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If `MBEDTLS_PLATFORM_SNPRINTF_ALT` isn't used, the function
`mbedtls_platform_set_snprintf()` isn't defined.

In case a platform uses a different mbed TLS configuration file than
the one provided by the Trusted Firmware, and it doesn't define the
mentioned build option, this will result in a build error.

This patch modifies the initialization code so that
`mbedtls_platform_set_snprintf()` is only used if
`MBEDTLS_PLATFORM_SNPRINTF_ALT` is defined, allowing platforms to use
it or not depending on their needs.

Change-Id: I1d5c86d57e9b2871ba463030bf89210ebec5178e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

This patch adds support for RSASSA-PSS Signature Algorithm for
X509 certificates in mbedtls crypto driver. Now the driver supports
RSA PKCS2_1 standard as mandated by TBBR.

NOTE: With this patch, the PKCS1_5 standard compliant RSA signature
is deprecated.

Change-Id: I9cf6d073370b710cc36a7b374a55ec96c0496461
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

The mbedTLS library requires larger heap memory for verification of RSASSA-PSS
signature in certificates during Trusted Board Boot. This patch increases the
heap memory for the same.

Change-Id: I3c3123d7142b7b7b01463516ec436734895da159
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

mbed TLS provides the debug API `mbedtls_memory_buffer_alloc_status()`
to analyse the RAM usage of the library.

When RSA is selected as algorithm, the maximum heap usage in FVP and
Juno has been determined empirically to be approximately 5.5 KiB.
However, The default heap size used when RSA is selected is 8 KiB.

This patch reduces the buffer from 8 KiB to 6 KiB so that the BSS
sections of both BL1 and BL2 are 2 KiB smaller when the firmware is
compiled with TBB support.

Change-Id: I43878a4e7af50c97be9c8d027c728c8483f24fbf
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

The Trusted Firmware uses a subset of the APIs provided by mbed TLS.
This subset internally uses `snprintf`, but the only format specifier
used is '%d', which is supported by `tf_snprintf`.

This patch makes mbed TLS use `tf_snprintf` instead of `snprintf`,
saving 3 KB in both debug and release builds when TBBR is enabled.

Change-Id: I7f992a21015930d7c0f4660e7a28ceefd60b9597
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

This patch renames MBEDTLS_KEY_ALG to TF_MBEDTLS_KEY_ALG. This
completes the migration of TF specific macros so that they do not
have the MBEDTLS_ suffix (see arm-trusted-firmware#874).

Change-Id: Iad7632477e220b0af987c4db3cf52229fb127d00
Signed-off-by: David Cunado <david.cunado@arm.com>

An earlier patch (arm-trusted-firmware#874) migrated MBEDTLS_ suffixed
macros to have a TBBR_ suffix to avoid any potential clash with future
mbedtls macros.

But on reflection the TBBR_ suffix could be confusing as the macros
are used to drive TF-specific configuration of mbedtls. As such
this patch migrates these macros from TBBR_suffix to TF_MBEDTLS_
suffix which more accurately conveys their use.

Change-Id: Ic87642b653ceeaa03d62f724976abd5e12e867d4
Signed-off-by: David Cunado <david.cunado@arm.com>

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/



Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

These macros are not part of mbed TLS so they should not be prefixed
with `MBEDTLS_` to avoid potential collision in the future. Use the
`TBBR_` suffix to highlight that they only used in TF.

`MBEDTLS_KEY_ALG` was not modified because that is documented and used
by platforms to select the key algorithm.

Change-Id: Ief224681715c481691c80810501830ce16e210b0
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

This reverts commit b621fb50

.

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>

Replace all use of memset by zeromem when zeroing moderately-sized
structure by applying the following transformation:
memset(x, 0, sizeof(x)) => zeromem(x, sizeof(x))

As the Trusted Firmware is compiled with -ffreestanding, it forbids the
compiler from using __builtin_memset and forces it to generate calls to
the slow memset implementation. Zeromem is a near drop in replacement
for this use case, with a more efficient implementation on both AArch32
and AArch64.

Change-Id: Ia7f3a90e888b96d056881be09f0b4d65b41aa79e
Signed-off-by: Douglas Raillard <douglas.raillard@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>

In mbedtls_x509_parser.c there are some static arrays that are filled
during the integrity check and then read whenever an authentication
parameter is requested. However, they aren't cleared in case of an
integrity check failure, which can be problematic from a security
point of view. This patch clears these arrays in the case of failure.

Change-Id: I9d48f5bc71fa13e5a75d6c45b5e34796ef13aaa2
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

This comment block says the default algorithm is ESDSA, while the
code obviously sets the default to RSA:

  ifeq (${MBEDTLS_KEY_ALG},)
      MBEDTLS_KEY_ALG            :=      rsa
  endif

The git log of commit 7d37aa17

 ("TBB: add mbedTLS authentication
related libraries") states available options are:

  * 'rsa' (for RSA-2048) (default option)
  * 'ecdsa' (for ECDSA-SECP256R1)

So, my best guess is the comment block is wrong.

The mismatch between the code and the comment is confusing. Fix it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

This patch adds support for non-volatile counter authentication to
the Authentication Module. This method consists of matching the
counter values provided in the certificates with the ones stored
in the platform. If the value from the certificate is lower than
the platform, the boot process is aborted. This mechanism protects
the system against rollback.

The TBBR CoT has been updated to include this method as part of the
authentication process. Two counters are used: one for the trusted
world images and another for the non trusted world images.

** NEW PLATFORM APIs (mandatory when TBB is enabled) **

int plat_get_nv_ctr(void *cookie, unsigned int *nv_ctr);

    This API returns the non-volatile counter value stored
    in the platform. The cookie in the first argument may be
    used to select the counter in case the platform provides
    more than one (i.e. TBSA compliant platforms must provide
    trusted and non-trusted counters). This cookie is specified
    in the CoT.

int plat_set_nv_ctr(void *cookie, unsigned int nv_ctr);

    This API sets a new counter value. The cookie may be
    used to select the counter to be updated.

An implementation of these new APIs for ARM platforms is also
provided. The values are obtained from the Trusted Non-Volatile
Counters peripheral. The cookie is used to pass the extension OID.
This OID may be interpreted by the platform to know which counter
must return. On Juno, The trusted and non-trusted counter values
have been tied to 31 and 223, respectively, and cannot be modified.

** IMPORTANT **

THIS PATCH BREAKS THE BUILD WHEN TRUSTED_BOARD_BOOT IS ENABLED. THE
NEW PLATFORM APIs INTRODUCED IN THIS PATCH MUST BE IMPLEMENTED IN
ORDER TO SUCCESSFULLY BUILD TF.

Change-Id: Ic943b76b25f2a37f490eaaab6d87b4a8b3cbc89a

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