Add two functions mbedtls_dhm_get_len() and mbedtls_dhm_get_bitlen() to
query the length of the modulus in bytes or bits.
Remove the len field: the cost of calling mbedtls_dhm_get_len() each time
it's needed is negligible, and this improves the abstraction of the DHM
module.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
When MBEDTLS_RSA_ALT is defined, mbedtls_rsa_context does not necessarily
have fields called N and E of type mbedtls_mpi. Don't emit pk_debug
information with MBEDTLS_RSA_ALT. This is not ideal but at least the
library compiles.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Use headers defining dummy context types.
The test does not pass yet. I plan to fix this in subsequent commits.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The new method `Config.change_matching` and the new command-line
commands `set-all` and `unset-all` change a batch of existing boolean
settings to the desired state (active or inactive).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Follow-up to "Create xxx_alt.h headers for testing". The inclusion of
threading_alt.h in include/mbedtls/threading.h does not follow the
same pattern as the others so it was missed by the script.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
These headers define the context types that alternative implementations must
provide. The context types are dummy types, suitable for building but not
meant to be usable by an implementation.
This is the output of the following script:
```
perl -0777 -ne '
m@^#if !defined\((MBEDTLS_\w+_ALT)\).*\n((?:.*\n)*?)#else.*\n#include "(.*_alt\.h)"\n#endif@m or next;
$symbol = $1; $content = $2; $header = $3;
$header_symbol = $header; $header_symbol =~ y/a-z./A-Z_/;
m@/\*[ *\n]*Copyright .*?\*/@s or die; $copyright = $&;
open OUT, ">tests/include/alt-dummy/$header" or die;
$content =~ s@//.*@@mg;
$content =~ s@/\*.*?\*/@@sg;
$content =~ s@\{.*?\}@{\n int dummy;\n}@sg;
$content =~ s@ +$@@mg;
$content =~ s@\n{3,}@\n\n@g; $content =~ s@\A\n+@@; $content =~ s@\n*\Z@\n@;
print OUT "/* $header with dummy types for $symbol */\n$copyright\n\n#ifndef $header_symbol\n#define $header_symbol\n\n$content\n\n#endif /* $header */\n" or die;
close OUT or die;
' include/mbedtls/*.h
```
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
MBEDTLS_ECP_MAX_BITS doesn't make sense as a configuration option: it
must not be smaller than the largest supported curve, and it's useless
to set it to a larger value. So unconditionally set it to the size of
the largest supported curve. Remove it from the build configuration.
Alternative implementations must no longer need define this macro.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
library/ecp_alt.h (declaring individual functions of the ECP module that can
be substituted, included when building the library with
MBEDTLS_ECP_INTERNAL_ALT enabled) clashes with ecp_alt.h (not provided,
declaring types of the ECP module when the whole implementation is
substituted, included when building the library with MBEDTLS_ECP_ALT enabled).
Depending on the search path during build, this can make MBEDTLS_ECP_ALT
unusable.
Rename library/ecp_alt.h to follow the naming convention of other alt headers:
MBEDTLS_XXX_ALT corresponds to xxx_alt.h.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Conflicts:
include/mbedtls/ssl.h
include/psa/crypto_struct.h
Conflicts fixed by using the code from development branch
and manually re-applying the MBEDTLS_PRIVATE wrapping.
Mbed OS now provides POSIX-like time functions, although not alarm() nor
signal(). It is possible to implement MBEDTLS_TIMING_ALT on Mbed OS, so
we should not artificially prevent this in check-config. Remove the the
check that prevents implementing MBEDTLS_TIMING_ALT on Mbed OS.
Note that this limitation originally was added in the following commit,
although there isn't much context around why the restriction was
imposed: 63e7ebaaa1 ("Add material for generating yotta module"). In
2015, Mbed OS was quite a different thing: no RTOS, no threads, just an
asynchronous event loop model. I'd suppose the asynchronous event loop
model made it difficult before to implement MBEDTLS_TIMING_C on Mbed OS,
but that is no longer the case.
Fixes#4633
Signed-off-by: Jaeden Amero <jaeden.amero@arm.com>
Removing reference to RFC 7748 as it is more confusing than helpful. (It
decodes the scalars after masking which is not part of the encoding we
want to specify. Also, it has the explanation what it means by little
endian in a preceding section that is not trivial to find.)
We also explicitly specify constraint on leading zeroes.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The expression "the masking is omitted" assumes familiarity with
Montgomery curve private key format and even then can be confusing and
ambiguous or confusing.
Describe directly what format we mean and add some more background
information and reference to the standard as well.
Signed-off-by: Janos Follath <janos.follath@arm.com>
4-space indent is only guaranteed to result in a code block if there's a
blank line just before (details vary depending on the markdown
implementation, and doxygen isn't exactly markdown anyway). In a bullet
list, you need 8 spaces since the list itself is a nested construct
which takes a 4-space indent (even though you don't have to indent
continuation lines inside a bullet point by 4 spaces, 1 is enough).
Using \code...\encode which is rendering as intended.
Signed-off-by: Janos Follath <janos.follath@arm.com>
This level of detail can be confusing and could require even more detail
to clear it up. Simplifying it instead in alignment wiht the
documentation of existing setup functions.
Signed-off-by: Janos Follath <janos.follath@arm.com>
This reverts commit 03a5fd7780026b2ca0b4728352ded930f5a7cff9.
We're already calling the output of a PAKE a "shared secret". The
password is a shared secret (for PAKE where the verifier knows a
password-equivalent secret), but calling it "shared secret" or even just
"secret" would be confusing.
Signed-off-by: Janos Follath <janos.follath@arm.com>
Technically this function takes a low entropy secret as an input which
might or might not be the password. Using the term "secret" in the
function name is less misleading.
Signed-off-by: Janos Follath <janos.follath@arm.com>
The password stretching (using slow and/or memory hard hashes) in PAKEs
usually serves two purposes:
- Defending against server compromise impersonation attacks. J-PAKE is an
augmented PAKE and as such, stores a password-equivalent and defending
against this class of attacks is out of scope.
- Preventing offline dictionary attacks. J-PAKE is proven to be zero
knowledge and leaks no information beyond the fact if the passwords
matched and offline dictionary attack is not possible.
In summary: J-PAKE does not benefit from pasword stretching and is
unlikely to be an input. This part of the API is not necessary at this
point and can be added later.
Signed-off-by: Janos Follath <janos.follath@arm.com>
We are not confident about the stability of the PAKE interface (it is
just a proposal, not part of the standard yet). So we should explicitly
document it as experimental, subject to change.
Signed-off-by: Janos Follath <janos.follath@arm.com>
At this point this is a proposed PAKE interface for the PSA Crypto API
and not part of the official standard. Place the interface in
crypto_extra.h to make this clear.
Signed-off-by: Janos Follath <janos.follath@arm.com>
