Alternatively to the X9.62 encoding of ecdsa signatures, which uses
ASN.1 and is already supported by the kernel, there's another common
encoding called P1363. It stores r and s as the concatenation of two
big endian, unsigned integers. The name originates from IEEE P1363.
Add a P1363 template in support of the forthcoming SPDM library
(Security Protocol and Data Model) for PCI device authentication.
P1363 is prescribed by SPDM 1.2.1 margin no 44:
"For ECDSA signatures, excluding SM2, in SPDM, the signature shall be
the concatenation of r and s. The size of r shall be the size of
the selected curve. Likewise, the size of s shall be the size of
the selected curve. See BaseAsymAlgo in NEGOTIATE_ALGORITHMS for
the size of r and s. The byte order for r and s shall be in big
endian order. When placing ECDSA signatures into an SPDM signature
field, r shall come first followed by s."
Link: https://www.dmtf.org/sites/default/files/standards/documents/DSP0274_1.2.1.pdf
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
software_key_query() returns the maximum signature and digest size for a
given key to user space. When it only supported RSA keys, calculating
those sizes was trivial as they were always equivalent to the key size.
However when ECDSA was added, the function grew somewhat complicated
calculations which take the ASN.1 encoding and curve into account.
This doesn't scale well and adjusting the calculations is easily
forgotten when adding support for new encodings or curves. In fact,
when NIST P521 support was recently added, the function was initially
not amended:
https://lore.kernel.org/all/b749d5ee-c3b8-4cbd-b252-7773e4536e07@linux.ibm.com/
Introduce a ->max_size() callback to struct sig_alg and take advantage
of it to move the signature size calculations to ecdsa-x962.c.
Introduce a ->digest_size() callback to struct sig_alg and move the
maximum ECDSA digest size to ecdsa.c. It is common across ecdsa-x962.c
and the upcoming ecdsa-p1363.c and thus inherited by both of them.
For all other algorithms, continue using the key size as maximum
signature and digest size.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_sig_maxsize() is a bit of a misnomer as it doesn't return the
maximum signature size, but rather the key size.
Rename it as well as all implementations of the ->max_size callback.
A subsequent commit introduces a crypto_sig_maxsize() function which
returns the actual maximum signature size.
While at it, change the return type of crypto_sig_keysize() from int to
unsigned int for consistency with crypto_akcipher_maxsize(). None of
the callers checks for a negative return value and an error condition
can always be indicated by returning zero.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Unlike the rsa driver, which separates signature decoding and
signature verification into two steps, the ecdsa driver does both in one.
This restricts users to the one signature format currently supported
(X9.62) and prevents addition of others such as P1363, which is needed
by the forthcoming SPDM library (Security Protocol and Data Model) for
PCI device authentication.
Per Herbert's suggestion, change ecdsa to use a "raw" signature encoding
and then implement X9.62 and P1363 as templates which convert their
respective encodings to the raw one. One may then specify
"x962(ecdsa-nist-XXX)" or "p1363(ecdsa-nist-XXX)" to pick the encoding.
The present commit moves X9.62 decoding to a template. A separate
commit is going to introduce another template for P1363 decoding.
The ecdsa driver internally represents a signature as two u64 arrays of
size ECC_MAX_BYTES. This appears to be the most natural choice for the
raw format as it can directly be used for verification without having to
further decode signature data or copy it around.
Repurpose all the existing test vectors for "x962(ecdsa-nist-XXX)" and
create a duplicate of them to test the raw encoding.
Link: https://lore.kernel.org/all/ZoHXyGwRzVvYkcTP@gondor.apana.org.au/
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When extracting a signature component r or s from an ASN.1-encoded
integer, ecdsa_get_signature_rs() subtracts the expected length
"bufsize" from the ASN.1 length "vlen" (both of unsigned type size_t)
and stores the result in "diff" (of signed type ssize_t).
This results in a signed integer overflow if vlen > SSIZE_MAX + bufsize.
The kernel is compiled with -fno-strict-overflow, which implies -fwrapv,
meaning signed integer overflow is not undefined behavior. And the
function does check for overflow:
if (-diff >= bufsize)
return -EINVAL;
So the code is fine in principle but not very obvious. In the future it
might trigger a false-positive with CONFIG_UBSAN_SIGNED_WRAP=y.
Avoid by comparing the two unsigned variables directly and erroring out
if "vlen" is too large.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
A sig_alg backend has just been introduced with the intent of moving all
asymmetric sign/verify algorithms to it one by one.
Migrate ecdsa.c to the new backend.
One benefit of the new API is the use of kernel buffers instead of
sglists, which avoids the overhead of copying signature and digest
sglists back into kernel buffers. ecdsa.c is thus simplified quite
a bit.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since ecc_digits_from_bytes will provide zeros when an insufficient number
of bytes are passed in the input byte array, use it to convert the r and s
components of the signature to digits directly from the input byte
array. This avoids going through an intermediate byte array that has the
first few bytes filled with zeros.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since ecc_digits_from_bytes will provide zeros when an insufficient number
of bytes are passed in the input byte array, use it to create the hash
digits directly from the input byte array. This avoids going through an
intermediate byte array (rawhash) that has the first few bytes filled with
zeros.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Public key blob is not just x and y concatenated. It follows RFC5480
section 2.2. Address this by re-documenting the function with the
correct description of the format.
Link: https://datatracker.ietf.org/doc/html/rfc5480
Fixes: 4e6602916b ("crypto: ecdsa - Add support for ECDSA signature verification")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Register NIST P521 as an akcipher and extend the testmgr with
NIST P521-specific test vectors.
Add a module alias so the module gets automatically loaded by the crypto
subsystem when the curve is needed.
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In cases where 'keylen' was referring to the size of the buffer used by
a curve's digits, it does not reflect the purpose of the variable anymore
once NIST P521 is used. What it refers to then is the size of the buffer,
which may be a few bytes larger than the size a coordinate of a key.
Therefore, rename keylen to bufsize where appropriate.
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Replace the usage of ndigits with nbits where precise space calculations
are needed, such as in ecdsa_max_size where the length of a coordinate is
determined.
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
res.x has been calculated by ecc_point_mult_shamir, which uses
'mod curve_prime' on res.x and therefore p > res.x with 'p' being the
curve_prime. Further, it is true that for the NIST curves p > n with 'n'
being the 'curve_order' and therefore the following may be true as well:
p > res.x >= n.
If res.x >= n then res.x mod n can be calculated by iteratively sub-
tracting n from res.x until res.x < n. For NIST P192/256/384 this can be
done in a single subtraction. This can also be done in a single
subtraction for NIST P521.
The mathematical reason why a single subtraction is sufficient is due to
the values of 'p' and 'n' of the NIST curves where the following holds
true:
note: max(res.x) = p - 1
max(res.x) - n < n
p - 1 - n < n
p - 1 < 2n => holds true for the NIST curves
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In preparation for support of NIST P521, adjust the basic tests on the
length of the provided key parameters to only ensure that the length of the
x plus y coordinates parameter array is not an odd number and that each
coordinate fits into an array of 'ndigits' digits. Mathematical tests on
the key's parameters are then done in ecc_is_pubkey_valid_full rejecting
invalid keys.
The change is necessary since NIST P521 keys do not have keys with
coordinates that each require 'full' digits (= all bits in u64 used).
NIST P521 only requires 2 bytes (9 bits) in the most significant digit
unlike NIST P192/256/384 that each require multiple 'full' digits.
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
For NIST P192/256/384 the public key's x and y parameters could be copied
directly from a given array since both parameters filled 'ndigits' of
digits (a 'digit' is a u64). For support of NIST P521 the key parameters
need to have leading zeros prepended to the most significant digit since
only 2 bytes of the most significant digit are provided.
Therefore, implement ecc_digits_from_bytes to convert a byte array into an
array of digits and use this function in ecdsa_set_pub_key where an input
byte array needs to be converted into digits.
Suggested-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add module alias with the algorithm cra_name similar to what we have for
RSA-related and other algorithms.
The kernel attempts to modprobe asymmetric algorithms using the names
"crypto-$cra_name" and "crypto-$cra_name-all." However, since these
aliases are currently missing, the modules are not loaded. For instance,
when using the `add_key` function, the hash algorithm is typically
loaded automatically, but the asymmetric algorithm is not.
Steps to test:
1. Create certificate
openssl req -x509 -sha256 -newkey ec \
-pkeyopt "ec_paramgen_curve:secp384r1" -keyout key.pem -days 365 \
-subj '/CN=test' -nodes -outform der -out nist-p384.der
2. Optionally, trace module requests with: trace-cmd stream -e module &
3. Trigger add_key call for the cert:
# keyctl padd asymmetric "" @u < nist-p384.der
641069229
# lsmod | head -2
Module Size Used by
ecdsa_generic 16384 0
Fixes: c12d448ba9 ("crypto: ecdsa - Register NIST P384 and extend test suite")
Cc: stable@vger.kernel.org
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Vitaly Chikunov <vt@altlinux.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Move ecc.h header file to 'include/crypto/internal' so that it can be
easily imported from everywhere in the kernel tree.
This change is done to allow crypto device drivers to re-use the symbols
exported by 'crypto/ecc.c', thus avoiding code duplication.
Signed-off-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Register NIST P384 as an akcipher and extend the testmgr with
NIST P384-specific test vectors.
Summary of changes:
* crypto/ecdsa.c
- add ecdsa_nist_p384_init_tfm
- register and unregister P384 tfm
* crypto/testmgr.c
- add test vector for P384 on vector of tests
* crypto/testmgr.h
- add test vector params for P384(sha1, sha224, sha256, sha384
and sha512)
Signed-off-by: Saulo Alessandre <saulo.alessandre@tse.jus.br>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add support for parsing the parameters of a NIST P256 or NIST P192 key.
Enable signature verification using these keys. The new module is
enabled with CONFIG_ECDSA:
Elliptic Curve Digital Signature Algorithm (NIST P192, P256 etc.)
is A NIST cryptographic standard algorithm. Only signature verification
is implemented.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
