KEYS: Provide keyctls to drive the new key type ops for asymmetric keys

Provide five keyctl functions that permit userspace to make use of the new
key type ops for accessing and driving asymmetric keys.

 (*) Query an asymmetric key.

	long keyctl(KEYCTL_PKEY_QUERY,
		    key_serial_t key, unsigned long reserved,
		    struct keyctl_pkey_query *info);

     Get information about an asymmetric key.  The information is returned
     in the keyctl_pkey_query struct:

	__u32	supported_ops;

     A bit mask of flags indicating which ops are supported.  This is
     constructed from a bitwise-OR of:

	KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}

	__u32	key_size;

     The size in bits of the key.

	__u16	max_data_size;
	__u16	max_sig_size;
	__u16	max_enc_size;
	__u16	max_dec_size;

     The maximum sizes in bytes of a blob of data to be signed, a signature
     blob, a blob to be encrypted and a blob to be decrypted.

     reserved must be set to 0.  This is intended for future use to hand
     over one or more passphrases needed unlock a key.

     If successful, 0 is returned.  If the key is not an asymmetric key,
     EOPNOTSUPP is returned.


 (*) Encrypt, decrypt, sign or verify a blob using an asymmetric key.

	long keyctl(KEYCTL_PKEY_ENCRYPT,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_DECRYPT,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_SIGN,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    void *out);

	long keyctl(KEYCTL_PKEY_VERIFY,
		    const struct keyctl_pkey_params *params,
		    const char *info,
		    const void *in,
		    const void *in2);

     Use an asymmetric key to perform a public-key cryptographic operation
     a blob of data.

     The parameter block pointed to by params contains a number of integer
     values:

	__s32		key_id;
	__u32		in_len;
	__u32		out_len;
	__u32		in2_len;

     For a given operation, the in and out buffers are used as follows:

	Operation ID		in,in_len	out,out_len	in2,in2_len
	=======================	===============	===============	===========
	KEYCTL_PKEY_ENCRYPT	Raw data	Encrypted data	-
	KEYCTL_PKEY_DECRYPT	Encrypted data	Raw data	-
	KEYCTL_PKEY_SIGN	Raw data	Signature	-
	KEYCTL_PKEY_VERIFY	Raw data	-		Signature

     info is a string of key=value pairs that supply supplementary
     information.

     The __spare space in the parameter block must be set to 0.  This is
     intended, amongst other things, to allow the passing of passphrases
     required to unlock a key.

     If successful, encrypt, decrypt and sign all return the amount of data
     written into the output buffer.  Verification returns 0 on success.

Signed-off-by: David Howells <dhowells@redhat.com>

5 files changed, 405 insertions, 0 deletions

diff --git a/security/keys/Makefile b/security/keys/Makefile
index 1fd4a16e6daf..981be73e938f 100644
--- a/security/keys/Makefile
+++ b/security/keys/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_SYSCTL) += sysctl.o
 obj-$(CONFIG_PERSISTENT_KEYRINGS) += persistent.o
 obj-$(CONFIG_KEY_DH_OPERATIONS) += dh.o
+obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += keyctl_pkey.o
 
 #
 # Key types
diff --git a/security/keys/compat.c b/security/keys/compat.c
index 36c80bf5b89c..519010ae3f4f 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -136,6 +136,24 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option,
 		return keyctl_dh_compute(compat_ptr(arg2), compat_ptr(arg3),
 					 arg4, compat_ptr(arg5));
 
+	case KEYCTL_PKEY_QUERY:
+		if (arg3 != 0)
+			return -EINVAL;
+		return keyctl_pkey_query(arg2,
+					 compat_ptr(arg4),
+					 compat_ptr(arg5));
+
+	case KEYCTL_PKEY_ENCRYPT:
+	case KEYCTL_PKEY_DECRYPT:
+	case KEYCTL_PKEY_SIGN:
+		return keyctl_pkey_e_d_s(option,
+					 compat_ptr(arg2), compat_ptr(arg3),
+					 compat_ptr(arg4), compat_ptr(arg5));
+
+	case KEYCTL_PKEY_VERIFY:
+		return keyctl_pkey_verify(compat_ptr(arg2), compat_ptr(arg3),
+					  compat_ptr(arg4), compat_ptr(arg5));
+
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index a705a7d92ad7..7c34fab5be70 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -270,6 +270,45 @@ static inline long keyctl_dh_compute(struct keyctl_dh_params __user *params,
 }
 #endif
 
+#ifdef CONFIG_ASYMMETRIC_KEY_TYPE
+extern long keyctl_pkey_query(key_serial_t,
+			      const char __user *,
+			      struct keyctl_pkey_query __user *);
+
+extern long keyctl_pkey_verify(const struct keyctl_pkey_params __user *,
+			       const char __user *,
+			       const void __user *, const void __user *);
+
+extern long keyctl_pkey_e_d_s(int,
+			      const struct keyctl_pkey_params __user *,
+			      const char __user *,
+			      const void __user *, void __user *);
+#else
+static inline long keyctl_pkey_query(key_serial_t id,
+				     const char __user *_info,
+				     struct keyctl_pkey_query __user *_res)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline long keyctl_pkey_verify(const struct keyctl_pkey_params __user *params,
+				      const char __user *_info,
+				      const void __user *_in,
+				      const void __user *_in2)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline long keyctl_pkey_e_d_s(int op,
+				     const struct keyctl_pkey_params __user *params,
+				     const char __user *_info,
+				     const void __user *_in,
+				     void __user *_out)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
 /*
  * Debugging key validation
  */
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index d580ad06b792..1fb1ac472341 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1691,6 +1691,30 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
 					 (char __user *) arg3, (size_t) arg4,
 					 (void __user *) arg5);
 
+	case KEYCTL_PKEY_QUERY:
+		if (arg3 != 0)
+			return -EINVAL;
+		return keyctl_pkey_query((key_serial_t)arg2,
+					 (const char __user *)arg4,
+					 (struct keyctl_pkey_query *)arg5);
+
+	case KEYCTL_PKEY_ENCRYPT:
+	case KEYCTL_PKEY_DECRYPT:
+	case KEYCTL_PKEY_SIGN:
+		return keyctl_pkey_e_d_s(
+			option,
+			(const struct keyctl_pkey_params __user *)arg2,
+			(const char __user *)arg3,
+			(const void __user *)arg4,
+			(void __user *)arg5);
+
+	case KEYCTL_PKEY_VERIFY:
+		return keyctl_pkey_verify(
+			(const struct keyctl_pkey_params __user *)arg2,
+			(const char __user *)arg3,
+			(const void __user *)arg4,
+			(const void __user *)arg5);
+
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/security/keys/keyctl_pkey.c b/security/keys/keyctl_pkey.c
new file mode 100644
index 000000000000..783978842f13
--- /dev/null
+++ b/security/keys/keyctl_pkey.c
@@ -0,0 +1,323 @@
+/* Public-key operation keyctls
+ *
+ * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/key.h>
+#include <linux/keyctl.h>
+#include <linux/parser.h>
+#include <linux/uaccess.h>
+#include <keys/user-type.h>
+#include "internal.h"
+
+static void keyctl_pkey_params_free(struct kernel_pkey_params *params)
+{
+	kfree(params->info);
+	key_put(params->key);
+}
+
+enum {
+	Opt_err = -1,
+	Opt_enc,		/* "enc=<encoding>" eg. "enc=oaep" */
+	Opt_hash,		/* "hash=<digest-name>" eg. "hash=sha1" */
+};
+
+static const match_table_t param_keys = {
+	{ Opt_enc,	"enc=%s" },
+	{ Opt_hash,	"hash=%s" },
+	{ Opt_err,	NULL }
+};
+
+/*
+ * Parse the information string which consists of key=val pairs.
+ */
+static int keyctl_pkey_params_parse(struct kernel_pkey_params *params)
+{
+	unsigned long token_mask = 0;
+	substring_t args[MAX_OPT_ARGS];
+	char *c = params->info, *p, *q;
+	int token;
+
+	while ((p = strsep(&c, " \t"))) {
+		if (*p == '\0' || *p == ' ' || *p == '\t')
+			continue;
+		token = match_token(p, param_keys, args);
+		if (__test_and_set_bit(token, &token_mask))
+			return -EINVAL;
+		q = args[0].from;
+		if (!q[0])
+			return -EINVAL;
+
+		switch (token) {
+		case Opt_enc:
+			params->encoding = q;
+			break;
+
+		case Opt_hash:
+			params->hash_algo = q;
+			break;
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Interpret parameters.  Callers must always call the free function
+ * on params, even if an error is returned.
+ */
+static int keyctl_pkey_params_get(key_serial_t id,
+				  const char __user *_info,
+				  struct kernel_pkey_params *params)
+{
+	key_ref_t key_ref;
+	void *p;
+	int ret;
+
+	memset(params, 0, sizeof(*params));
+	params->encoding = "raw";
+
+	p = strndup_user(_info, PAGE_SIZE);
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+	params->info = p;
+
+	ret = keyctl_pkey_params_parse(params);
+	if (ret < 0)
+		return ret;
+
+	key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
+	if (IS_ERR(key_ref))
+		return PTR_ERR(key_ref);
+	params->key = key_ref_to_ptr(key_ref);
+
+	if (!params->key->type->asym_query)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+/*
+ * Get parameters from userspace.  Callers must always call the free function
+ * on params, even if an error is returned.
+ */
+static int keyctl_pkey_params_get_2(const struct keyctl_pkey_params __user *_params,
+				    const char __user *_info,
+				    int op,
+				    struct kernel_pkey_params *params)
+{
+	struct keyctl_pkey_params uparams;
+	struct kernel_pkey_query info;
+	int ret;
+
+	memset(params, 0, sizeof(*params));
+	params->encoding = "raw";
+
+	if (copy_from_user(&uparams, _params, sizeof(uparams)) != 0)
+		return -EFAULT;
+
+	ret = keyctl_pkey_params_get(uparams.key_id, _info, params);
+	if (ret < 0)
+		return ret;
+
+	ret = params->key->type->asym_query(params, &info);
+	if (ret < 0)
+		return ret;
+
+	switch (op) {
+	case KEYCTL_PKEY_ENCRYPT:
+	case KEYCTL_PKEY_DECRYPT:
+		if (uparams.in_len  > info.max_enc_size ||
+		    uparams.out_len > info.max_dec_size)
+			return -EINVAL;
+		break;
+	case KEYCTL_PKEY_SIGN:
+	case KEYCTL_PKEY_VERIFY:
+		if (uparams.in_len  > info.max_sig_size ||
+		    uparams.out_len > info.max_data_size)
+			return -EINVAL;
+		break;
+	default:
+		BUG();
+	}
+
+	params->in_len  = uparams.in_len;
+	params->out_len = uparams.out_len;
+	return 0;
+}
+
+/*
+ * Query information about an asymmetric key.
+ */
+long keyctl_pkey_query(key_serial_t id,
+		       const char __user *_info,
+		       struct keyctl_pkey_query __user *_res)
+{
+	struct kernel_pkey_params params;
+	struct kernel_pkey_query res;
+	long ret;
+
+	memset(&params, 0, sizeof(params));
+
+	ret = keyctl_pkey_params_get(id, _info, &params);
+	if (ret < 0)
+		goto error;
+
+	ret = params.key->type->asym_query(&params, &res);
+	if (ret < 0)
+		goto error;
+
+	ret = -EFAULT;
+	if (copy_to_user(_res, &res, sizeof(res)) == 0 &&
+	    clear_user(_res->__spare, sizeof(_res->__spare)) == 0)
+		ret = 0;
+
+error:
+	keyctl_pkey_params_free(&params);
+	return ret;
+}
+
+/*
+ * Encrypt/decrypt/sign
+ *
+ * Encrypt data, decrypt data or sign data using a public key.
+ *
+ * _info is a string of supplementary information in key=val format.  For
+ * instance, it might contain:
+ *
+ *	"enc=pkcs1 hash=sha256"
+ *
+ * where enc= specifies the encoding and hash= selects the OID to go in that
+ * particular encoding if required.  If enc= isn't supplied, it's assumed that
+ * the caller is supplying raw values.
+ *
+ * If successful, the amount of data written into the output buffer is
+ * returned.
+ */
+long keyctl_pkey_e_d_s(int op,
+		       const struct keyctl_pkey_params __user *_params,
+		       const char __user *_info,
+		       const void __user *_in,
+		       void __user *_out)
+{
+	struct kernel_pkey_params params;
+	void *in, *out;
+	long ret;
+
+	ret = keyctl_pkey_params_get_2(_params, _info, op, &params);
+	if (ret < 0)
+		goto error_params;
+
+	ret = -EOPNOTSUPP;
+	if (!params.key->type->asym_eds_op)
+		goto error_params;
+
+	switch (op) {
+	case KEYCTL_PKEY_ENCRYPT:
+		params.op = kernel_pkey_encrypt;
+		break;
+	case KEYCTL_PKEY_DECRYPT:
+		params.op = kernel_pkey_decrypt;
+		break;
+	case KEYCTL_PKEY_SIGN:
+		params.op = kernel_pkey_sign;
+		break;
+	default:
+		BUG();
+	}
+
+	in = memdup_user(_in, params.in_len);
+	if (IS_ERR(in)) {
+		ret = PTR_ERR(in);
+		goto error_params;
+	}
+
+	ret = -ENOMEM;
+	out = kmalloc(params.out_len, GFP_KERNEL);
+	if (!out)
+		goto error_in;
+
+	ret = params.key->type->asym_eds_op(&params, in, out);
+	if (ret < 0)
+		goto error_out;
+
+	if (copy_to_user(_out, out, ret) != 0)
+		ret = -EFAULT;
+
+error_out:
+	kfree(out);
+error_in:
+	kfree(in);
+error_params:
+	keyctl_pkey_params_free(&params);
+	return ret;
+}
+
+/*
+ * Verify a signature.
+ *
+ * Verify a public key signature using the given key, or if not given, search
+ * for a matching key.
+ *
+ * _info is a string of supplementary information in key=val format.  For
+ * instance, it might contain:
+ *
+ *	"enc=pkcs1 hash=sha256"
+ *
+ * where enc= specifies the signature blob encoding and hash= selects the OID
+ * to go in that particular encoding.  If enc= isn't supplied, it's assumed
+ * that the caller is supplying raw values.
+ *
+ * If successful, 0 is returned.
+ */
+long keyctl_pkey_verify(const struct keyctl_pkey_params __user *_params,
+			const char __user *_info,
+			const void __user *_in,
+			const void __user *_in2)
+{
+	struct kernel_pkey_params params;
+	void *in, *in2;
+	long ret;
+
+	ret = keyctl_pkey_params_get_2(_params, _info, KEYCTL_PKEY_VERIFY,
+				       &params);
+	if (ret < 0)
+		goto error_params;
+
+	ret = -EOPNOTSUPP;
+	if (!params.key->type->asym_verify_signature)
+		goto error_params;
+
+	in = memdup_user(_in, params.in_len);
+	if (IS_ERR(in)) {
+		ret = PTR_ERR(in);
+		goto error_params;
+	}
+
+	in2 = memdup_user(_in2, params.in2_len);
+	if (IS_ERR(in2)) {
+		ret = PTR_ERR(in2);
+		goto error_in;
+	}
+
+	params.op = kernel_pkey_verify;
+	ret = params.key->type->asym_verify_signature(&params, in, in2);
+
+	kfree(in2);
+error_in:
+	kfree(in);
+error_params:
+	keyctl_pkey_params_free(&params);
+	return ret;
+}