This is a temporary work-around for an integration issue.
A future task will re-integrate randomness into these functions are their
entire point is to be randomized; this is really just temporary.
Record checking fails if mbedtls_ssl_check_record() is called with
external buffer. Received record sequence number is available in the
incoming record but it is not available in the ssl contexts `in_ctr`-
variable that is used when decoding the sequence number.
To fix the problem, temporarily update ssl context `in_ctr` to
point to the received record header and restore value later.
Override define MBEDTLS_ENTROPY_MAX_SOURCES from 1 to 3 in baremetal_test.h
mbedtls_entropy_init adds 2 sources already so max must be 3 so that
one source can be added with mbedtls_entropy_add_source.
-Add config option for AES encyption only to config.h. Feature is
disabled by default.
-Enable AES encrypt only feature in baremetal.h configuration
-Remove AES encypt only feature from full config
- Unset MBEDTLS_PADLOCK_C in aes_only_128_bit_keys test to get RAM
optimised version tested
- Use compiler flag "-O1" instead of "-Wall -Wextra" to see warnings
Do not reserve additionl space for mbedtls_aes_context if config
option AES_ONLY_128_BIT_KEY_LENGTH is used and PADLOCK_C is not used.
This reduces RAM usage by 96 bytes.
In baremetal configuration reserve space for 10 128-bit keys in order
to save 112 bytes of heap.
- Do not include MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH to full config
as it requires also MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
- Update check_config to check availability of flags:
MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH
MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
Ultimately, mbedtls_hardware_poll() is going to be provided by the
OS/environment when running on target. But for on-host programs and tests, we
need to define (a fake version) in each program that we want to be able to
link.
A previous commit took care of ssl_client2 and ssl_server2. But if we want to
be able to compile all programs, we need to modify each of them. This doesn't
seem useful, so instead let's just build the programs we need for testing -
this means only udp_proxy needs fixing in addition to what's already done.
This issue went unnoticed in the PR that introduced the new all.sh component,
because at that time the platform_memxxx() functions were not actually used in
the library (nor in programs), so the linker could live with
mbedtls_hardware_poll() not being defined, as it wasn't called anywhere. This
changed when we started using the new platform_memxxx() functions in the
library.
- out_ctr is public because it's transmited over the wire in DTLS (and in TLS
it can be inferred by a passive network attacker just by counting records).
- handshake mask is not a secret because it can be inferred by a passive
network attacker just logging record sequence number seen so far.
This commits reverts to plain memset() for cases like:
some_type foo;
memset( &foo, 0, sizeof( foo ) );
(Sometimes there is code between declaration in memset(), but it doesn't
matter as long as it doesn't touch foo.)
The reasoning is the same as in the previous commit: the stack shouldn't
contain sensitive data as we carefully wipe it after use.
We call xxx_init() on a structure when it has been freshly allocated (on the
stack or heap).
At this point it contains random-looking data none of which should be
sensitive, as all sensitive data is wiped using mbedtls_platform_zeroize()
when we're done using it and the memory area is going to be reclaimed (by
exiting the function or free()ing the buffer).
Add it in all files that use mbedtls_plaform_memset() but didn't already
include platfom_util.h.
In some configurations it just happened to work, either because it was
included indirectly or because the part of the code that used that function
was disabled, but it some configurations it broke, so let's fix it properly.
Steps:
1. sed -i 's/\bmemset(\([^)]\)/mbedtls_platform_memset(\1/g' library/*.c tinycrypt/*.c include/mbedtls/*.h scripts/data_files/*.fmt
2. Manually edit library/platform_util.c to revert to memset() in the
implementations of mbedtls_platform_memset() and mbedtls_platform_memcpy()
3. egrep -n '\<memset\>' library/*.c include/mbedtls/*.h tinycrypt/*.c
The remaining occurrences are in three categories:
a. From point 2 above.
b. In comments.
c. In the initialisation of memset_func, to be changed in a future commit.
This commit modifies the example programs ssl_client2 and ssl_server2
to allocate various structures on the heap instead of the stack. This
allows more fine-grained memory usage tracking via valgrind massif.
