Add mbedtls_ssl_conf_enable_new_session_tickets() API
to be able to enable and disable the handling of TLS 1.3
NewSessionTicket messages.
The TLS 1.2 equivalent function is named
mbedtls_ssl_conf_session_tickets() thus the most
natural name would have been
mbedtls_ssl_conf_new_session_tickets() but it is
already used on server side thus rather
mbedtls_ssl_conf_enable_new_session_tickets().
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This reduces the workflows where psa_crypto_init is called when not
necessary: it won't be called when a dual-version server receives a 1.2-only
ClientHello.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
For backward compatibility with Mbed TLS <=3.5.x, applications must be able
to make a TLS connection with a peer that supports both TLS 1.2 and TLS 1.3,
regardless of whether they call psa_crypto_init(). Since Mbed TLS 3.6.0,
we enable TLS 1.3 in the default configuration, so we must take care of
calling psa_crypto_init() if needed. This is a change from TLS 1.3 in
previous versions, where enabling MBEDTLS_SSL_PROTO_TLS1_3 was a user
choice and could have additional requirement.
This commit makes the library call psa_crypto_init() when it needs PSA
crypto in a situation where the application might not have called it,
namely, when starting a TLS 1.3 connection.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
We are technically allowed to use all possible values of key slice index
that will fit into the bit width we have allocated, so allow all values.
Signed-off-by: David Horstmann <david.horstmann@arm.com>
The persistent key cache slice is the last slice (not the first as
previously stated). Update the numbering-related comments accordingly.
Signed-off-by: David Horstmann <david.horstmann@arm.com>
The new test hooks allow to check whether there was an unsafe call of an
optionally safe function in the codepath. For the sake of simplicity the
MBEDTLS_MPI_IS_* macros are reused for signalling safe/unsafe codepaths
here too.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The allocated size can be significantly larger than the actual size. In
the unsafe case we can use the actual size and gain some performance.
Signed-off-by: Janos Follath <janos.follath@arm.com>
It is easier to read if the parameter controlling constant timeness with
respect to a parameter is next to that parameter.
Signed-off-by: Janos Follath <janos.follath@arm.com>
In Thumb instructions, constant can be:
- any constant that can be produced by shifting an 8-bit value left by any
number of bits within a 32-bit word
- any constant of the form 0x00XY00XY
- any constant of the form 0xXY00XY00
- any constant of the form 0xXYXYXYXY.
Signed-off-by: Janos Follath <janos.follath@arm.com>
These macros are not part of any public or internal API, ideally they
would be defined in the source files. The reason to put them in
bignum_core.h to avoid duplication as macros for this purpose are
needed in both bignum.c and bignum_core.c.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The complexity of having functions whose security properties depend on a
runtime argument can be dangerous. Limit risk by isolating such code in
small functions with limited scope.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The complexity of having functions whose security properties depend on a
runtime argument can be dangerous. Limit misuse by making any such
functions local.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Reassure both humans and compilers that the places where we assign an
integer to a smaller type are safe.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add a practical way to fill the dynamic key store by artificially limiting
the slice length through a test hook.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When MBEDTLS_PSA_KEY_STORE_DYNAMIC is enabled, key slots are now organized in
multiple slices. The slices are allocated on demand, which allows the key
store to grow. The size of slices grows exponentially, which allows reaching
a large number of slots with a small (static) number of slices without too
much overhead.
Maintain a linked list of free slots in each slice. This way, allocating a
slot takes O(1) time unless a slice needs to be allocated.
In this commit, slices are only ever freed when deinitializing the key
store. This should be improved in the future to free empty slices.
To avoid growing the persistent key cache without control, the persistent
key cache has a fixed size (reusing MBEDTLS_PSA_KEY_SLOT_COUNT to avoid
creating yet another option).
When MBEDTLS_PSA_KEY_STORE_DYNAMIC is disabled. no semantic change and
minimal changes to the code.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Place some fields of psa_key_slot_t in a union, to prepare for a new field
in free slots that should not require extra memory.
For occupied slots, place only the registered_readers field in the union,
not other fields, to minimize textual changes. All fields could move to the
union except state (also needed in free slots) and attr (which must stay
first to reduce the code size, because it is accessed at many call sites).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Add some abstractions around code that traverses the key store, in
preparation for adding support for MBEDTLS_PSA_KEY_STORE_DYNAMIC.
No intended behavior change. The generated machine code should be
almost the same with an optimizing compiler (in principle, it could be the
same with sufficient constant folding and inlining, but in practice it will
likely be a few byes larger),
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Implement `psa_generate_key_custom()` and
`psa_key_derivation_output_key_custom()`. These functions replace
`psa_generate_key_ext()` and `psa_key_derivation_output_key_ext()`.
They have the same functionality, but a slightly different interface:
the `ext` functions use a structure with a flexible array member to pass
variable-length data, while the `custom` functions use a separate parameter.
Keep the `ext` functions for backward compatibility with Mbed TLS 3.6.0.
But make them a thin wrapper around the new `custom` functions.
Duplicate the test code and data. The test cases have to be duplicated
anyway, and the test functions are individually more readable this way.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Avoid compiler warning about size comparison (like in commit 7910cdd):
Clang builds fail, warning about comparing uint8_t to a size that may be >255.
Signed-off-by: Michael Schuster <michael@schuster.ms>
Fix interference between PSA volatile keys and built-in keys
when MBEDTLS_PSA_CRYPTO_BUILTIN_KEYS is enabled and
MBEDTLS_PSA_KEY_SLOT_COUNT is more than 4096. This overlap used to make it
possible that a volatile key would receive the identifier of a built-in key,
and is now caught by a static assertion.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
