lib: rsa: add documentation to padding_pss_verify to document limitations

padding_pss_verify only works with the default pss salt setting of -2
(length to be automatically determined based on the PSS block structure)
not -1 (salt length set to the maximum permissible value), which makes
verifications of signatures with that saltlen fail.

Until this gets implemented at least document this behaviour.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Heiko Stuebner 2020-06-18 16:23:26 +02:00 committed by Tom Rini
parent eda753be8a
commit 1a62c23ecf

View file

@ -194,6 +194,19 @@ out:
return ret;
}
/*
* padding_pss_verify() - verify the pss padding of a signature
*
* Only works with a rsa_pss_saltlen:-2 (default value) right now
* saltlen:-1 "set the salt length to the digest length" is currently
* not supported.
*
* @info: Specifies key and FIT information
* @msg: byte array of message, len equal to msg_len
* @msg_len: Message length
* @hash: Pointer to the expected hash
* @hash_len: Length of the hash
*/
int padding_pss_verify(struct image_sign_info *info,
uint8_t *msg, int msg_len,
const uint8_t *hash, int hash_len)