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2024-10-05crypto: ecdsa - Move X9.62 signature size calculation into templateLukas Wunner1-0/+38
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>
2024-10-05crypto: sig - Rename crypto_sig_maxsize() to crypto_sig_keysize()Lukas Wunner1-7/+7
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>
2024-10-05crypto: sig - Move crypto_sig_*() API calls to include fileLukas Wunner1-11/+36
The crypto_sig_*() API calls lived in sig.c so far because they needed access to struct crypto_sig_type: This was necessary to differentiate between signature algorithms that had already been migrated from crypto_akcipher to crypto_sig and those that hadn't yet. Now that all algorithms have been migrated, the API calls can become static inlines in <crypto/sig.h> to mimic what <crypto/akcipher.h> is doing. Signed-off-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2024-10-05crypto: sig - Introduce sig_alg backendLukas Wunner1-0/+61
Commit 6cb8815f41a9 ("crypto: sig - Add interface for sign/verify") began a transition of asymmetric sign/verify operations from crypto_akcipher to a new crypto_sig frontend. Internally, the crypto_sig frontend still uses akcipher_alg as backend, however: "The link between sig and akcipher is meant to be temporary. The plan is to create a new low-level API for sig and then migrate the signature code over to that from akcipher." https://lore.kernel.org/r/ZrG6w9wsb-iiLZIF@gondor.apana.org.au/ "having a separate alg for sig is definitely where we want to be since there is very little that the two types actually share." https://lore.kernel.org/r/ZrHlpz4qnre0zWJO@gondor.apana.org.au/ Take the next step of that migration and augment the crypto_sig frontend with a sig_alg backend to which all algorithms can be moved. During the migration, there will briefly be signature algorithms that are still based on crypto_akcipher, whilst others are already based on crypto_sig. Allow for that by building a fork into crypto_sig_*() API calls (i.e. crypto_sig_maxsize() and friends) such that one of the two backends is selected based on the transform's cra_type. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-05crypto: sig - fix kernel-doc typoRandy Dunlap1-1/+1
Correct typo of "destination". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-crypto@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-06-23crypto: sig - Add interface for sign/verifyHerbert Xu1-0/+140
Split out the sign/verify functionality from the existing akcipher interface. Most algorithms in akcipher either support encryption and decryption, or signing and verify. Only one supports both. As a signature algorithm may not support encryption at all, these two should be spearated. For now sig is simply a wrapper around akcipher as all algorithms remain unchanged. This is a first step and allows users to start allocating sig instead of akcipher. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>