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Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
This reverts commit b621fb503c.
Because of the Trusted Firmware design, timing-safe functions are not
needed. Using them may be misleading as it could be interpreted as being
a protection against private data leakage, which isn't the case here.
For each image, the SHA-256 hash is calculated. Some padding is appended
and the result is encrypted with a private key using RSA-2048. This is
the signature of the image. The public key is stored along with BL1 in
read-only memory and the encrypted hash is stored in the FIP.
When authenticating an image, the TF decrypts the hash stored in the FIP
and recalculates the hash of the image. If they don't match, the boot
sequence won't continue.
A constant-time comparison does not provide additional security as all
the data involved in this process is already known to any attacker.
There is no private data that can leaked through a timing attack when
authenticating an image.
`timingsafe_bcmp()` is kept in the codebase because it could be useful
in the future.
Change-Id: I44bdcd58faa586a050cc89447e38c142508c9888
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
To avoid timing side-channel attacks, it is needed to use a constant
time memory comparison function when comparing hashes. The affected
code only cheks for equality so it isn't needed to use any variant of
memcmp(), bcmp() is enough.
Also, timingsafe_bcmp() is as fast as memcmp() when the two compared
regions are equal, so this change incurrs no performance hit in said
case. In case they are unequal, the boot sequence wouldn't continue as
normal, so performance is not an issue.
Change-Id: I1c7c70ddfa4438e6031c8814411fef79fd3bb4df
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
By default ARM TF is built with the '-pedantic' compiler flag, which
helps detecting violations of the C standard. However, the mbed TLS
library and its associated authentication module in TF used to fail
building with this compiler flag. As a workaround, the mbed TLS
authentication module makefile used to set the 'DISABLE_PEDANTIC'
TF build flag.
The compiler errors flagged by '-pedantic' in the mbed TLS library
have been fixed between versions 1.3.9 and 2.2.0 and the library now
properly builds with this compiler flag.
This patch fixes the remaining compiler errors in the mbed TLS
authentication module in TF and unsets the 'DISABLE_PEDANTIC' TF
build flag. This means that TF is now always built with '-pedantic'.
In particular, this patch:
* Removes the final semi-colon in REGISTER_COT() macro.
This semi-colon was causing the following error message:
drivers/auth/tbbr/tbbr_cot.c:544:23: error: ISO C does not allow
extra ';' outside of a function [-Werror=pedantic]
This has been fixed both in the mbed TLS authentication module
as well as in the certificate generation tool. Note that the latter
code didn't need fixing since it is not built with '-pedantic' but
the change has been propagated for consistency.
Also fixed the REGISTER_KEYS() and REGISTER_EXTENSIONS() macros,
which were suffering from the same issue.
* Fixes a pointer type.
It was causing the following error message:
drivers/auth/mbedtls/mbedtls_crypto.c: In function 'verify_hash':
drivers/auth/mbedtls/mbedtls_crypto.c:177:42: error: pointer of
type 'void *' used in arithmetic [-Werror=pointer-arith]
Change-Id: I7b7a04ef711efd65e17b5be26990d1a0d940257d
The mbed TLS library has introduced some changes in the API from
the 1.3.x to the 2.x releases. Using the 2.x releases requires
some changes to the crypto and transport modules.
This patch updates both modules to the mbed TLS 2.x API.
All references to the mbed TLS library in the code or documentation
have been updated to 'mbed TLS'. Old references to PolarSSL have
been updated to 'mbed TLS'.
User guide updated to use mbed TLS 2.2.0.
NOTE: moving up to mbed TLS 2.x from 1.3.x is not backward compatible.
Applying this patch will require an mbed TLS 2.x release to be used.
Also note that the mbed TLS license changed to Apache version 2.0.
Change-Id: Iba4584408653cf153091f2ca2ee23bc9add7fda4
This patch adds the following mbedTLS based libraries:
* Cryptographic library
It is used by the crypto module to verify a digital signature
and a hash. This library relies on mbedTLS to perform the
cryptographic operations. mbedTLS sources must be obtained
separately.
Two key algorithms are currently supported:
* RSA-2048
* ECDSA-SECP256R1
The platform is responsible for picking up the required
algorithm by defining the 'MBEDTLS_KEY_ALG' variable in the
platform makefile. Available options are:
* 'rsa' (for RSA-2048) (default option)
* 'ecdsa' (for ECDSA-SECP256R1)
Hash algorithm currently supported is SHA-256.
* Image parser library
Used by the image parser module to extract the authentication
parameters stored in X509v3 certificates.
Change-Id: I597c4be3d29287f2f18b82846973afc142ee0bf0
dp-arm
Antonio Nino Diaz
Sandrine Bailleux
Juan Castillo