From: David Howells Subject: [RFC PATCH 2/8] KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver 3] Date: Wed, 11 May 2016 15:22:08 +0100 Message-ID: <20160511142207.4743.40300.stgit@warthog.procyon.org.uk> References: <20160511142152.4743.14414.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, dwmw2@infradead.org To: mathew.j.martineau@linux.intel.com, tadeusz.struk@intel.com Return-path: In-Reply-To: <20160511142152.4743.14414.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org 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, key_serial_t password, 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 decypted. If the key needs to be unlocked with a password, a logon-type key that holds the password may be given as the password argument 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; __s32 password_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 If the key must be unlocked with a password before it can be used, password_id should point to a logon-type key that holds this. info is a string of key=value pairs that supply supplementary information. 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 --- Documentation/security/keys.txt | 111 +++++++++++++ include/uapi/linux/keyctl.h | 26 +++ security/keys/Makefile | 1 security/keys/compat.c | 15 ++ security/keys/internal.h | 39 +++++ security/keys/keyctl.c | 23 +++ security/keys/keyctl_pkey.c | 335 +++++++++++++++++++++++++++++++++++++++ 7 files changed, 550 insertions(+) create mode 100644 security/keys/keyctl_pkey.c diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt index ca72b70a24b9..01c2ae28a8c0 100644 --- a/Documentation/security/keys.txt +++ b/Documentation/security/keys.txt @@ -854,6 +854,117 @@ The keyctl syscall functions are: supported, error ENOKEY if the key could not be found, or error EACCES if the key is not readable by the caller. + + (*) Query an asymmetric key. + + long keyctl(KEYCTL_PKEY_QUERY, + key_serial_t key, key_serial_t password, + 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 decypted. + + If the key needs to be unlocked with a password, a logon-type key that + holds the password may be given as the password argument + + 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. For encryption and verification, the asymmetric key may + only need the public parts to be available, but for decryption and signing + the private parts are required also. + + The parameter block pointed to by params contains a number of integer + values: + + __s32 key_id; + __s32 password_id; + __u32 in_len; + __u32 out_len; + __u32 in2_len; + + key_id is the ID of the asymmetric key to be used. in_len and in2_len + indicate the amount of data in the in and in2 buffers and out_len + indicates the size of the out buffer as appropriate for the above + operations. + + 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 + + If the key must be unlocked with a password before it can be used, + password_id should point to a logon-type key that holds this. + + info is a string of key=value pairs that supply supplementary information. + These include: + + enc= The encoding of the encrypted/signature blob. This can + be "pkcs1" for RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5; + "pss" for "RSASSA-PSS"; "oaep" for "RSAES-OAEP". If + omitted or is "raw", the raw output of the encryption + function is specified. + + hash= If the data buffer contains the output of a hash + function and the encoding includes some indication of + which hash function was used, the hash function can be + specified with this, eg. "hash=sha256". + + If successful, encrypt, decrypt and sign all return the amount of data + written into the output buffer. Verification returns 0 on success. + + =============== KERNEL SERVICES =============== diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 8ac2c5fbc8fc..05f4f6ffbad2 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -60,6 +60,11 @@ #define KEYCTL_INVALIDATE 21 /* invalidate a key */ #define KEYCTL_GET_PERSISTENT 22 /* get a user's persistent keyring */ #define KEYCTL_DH_COMPUTE 23 /* Compute Diffie-Hellman values */ +#define KEYCTL_PKEY_QUERY 24 /* Query public key parameters */ +#define KEYCTL_PKEY_ENCRYPT 25 /* Encrypt a blob using a public key */ +#define KEYCTL_PKEY_DECRYPT 26 /* Decrypt a blob using a public key */ +#define KEYCTL_PKEY_SIGN 27 /* Create a public key signature */ +#define KEYCTL_PKEY_VERIFY 28 /* Verify a public key signature */ /* keyctl structures */ struct keyctl_dh_params { @@ -73,4 +78,25 @@ struct keyctl_dh_params { #define KEYCTL_SUPPORTS_SIGN 0x04 #define KEYCTL_SUPPORTS_VERIFY 0x08 +struct keyctl_pkey_query { + __u32 supported_ops; /* Which ops are supported */ + __u32 key_size; /* Size of the key in bits */ + __u16 max_data_size; /* Maximum size of raw data to sign in bytes */ + __u16 max_sig_size; /* Maximum size of signature in bytes */ + __u16 max_enc_size; /* Maximum size of encrypted blob in bytes */ + __u16 max_dec_size; /* Maximum size of decrypted blob in bytes */ + __u32 __spare[10]; +}; + +struct keyctl_pkey_params { + __s32 key_id; /* Serial no. of public key to use */ + __s32 password_id; /* Serial no. of password-containing key to use (or 0) */ + __u32 in_len; /* Input data size */ + union { + __u32 out_len; /* Output buffer size (encrypt/decrypt/sign) */ + __u32 in2_len; /* 2nd input data size (verify) */ + }; + __u32 __spare[4]; +}; + #endif /* _LINUX_KEYCTL_H */ 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 c8783b3b628c..6298b651e522 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -136,6 +136,21 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option, return keyctl_dh_compute(compat_ptr(arg2), compat_ptr(arg3), arg4); + case KEYCTL_PKEY_QUERY: + return keyctl_pkey_query(arg2, arg3, 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 8ec7a528365d..7da61fb8c6b4 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -269,6 +269,45 @@ 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, 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, key_serial_t password, + 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 3b135a0af344..4414c959fad3 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1691,6 +1691,29 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, (char __user *) arg3, (size_t) arg4); + case KEYCTL_PKEY_QUERY: + return keyctl_pkey_query((key_serial_t)arg2, + (key_serial_t)arg3, + (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..7f51db984aaa --- /dev/null +++ b/security/keys/keyctl_pkey.c @@ -0,0 +1,335 @@ +/* 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 +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static void keyctl_pkey_params_free(struct kernel_pkey_params *params) +{ + kfree(params->info); + key_put(params->key); + key_put(params->password); +} + +enum { + Opt_err = -1, + Opt_enc, /* "enc=" eg. "enc=oaep" */ + Opt_hash, /* "hash=" 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, + key_serial_t password_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; + + if (password_id) { + key_ref = lookup_user_key(password_id, 0, KEY_NEED_SEARCH); + if (IS_ERR(key_ref)) + return PTR_ERR(key_ref); + + params->password = key_ref_to_ptr(key_ref); + if (params->password->type != &key_type_logon) + return -EINVAL; + } + + 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, uparams.password_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, key_serial_t password_id, + const char __user *_info, + struct keyctl_pkey_query __user *_res) +{ + struct kernel_pkey_params params; + struct kernel_pkey_query res; + long ret; + + memset(¶ms, 0, sizeof(params)); + + ret = keyctl_pkey_params_get(id, password_id, _info, ¶ms); + if (ret < 0) + goto error; + + ret = params.key->type->asym_query(¶ms, &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(¶ms); + 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 needed, a password may be provided to unlock the private key in a logon + * key whose serial number is in _params->password_id. + * + * 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, ¶ms); + if (ret < 0) + 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 = kzalloc(params.out_len, GFP_KERNEL); + if (!out) + goto error_in; + + ret = params.key->type->asym_eds_op(¶ms, 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(¶ms); + 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, + ¶ms); + 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(¶ms, in, in2); + + kfree(in2); +error_in: + kfree(in); +error_params: + keyctl_pkey_params_free(¶ms); + return ret; +}