptor_t, and omit OID arrays, macros, and types that
are entirely unused. This saves several KB of code space.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
Signed-off-by: Chris Jones <christopher.jones@arm.com>
According to the design in psa-driver-interface.md. Compiles without
issue in test_psa_crypto_drivers.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
`entropy_poll.h` and `md_wrap.h` were still being used in some of the
example programs. As these headers are now internal, remove their
references and replace them with publicly available functions.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
`entropy_poll.h` is not supposed to be used by application code and
is therefore being made internal.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
`aesni.h` is an internal header and is moved accordingly.
Also removes some references to internal headers in scripts with
only public headers.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Move `include/mbedtls/bn_mul.h` to `library/bn_mul.h`.
Update includes and references to `bn_mul.h` to new location.
Also remove internal headers from `cpp_dummy_build.cpp` as it should only
test public headers in the library.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Simple find and replace using `#include (<|")mbedtls/(.*)_internal.h(>|")`
and `#include $1$2_internal.h$3`.
Also re-generated visualc files by running
`scripts/generate_visualc_files.pl`.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Only move `rsa_internal.h` for now to test dependancies. Other internal
headers will be moved in following commits.
Signed-off-by: Chris Jones <christopher.jones@arm.com>
Part of build_default_make_gcc_and_cxx compares the list of headers
included by `programs/test/cpp_dummy_build.cpp` and the actual headers
present. Add in the missing `mbedtls/psa_config.h` file to this list so
that this test passes.
Signed-off-by: David Brown <david.brown@linaro.org>
Declaring query_config() belongs with the query_config program, not in
ssl_test_lib.h, so move the declaration to a new header file
query_config.h.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
If you pass a curve name to the benchmark program, the ECDH and ECDSA
benchmarks will only run for that particular curve. By default, all
curves are benchmarked.
To simplify the implementation, if you pass multiple curves, only the
last one will be benchmarked.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The driver interfaces described in crypto_accel_driver.h and
crypto_entropy_driver.h are no longer being worked on. We do not
intend to finish the design of these interfaces or to implement them
in Mbed TLS. They have been superseded by the unified driver
interface (docs/proposed/psa-driver-interface.md), which is being
actively worked on both to finalize the specification and to implement
it in Mbed TLS.
The partially implemented dynamic secure element interface is staying
for now.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
GCC 11 generated the warnings because the parameter `ret_buf`
was declared as `const char[10]`, but some of the arguments
provided in `run_test_snprintf` are shorter literals, like "".
Now the type of `ret_buf` is `const char *`.
Both implementations of `test_snprintf` were fixed.
Signed-off-by: Rodrigo Dias Correa <rodrigo@correas.us>
Allow the user to configure PSA to use HMAC_DRBG even if CTR_DRBG is
available, or to explicitly select the hash algorithm to use for
HMAC_DRBG, by setting MBEDTLS_PSA_HMAC_DRBG_MD_TYPE in config.h.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Create a configuration option for autonomous random drivers, i.e. PSA
crypto drivers that provide a random generator, that have their own
entropy source and do not support injecting entropy from another
source.
This commit only creates the configuration option. Subsequent commits
will add the implementation and tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
In cmake version < 3.0, the SOURCES property on targets cannot be
modified after the target is defined. There are several instances in
the code that were using `target_properties()`, which is not available
in the older versions of cmake. Unfortunately, the workaround in #3801
(381c1078fc) assumes that this SOURCES property can be modified.
Work around this by building up any necessary sources before declaring
the target. This is more awkward, but needed to continue to be able to
support the old versions of cmake.
Fixes#3788.
Signed-off-by: David Brown <david.brown@linaro.org>
CMake versions less than 3.0 do not support the `target_sources`
command. In order to be able to support v2.8.12.2 of cmake, directly
set the SOURCES property instead of using the target_sources command.
A future patch could reverse this, if the project decides to forgo
support for cmake versions less than 3.0.
Fixes#3801
Signed-off-by: David Brown <david.brown@linaro.org>
Allows required targets to have prefixes added to them, so that external
projects can avoid target names clashing.
Signed-off-by: Raef Coles <raef.coles@arm.com>
Since the recent changes required the addition of a new definition
in mbedtls/config.h, we also need to update query_config.c to account
for the new MBEDTLS_PSA_CRYPTO_CONFIG setting.
Signed-off-by: John Durkop <john.durkop@fermatsoftware.com>
With PSA crypto v1.0.0, a volatile key identifier may
contain a owner identifier but no file is associated
to it. Thus rename the type psa_key_file_id_t to
mbedtls_svc_key_id_t to avoid a direct link with a
file when a key identifier involves an owner
identifier.
The new type name is prefixed by mbedtls to highlight
that the type is specific to Mbed TLS implementation
and not defined in the PSA Cryptography API
specification.
The svc in the type name stands for service as this
is the key identifier type from the point of view of
the service providing the Cryptography services.
The service can be completely provided by the present
library or partially in case of a multi-client service.
As a consequence rename as well:
. MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER to
MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
. PSA_KEY_ID_INIT to MBEDTLS_SVC_KEY_ID_INIT
. PSA_KEY_FILE_GET_KEY_ID to MBEDTLS_SVC_KEY_ID_GET_KEY_ID
. psa_key_file_id_make to mbedtls_svc_key_id_make
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
* development:
Update copyright notices to use Linux Foundation guidance
Undef ASSERT before defining it to ensure that no previous definition has sneaked in through included files.
Add ChangeLog entry for X.509 CN-type vulnerability
Improve documentation of cn in x509_crt_verify()
Fix comparison between different name types
Add test: DNS names should not match IP addresses
Remove obsolete buildbot reference in compat.sh
Fix misuse of printf in shell script
Fix added proxy command when IPv6 is used
Simplify test syntax
Fix logic error in setting client port
ssl-opt.sh: include test name in log files
ssl-opt.sh: remove old buildbot-specific condition
ssl-opt.sh: add proxy to all DTLS tests
Signed-off-by: Dan Handley <dan.handley@arm.com>
Currently the new component in all.sh fails because
mbedtls_ssl_cf_memcpy_offset() is not actually constant flow - this is on
purpose to be able to verify that the new test works.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
As a result, the copyright of contributors other than Arm is now
acknowledged, and the years of publishing are no longer tracked in the
source files.
Also remove the now-redundant lines declaring that the files are part of
MbedTLS.
This commit was generated using the following script:
# ========================
#!/bin/sh
# Find files
find '(' -path './.git' -o -path './3rdparty' ')' -prune -o -type f -print | xargs sed -bi '
# Replace copyright attribution line
s/Copyright.*Arm.*/Copyright The Mbed TLS Contributors/I
# Remove redundant declaration and the preceding line
$!N
/This file is part of Mbed TLS/Id
P
D
'
# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
This option allows to test the constant-flow nature of selected code, using
MemSan and the fundamental observation behind ctgrind that the set of
operations allowed on undefined memory by dynamic analysers is the same as the
set of operations allowed on secret data to avoid leaking it to a local
attacker via side channels, namely, any operation except branching and
dereferencing.
(This isn't the full story, as on some CPUs some instructions have variable
execution depending on the inputs, most notably division and on some cores
multiplication. However, testing that no branch or memory access depends on
secret data is already a good start.)
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Use list of executables to:
- factorize the code to define executables
- highlight the similarities and differences of the executable definitions
- avoid list duplication
Use alphabetic order for executables in lists.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
The path to source files were relative which triggered
warnings when generating the build system.
Move to absolute paths based on CMAKE_CURRENT_SOURCE_DIR.
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit was generated using the following script:
# ========================
#!/bin/sh
# Find scripts
find -path './.git' -prune -o '(' -name '*.gdb' -o -name '*.pl' -o -name '*.py' -o -name '*.sh' ')' -print | xargs sed -i '
# Remove Mbed TLS declaration if it occurs before the copyright line
1,/Copyright.*Arm/I {
/This file is part of/,$ {
/Copyright.*Arm/I! d
}
}
# Convert non-standard header in scripts/abi_check.py to the format used in the other scripts
/"""/,/"""/ {
# Cut copyright declaration
/Copyright.*Arm/I {
h
N
d
}
# Paste copyright declaration
/"""/ {
x
/./ {
s/^/# / # Add #
x # Replace orignal buffer with Copyright declaration
p # Print original buffer, insert newline
i\
s/.*// # Clear original buffer
}
x
}
}
/Copyright.*Arm/I {
# Print copyright declaration
p
# Read the two lines immediately following the copyright declaration
N
N
# Insert Apache header if it is missing
/SPDX/! {
i\
# SPDX-License-Identifier: Apache-2.0\
#\
# Licensed under the Apache License, Version 2.0 (the "License"); you may\
# not use this file except in compliance with the License.\
# You may obtain a copy of the License at\
#\
# http://www.apache.org/licenses/LICENSE-2.0\
#\
# Unless required by applicable law or agreed to in writing, software\
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT\
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\
# See the License for the specific language governing permissions and\
# limitations under the License.
# Insert Mbed TLS declaration if it is missing
/This file is part of/! i\
#\
# This file is part of Mbed TLS (https://tls.mbed.org)
}
# Clear copyright declaration from buffer
D
}
'
# ========================
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
Instead, we insert a comment containing GDB_BREAK_HERE in the line we
want to break at, and let the gdb script search for it.
Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
No effect so far, except on dependency checking, as the feature it's meant to
disable isn't implemented yet (so the descriptions in config.h and the
ChangeLog entry are anticipation for now).
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
Invasive testing strategy
Create a new header `common.h`.
Introduce a configuration option `MBEDTLS_TEST_HOOKS` for test-specific code, to be used in accordance with the invasive testing strategy.
This is to avoid confusion with the class of macros
MBEDTLS_SSL_PROTO_TLS1_X
which have an underscore between major and minor version number.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
When building with MBEDTLS_MEMORY_DEBUG enabled, and running the ecdh part,
the benchmark program would start writing a very large number of space
characters on stdout, and would have to be killed because it never seemed to
terminate.
This was due to an integer overflow in computing how many space to leave after
the title in order to get memory measurements aligned, which resulted in up
to SIZE_MAX spaces being printed.
This commit just fixes the overflow, the next commit is going to fix the magic
number (12).
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
The server must check client reachability (we chose to do that by checking a
cookie) before destroying the existing association (RFC 6347 section 4.2.8).
Let's make sure we do, by having a proxy-in-the-middle inject a ClientHello -
the server should notice, but not destroy the connection.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
When this option is enabled, the product includes additional
interfaces that enable additional tests. This option should not be
enabled in production, but is included in the "full" build to enable
the extra tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Merge the latest state of the target branch (mbedtls/development) into the
pull request to merge mbed-crypto into mbedtls.
Conflicts:
* ChangeLog: add/add conflict. Resolve by using the usual section order.
Merge `unremove-non-crypto` into `mbedtls/development`. The branch
`unremove-non-crypto` was obtained by starting from `mbed-crypto/development`,
then reverting many commits that removed X.509 and TLS functionality when Mbed
Crypto forked from Mbed TLS (the “unremoval”), then make a few tweaks to
facilitate the merge.
The unremoval step restored old versions of some tls files. If a file doesn't
exist in mbed-crypto, check out the mbedtls version, regardless of what
happened during the unremoval of tls files in the crypto tree. Also
unconditionally take the mbedtls version of a few files where the
modifications are completely project-specific and are not relevant in
mbed-crypto:
* `.github/issue_template.md`: completely different. We may want to reconcile
them independently as a follow-up.
* `.travis.yml`: would only be reverted to an earlier tls version.
* `README.md`: completely different. We may want to reconcile them
independently as a follow-up.
* `doxygen/input/doc_mainpage.h`: the changes in crypto were minimal and not
relevant except as a stopgap as mbed-crypto did not have its own product
versioning in the Doxygen documentation.
* `tests/.jenkins/Jenkinsfile`: completely different.
* `tests/data_files/Makefile`: there were no changes in mbed-crypto,
but the unremoval step restored an old version.
Shell script for everything to do after the merge apart from the conflict
resolution:
```
tls_files=($(comm -23 <(git ls-tree -r --name-only HEAD) <(git ls-tree -r --name-only $(git merge-base upstream-crypto/development MERGE_HEAD))))
tls_files+=($tls_files .github/issue_template.md .travis.yml README.md doxygen/input/doc_mainpage.h tests/.jenkins/Jenkinsfile tests/data_files/Makefile)
git checkout --theirs HEAD -- $tls_files
git add -- $tls_files
```
Resolve the remaining conflicts:
* `library/CMakeLists.txt`:
* Keep the TLS definition of `src_crypto`
* `USE_SHARED_MBEDTLS_LIBRARY`: keep all three libraries, with both
`include` and `crypto/include` in `target_include_directories`, all with
version `2.21.0`.
* `programs/Makefile`:
* Reconcile the APPS lists (add/add from a differently-formatted common
ancestor): insert the `psa/*` from crypto into the tls list.
* Keep the `fuzz` target defined only in tls version.
* Keep the recipe (only in tls version) cleaning `ssl_pthread_server`
stuff for the `clean` target.
* `scripts/config.py`:
* `include_in_full`: add/add conflict. Keep both.
* `tests/scripts/all.sh`:
* `component_test_no_use_psa_crypto_full_cmake_asan`: partially old
version in crypto. Take the tls version.
* `component_test_malloc_0_null` and more: take
`component_test_malloc_0_null` from crypto (with `config.py` rather than
`config.pl`, and with `$ASAN_FLAGS` rather than an explicit list), but
add the call to `ssl-opt.sh` from tls. Take the other components from
crypto.
With this commit, building and running the unit tests with both `make ` and
`cmake` work in the default configuration on Linux. Other platforms, build
systems and configurations are likely not to work, and there is some
regression in test coverage.
There is some loss of functionality because the unremoval step restored older
versions of tls content. This commit contains the latest tls version of
tls-only files, but some changes from the tls side in files that existed on
both sides have regressed. Most problematic changes are hunks that remove some
tls-specific feature and contain either a C preprocessor symbol identifying a
tls-specific module or option, or the name of a tls-specific file. Hunks
that remove a tls-specific preprocessor symbol can be identified with the
regular expression `^-.*MBEDTLS_(ERR_)?(PKCS11|X509|NET|SSL)_`.
Subsequent commits will revert a few parts of the patch from this merge commit
in order to restore the tls functionality that it removes, ensure that the
test coverage includes what was covered in either branch, and fix test
failures.
Even if other higher-level libraries were added, these programs would
only link with the crypto library, which is the one that contains
platform functions.
This reverts commit d832f187f7.
Conflicts:
* CMakeLists.txt:
* USE_PKCS11_HELPER_LIBRARY: there has been a change immediately before
where it was removed. Just re-add what was removed.
* tests/CMakeLists.txt:
* USE_PKCS11_HELPER_LIBRARY: there has been a change immediately before
where it was removed. Just re-add what was removed.
This reverts commit d874a1fd14.
Conflicts:
* CMakeLists.txt:
* ENABLE_ZLIB_SUPPORT: there has been a change immediately after
where it was removed. Just re-add what was removed.
* tests/CMakeLists.txt:
* ENABLE_ZLIB_SUPPORT: there has been a change immediately after
where it was removed. Just re-add what was removed.
This reverts commit 1c66e48670.
Conflicts:
* include/mbedtls/check_config.h:
* MBEDTLS_SSL_PROTO_SSL3: there has been an addition (of
MBEDTLS_SHA512_NO_SHA384) at the place where it was removed. Re-add it
after (alphabetical order).
* MBEDTLS_ENABLE_WEAK_CIPHERSUITES: there has been an addition (of
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY) at the place where it was removed.
Re-add it after (alphabetical order).
* MBEDTLS_SSL_ALL_ALERT_MESSAGES: there has been an addition (of
MBEDTLS_SHA512_SMALLER) at the place where it was removed. Re-add it
after (alphabetical order).
* include/mbedtls/config.h:
* MBEDTLS_ENABLE_WEAK_CIPHERSUITES: there has been an addition (of
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY) at the place where it was removed.
Re-add it after (alphabetical order).
* MBEDTLS_SSL_ALL_ALERT_MESSAGES: there has been an addition (of
MBEDTLS_SHA512_SMALLER) at the place where it was removed. Re-add it
after (alphabetical order).
* library/version_features.c: re-generate by running
scripts/generate_features.pl.
* programs/test/query_config.c: re-generate by running
scripts/generate_query_config.pl.
* scripts/config.pl: this file has been replaced by config.py. Port
the reversed changes to config.py:
* Revert removing three symbols from the list of symbols to
exclude from full.
* Revert removing one symbol (MBEDTLS_NET_C) from the list of symbols
to exclude from baremetal.
* scripts/footprint.sh:
* Re-add the line to unset MBEDTLS_NET_C, but with config.py instead of
config.pl.
* tests/scripts/all.sh:
* component_test_no_platform: re-add the line to unset MBEDTLS_NET_C, but
with config.py instead of config.pl.
* component_build_arm_none_eabi_gcc,
component_build_arm_none_eabi_gcc_no_udbl_division,
component_build_arm_none_eabi_gcc_no_64bit_multiplication,
component_build_armcc: these components now use the baremetal
configuration, so they do not need to turn off MBEDTLS_NET_C explicitly.
This reverts commit bb1f701212.
* include/mbedtls/check_config.h:
* MBEDTLS_X509_RSASSA_PSS_SUPPORT: there has been an addition (of
MBEDTLS_SHA512_NO_SHA384) at the place where it was removed.
Re-add it before MBEDTLS_SHA512_NO_SHA384 to keep it grouped
with MBEDTLS_RSA_C.
Conflicts:
* scripts/config.pl: this file has been replaced by config.py. Port
the reversed changes to config.py:
* Revert removing three symbols from the list of symbols to
exclude from full.
Add a very basic test of calloc to the selftest program. The selftest
program acts in its capacity as a platform compatibility checker rather
than in its capacity as a test of the library.
The main objective is to report whether calloc returns NULL for a size
of 0. Also observe whether a free/alloc sequence returns the address
that was just freed and whether a size overflow is properly detected.
You can't reuse a CTR_DRBG context without free()ing it and
re-init()ing. This generally happened to work, but was never
guaranteed. It could have failed with alternative implementations of
the AES module because mbedtls_ctr_drbg_seed() calls
mbedtls_aes_init() on a context which is already initialized if
mbedtls_ctr_drbg_seed() hasn't been called before, plausibly causing a
memory leak. Calling free() and seed() with no intervening init fails
when MBEDTLS_THREADING_C is enabled and all-bits-zero is not a valid
mutex representation. So add the missing free() and init().
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.
As the SSL programs, like ssl_client2 and ssl_server2, are dependent on
SSL and therefore about to be removed, the only consumer of query_config
is the query_compile_time_config test. As such, it makes sense to move
query_config to be next to what uses it.
You can't reuse a CTR_DRBG context without free()ing it and
re-init()ing. This generally happened to work, but was never
guaranteed. It could have failed with alternative implementations of
the AES module because mbedtls_ctr_drbg_seed() calls
mbedtls_aes_init() on a context which is already initialized if
mbedtls_ctr_drbg_seed() hasn't been called before, plausibly causing a
memory leak. Calling free() and seed() with no intervening init fails
when MBEDTLS_THREADING_C is enabled and all-bits-zero is not a valid
mutex representation. So add the missing free() and init().
Add a very basic test of calloc to the selftest program. The selftest
program acts in its capacity as a platform compatibility checker rather
than in its capacity as a test of the library.
The main objective is to report whether calloc returns NULL for a size
of 0. Also observe whether a free/alloc sequence returns the address
that was just freed and whether a size overflow is properly detected.
