[PATCH 18/18] keyctl_pkey: Add pkey parameter slen to pass in PSS salt length

From: Varad Gautam
Date: Tue Mar 30 2021 - 16:36:52 EST


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

Add another parameter 'slen' to feed in salt length of a PSS
signature.

Signed-off-by: Varad Gautam <varad.gautam@xxxxxxxx>
---
crypto/asymmetric_keys/asymmetric_type.c | 1 +
include/linux/keyctl.h | 1 +
security/keys/keyctl_pkey.c | 6 ++++++
3 files changed, 8 insertions(+)

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index ad8af3d70ac0..eb2ef4a07f8e 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -571,6 +571,7 @@ 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,
};

return verify_signature(params->key, &sig);
diff --git a/include/linux/keyctl.h b/include/linux/keyctl.h
index 5b79847207ef..970c7bed3082 100644
--- a/include/linux/keyctl.h
+++ b/include/linux/keyctl.h
@@ -37,6 +37,7 @@ struct kernel_pkey_params {
__u32 in2_len; /* 2nd input data size (verify) */
};
enum kernel_pkey_operation op : 8;
+ __u32 slen;
};

#endif /* __LINUX_KEYCTL_H */
diff --git a/security/keys/keyctl_pkey.c b/security/keys/keyctl_pkey.c
index 5de0d599a274..b54a021e16b1 100644
--- a/security/keys/keyctl_pkey.c
+++ b/security/keys/keyctl_pkey.c
@@ -24,11 +24,13 @@ 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" */
};

static const match_table_t param_keys = {
{ Opt_enc, "enc=%s" },
{ Opt_hash, "hash=%s" },
+ { Opt_slen, "slen=%u" },
{ Opt_err, NULL }
};

@@ -63,6 +65,10 @@ 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;
default:
return -EINVAL;
}
--
2.30.2