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authorStephen Rothwell <sfr@canb.auug.org.au>2017-02-17 12:14:28 +1100
committerStephen Rothwell <sfr@canb.auug.org.au>2017-02-17 12:14:28 +1100
commita3613457d28b1bda7bdb188706f2d7fcae33875d (patch)
treecda24c8f0a59f32bc37cf21fcc9abf484c1baefd /Documentation
parentb7e522b5644499784cb03674ce4ea297b150c105 (diff)
parented51e44e914c634bfd8435037474ebb0b47db956 (diff)
Merge remote-tracking branch 'keys/keys-next'
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/crypto/asymmetric-keys.txt26
-rw-r--r--Documentation/security/keys.txt217
2 files changed, 238 insertions, 5 deletions
diff --git a/Documentation/crypto/asymmetric-keys.txt b/Documentation/crypto/asymmetric-keys.txt
index 2b7816dea370..b33a13ce8c37 100644
--- a/Documentation/crypto/asymmetric-keys.txt
+++ b/Documentation/crypto/asymmetric-keys.txt
@@ -182,6 +182,10 @@ and looks like the following:
void (*describe)(const struct key *key, struct seq_file *m);
void (*destroy)(void *payload);
+ int (*query)(const struct kernel_pkey_params *params,
+ struct kernel_pkey_query *info);
+ int (*eds_op)(struct kernel_pkey_params *params,
+ const void *in, void *out);
int (*verify_signature)(const struct key *key,
const struct public_key_signature *sig);
};
@@ -206,12 +210,22 @@ There are a number of operations defined by the subtype:
asymmetric key will look after freeing the fingerprint and releasing the
reference on the subtype module.
- (3) verify_signature().
+ (3) query().
- Optional. These are the entry points for the key usage operations.
- Currently there is only the one defined. If not set, the caller will be
- given -ENOTSUPP. The subtype may do anything it likes to implement an
- operation, including offloading to hardware.
+ Mandatory. This is a function for querying the capabilities of a key.
+
+ (4) eds_op().
+
+ Optional. This is the entry point for the encryption, decryption and
+ signature creation operations (which are distinguished by the operation ID
+ in the parameter struct). The subtype may do anything it likes to
+ implement an operation, including offloading to hardware.
+
+ (5) verify_signature().
+
+ Optional. This is the entry point for signature verification. The
+ subtype may do anything it likes to implement an operation, including
+ offloading to hardware.
==========================
@@ -233,6 +247,8 @@ Examples of blob formats for which parsers could be implemented include:
- X.509 ASN.1 stream.
- Pointer to TPM key.
- Pointer to UEFI key.
+ - PKCS#8 private key [RFC 5208].
+ - PKCS#5 encrypted private key [RFC 2898].
During key instantiation each parser in the list is tried until one doesn't
return -EBADMSG.
diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index 3849814bfe6d..6844dcbba1ba 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt
@@ -857,6 +857,117 @@ 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_id, 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. 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;
+ __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
+
+ info is a string of key=value pairs that supply supplementary information.
+ These include:
+
+ enc=<encoding> 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=<algo> 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".
+
+ 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.
+
+
===============
KERNEL SERVICES
===============
@@ -1432,6 +1543,112 @@ The structure has a number of fields, some of which are mandatory:
The authorisation key.
+ (*) int (*asym_eds_op)(struct kernel_pkey_params *params,
+ const void *in, void *out);
+ int (*asym_verify_signature)(struct kernel_pkey_params *params,
+ const void *in, const void *in2);
+
+ These methods are optional. If provided the first allows a key to be
+ used to encrypt, decrypt or sign a blob of data, and the second allows a
+ key to verify a signature.
+
+ In all cases, the following information is provided in the params block:
+
+ struct kernel_pkey_params {
+ struct key *key;
+ const char *encoding;
+ const char *hash_algo;
+ char *info;
+ __u32 in_len;
+ union {
+ __u32 out_len;
+ __u32 in2_len;
+ };
+ enum kernel_pkey_operation op : 8;
+ };
+
+ This includes the key to be used; an optional string indicating the
+ encoding to use (for instance, "pkcs1" may be used with an RSA key to
+ indicate RSASSA-PKCS1-v1.5 or RSAES-PKCS1-v1.5 encoding); the name of the
+ hash algorithm used to generate the data for a signature (if appropriate);
+ the sizes of the input and output (or second input) buffers; and the ID of
+ the operation to be performed.
+
+ For a given operation ID, the input and output buffers are used as
+ follows:
+
+ Operation ID in,in_len out,out_len in2,in2_len
+ ======================= =============== =============== ===============
+ kernel_pkey_encrypt Raw data Encrypted data -
+ kernel_pkey_decrypt Encrypted data Raw data -
+ kernel_pkey_sign Raw data Signature -
+ kernel_pkey_verify Raw data - Signature
+
+ asym_eds_op() deals with encryption, decryption and signature creation as
+ specified by params->op. Note that params->op is also set for
+ asym_verify_signature().
+
+ Encrypting and signature creation both take raw data in the input buffer
+ and return the encrypted result in the output buffer. Padding may have
+ been added if an encoding was set. In the case of signature creation,
+ depending on the encoding, the padding created may need to indicate the
+ digest algorithm - the name of which should be supplied in hash_algo.
+
+ Decryption takes encrypted data in the input buffer and returns the raw
+ data in the output buffer. Padding will get checked and stripped off if
+ an encoding was set.
+
+ Verification takes raw data in the input buffer and the signature in the
+ second input buffer and checks that the one matches the other. Padding
+ will be validated. Depending on the encoding, the digest algorithm used
+ to generate the raw data may need to be indicated in hash_algo.
+
+ If successful, asym_eds_op() should return the number of bytes written
+ into the output buffer. asym_verify_signature() should return 0.
+
+ A variety of errors may be returned, including EOPNOTSUPP if the operation
+ is not supported; EKEYREJECTED if verification fails; ENOPKG if the
+ required crypto isn't available.
+
+
+ (*) int (*asym_query)(const struct kernel_pkey_params *params,
+ struct kernel_pkey_query *info);
+
+ This method is optional. If provided it allows information about the
+ public or asymmetric key held in the key to be determined.
+
+ The parameter block is as for asym_eds_op() and co. but in_len and out_len
+ are unused. The encoding and hash_algo fields should be used to reduce
+ the returned buffer/data sizes as appropriate.
+
+ If successful, the following information is filled in:
+
+ struct kernel_pkey_query {
+ __u32 supported_ops;
+ __u32 key_size;
+ __u16 max_data_size;
+ __u16 max_sig_size;
+ __u16 max_enc_size;
+ __u16 max_dec_size;
+ };
+
+ The supported_ops field will contain a bitmask indicating what operations
+ are supported by the key, including encryption of a blob, decryption of a
+ blob, signing a blob and verifying the signature on a blob. The following
+ constants are defined for this:
+
+ KEYCTL_SUPPORTS_{ENCRYPT,DECRYPT,SIGN,VERIFY}
+
+ The key_size field is the size of the key in bits. max_data_size and
+ max_sig_size are the maximum raw data and signature sizes for creation and
+ verification of a signature; max_enc_size and max_dec_size are the maximum
+ raw data and signature sizes for encryption and decryption. The
+ max_*_size fields are measured in bytes.
+
+ If successful, 0 will be returned. If the key doesn't support this,
+ EOPNOTSUPP will be returned.
+
+
============================
REQUEST-KEY CALLBACK SERVICE
============================