Linux/Aarch64: support SHA acceleration detection with older libc
On Linux on aarch64 (64-bit ARMv8) processors, we use getauxval() to detect
whether the runtime environment supports SHA-256 or SHA-512 acceleration.
Some libc do not define the necessary HWCAP_xxx constants to analyze the
result of getauxval(), either because they don't bother or because they're
too old to recognize the values we need (for example, HWCAP_SHA2 appeared in
Glibc 2.24 and HWCAP_SHA512 appeared in Glibc 2.27). In such cases, assume
that the values are the same as in the kernel ABI and define the constants
manually.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
`gcc-14` added a new `-Wcalloc-transposed-args` warning recently. It
detected minor infelicity in `calloc()` API usage in `mbedtls`:
In file included from /build/mbedtls/tests/include/test/ssl_helpers.h:19,
from /build/mbedtls/tests/src/test_helpers/ssl_helpers.c:11:
/build/mbedtls/tests/src/test_helpers/ssl_helpers.c: In function 'mbedtls_test_init_handshake_options':
/build/mbedtls/tests/include/test/macros.h:128:46:
error: 'calloc' sizes specified with 'sizeof' in the earlier argument
and not in the later argument [-Werror=calloc-transposed-args]
128 | (pointer) = mbedtls_calloc(sizeof(*(pointer)), \
| ^
Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Upon further consideration we think that a remote attacker close to the
victim might be able to have precise enough timing information to
exploit the side channel as well. Update the Changelog to reflect this.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Any timing variance dependant on the output of this function enables a
Bleichenbacher attack. It is extremely difficult to use safely.
In the Marvin attack paper
(https://people.redhat.com/~hkario/marvin/marvin-attack-paper.pdf) the
author suggests that implementations of PKCS 1.5 decryption that don't
include a countermeasure should be considered inherently dangerous.
They suggest that all libraries implement the same countermeasure, as
implementing different countermeasures across libraries enables the
Bleichenbacher attack as well.
This is extremely fragile and therefore we don't implement it. The use
of PKCS 1.5 in Mbed TLS implements the countermeasures recommended in
the TLS standard (7.4.7.1 of RFC 5246) and is not vulnerable.
Add a warning to PKCS 1.5 decryption to warn users about this.
Signed-off-by: Janos Follath <janos.follath@arm.com>
