Lukas Wunner 1e562deace crypto: rsassa-pkcs1 - Migrate to sig_alg backend ... A sig_alg backend has just been introduced with the intent of moving all asymmetric sign/verify algorithms to it one by one. Migrate the sign/verify operations from rsa-pkcs1pad.c to a separate rsassa-pkcs1.c which uses the new backend. Consequently there are now two templates which build on the "rsa" akcipher_alg: * The existing "pkcs1pad" template, which is instantiated as an akcipher_instance and retains the encrypt/decrypt operations of RSAES-PKCS1-v1_5 (RFC 8017 sec 7.2). * The new "pkcs1" template, which is instantiated as a sig_instance and contains the sign/verify operations of RSASSA-PKCS1-v1_5 (RFC 8017 sec 8.2). In a separate step, rsa-pkcs1pad.c could optionally be renamed to rsaes-pkcs1.c for clarity. Additional "oaep" and "pss" templates could be added for RSAES-OAEP and RSASSA-PSS. Note that it's currently allowed to allocate a "pkcs1pad(rsa)" transform without specifying a hash algorithm. That makes sense if the transform is only used for encrypt/decrypt and continues to be supported. But for sign/verify, such transforms previously did not insert the Full Hash Prefix into the padding. The resulting message encoding was incompliant with EMSA-PKCS1-v1_5 (RFC 8017 sec 9.2) and therefore nonsensical. From here on in, it is no longer allowed to allocate a transform without specifying a hash algorithm if the transform is used for sign/verify operations. This simplifies the code because the insertion of the Full Hash Prefix is no longer optional, so various "if (digest_info)" clauses can be removed. There has been a previous attempt to forbid transform allocation without specifying a hash algorithm, namely by commit c0d20d22e0 ("crypto: rsa-pkcs1pad - Require hash to be present"). It had to be rolled back with commit b3a8c8a5eb ("crypto: rsa-pkcs1pad: Allow hash to be optional [ver #2]"), presumably because it broke allocation of a transform which was solely used for encrypt/decrypt, not sign/verify. Avoid such breakage by allowing transform allocation for encrypt/decrypt with and without specifying a hash algorithm (and simply ignoring the hash algorithm in the former case). So again, specifying a hash algorithm is now mandatory for sign/verify, but optional and ignored for encrypt/decrypt. The new sig_alg API uses kernel buffers instead of sglists, which avoids the overhead of copying signature and digest from sglists back into kernel buffers. rsassa-pkcs1.c is thus simplified quite a bit. sig_alg is always synchronous, whereas the underlying "rsa" akcipher_alg may be asynchronous. So await the result of the akcipher_alg, similar to crypto_akcipher_sync_{en,de}crypt(). As part of the migration, rename "rsa_digest_info" to "hash_prefix" to adhere to the spec language in RFC 9580. Otherwise keep the code unmodified wherever possible to ease reviewing and bisecting. Leave several simplification and hardening opportunities to separate commits. rsassa-pkcs1.c uses modern __free() syntax for allocation of buffers which need to be freed by kfree_sensitive(), hence a DEFINE_FREE() clause for kfree_sensitive() is introduced herein as a byproduct. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>		2024-10-05 13:22:04 +08:00
..
evm	lsm: Refactor return value of LSM hook inode_copy_up_xattr	2024-07-31 14:47:09 -04:00
ima	crypto: rsassa-pkcs1 - Migrate to sig_alg backend	2024-10-05 13:22:04 +08:00
platform_certs	Hi,	2023-08-29 08:05:18 -07:00
digsig_asymmetric.c	crypto: sm2 - Remove sm2 algorithm	2024-06-07 19:46:39 +08:00
digsig.c	integrity: eliminate unnecessary "Problem loading X.509 certificate" msg	2024-02-16 08:04:17 -05:00
iint.c	integrity: Remove LSM	2024-02-15 23:43:48 -05:00
integrity_audit.c	integrity: check the return value of audit_log_start()	2022-02-02 11:44:23 -05:00
integrity.h	integrity: Avoid -Wflex-array-member-not-at-end warnings	2024-04-08 07:55:48 -04:00
Kconfig	integrity-v6.7	2023-11-02 06:53:22 -10:00
Makefile	ima: Move to LSM infrastructure	2024-02-15 23:43:46 -05:00