[PATCH v2 18/18] keyctl_pkey: Add pkey parameters slen and mgfhash for PSS

[Varad Gautam]

keyctl pkey_* operations accept enc and hash parameters at present.
RSASSA-PSS signatures also require passing in the signature salt
length and the mgf hash function.

Add parameters:
- 'slen' to feed in salt length of a PSS signature.
- 'mgfhash' to feed in the hash function used for MGF.

Signed-off-by: Varad Gautam <varad.gau...@suse.com>
CC: Jarkko Sakkinen <jar...@kernel.org>
---
v2: Accept 'mgfhash' as a parameter. v1 assumed this to be the same
  as the digest hash.

 crypto/asymmetric_keys/asymmetric_type.c |  2 ++
 include/linux/keyctl.h                   |  2 ++
 security/keys/keyctl_pkey.c              | 13 +++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/crypto/asymmetric_keys/asymmetric_type.c 
b/crypto/asymmetric_keys/asymmetric_type.c
index ad8af3d70ac04..72c1bf964826f 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -571,6 +571,8 @@ static int asymmetric_key_verify_signature(struct 
kernel_pkey_params *params,
                .hash_algo      = params->hash_algo,
                .digest         = (void *)in,
                .s              = (void *)in2,
+               .salt_length    = params->slen,
+               .mgf_hash_algo  = params->mgf_hash_algo,
        };
 
        return verify_signature(params->key, &sig);
diff --git a/include/linux/keyctl.h b/include/linux/keyctl.h
index 5b79847207ef2..753d004d76ece 100644
--- a/include/linux/keyctl.h
+++ b/include/linux/keyctl.h
@@ -37,6 +37,8 @@ struct kernel_pkey_params {
                __u32   in2_len;        /* 2nd input data size (verify) */
        };
        enum kernel_pkey_operation op : 8;
+       __u32           slen;
+       const char      *mgf_hash_algo;
 };
 
 #endif /* __LINUX_KEYCTL_H */
diff --git a/security/keys/keyctl_pkey.c b/security/keys/keyctl_pkey.c
index 5de0d599a2748..ae3a81c726322 100644
--- a/security/keys/keyctl_pkey.c
+++ b/security/keys/keyctl_pkey.c
@@ -24,11 +24,15 @@ enum {
        Opt_err,
        Opt_enc,                /* "enc=<encoding>" eg. "enc=oaep" */
        Opt_hash,               /* "hash=<digest-name>" eg. "hash=sha1" */
+       Opt_slen,               /* "slen=<salt-length>" eg. "slen=32" */
+       Opt_mgfhash,            /* "mgfhash=<digest-name>" eg. "mgfhash=sha1" */
 };
 
 static const match_table_t param_keys = {
        { Opt_enc,      "enc=%s" },
        { Opt_hash,     "hash=%s" },
+       { Opt_slen,     "slen=%u" },
+       { Opt_mgfhash,  "mgfhash=%s" },
        { Opt_err,      NULL }
 };
 
@@ -63,6 +67,15 @@ static int keyctl_pkey_params_parse(struct 
kernel_pkey_params *params)
                        params->hash_algo = q;
                        break;
 
+               case Opt_slen:
+                       if (kstrtouint(q, 0, &params->slen))
+                               return -EINVAL;
+                       break;
+
+               case Opt_mgfhash:
+                       params->mgf_hash_algo = q;
+                       break;
+
                default:
                        return -EINVAL;
                }
-- 
2.30.2