crypt_backend.h File Reference

Non-public crypto interface. More...

Macros
#define	AES_CRT128_BLOCK_SIZE   16
	AES block size in bytes. More...
#define	PKT_PEM   (0)
	Legacy PEM keys (openssh-7.7 and earlier, paraslash.0.6.2 and earlier) More...
#define	PKT_OPENSSH   (1)
	OPENSSH keys (since openssh-7.8, paraslash.0.6.3) More...

Functions
int	decode_public_key (const char *filename, unsigned char **blob, size_t *decoded_size)
	Perform sanity checks and base64-decode an ssh-rsa key. More...
int	decode_private_key (const char *key_file, unsigned char **result, size_t *blob_size)
	Decode an openssh-v1 (aka RFC4716) or PEM (aka ASN.1) private key. More...
int	check_private_key_file (const char *file)
	Check existence and permissions of a private key file. More...
int	find_openssh_bignum_offset (const unsigned char *data, int len)
	Check header of an openssh private key and compute bignum offset. More...

Detailed Description

Non-public crypto interface.

Macro Definition Documentation

AES_CRT128_BLOCK_SIZE

#define AES_CRT128_BLOCK_SIZE   16

AES block size in bytes.

PKT_PEM

#define PKT_PEM   (0)

Legacy PEM keys (openssh-7.7 and earlier, paraslash.0.6.2 and earlier)

PKT_OPENSSH

#define PKT_OPENSSH   (1)

OPENSSH keys (since openssh-7.8, paraslash.0.6.3)

Function Documentation

decode_public_key()

int decode_public_key	(	const char *	filename,
		unsigned char **	blob,
		size_t *	decoded_size
	)

Perform sanity checks and base64-decode an ssh-rsa key.

Parameters

filename	The public key file (usually id_rsa.pub).
blob	Pointer to base64-decoded blob is returned here.
decoded_size	The size of the decoded blob.

The memory pointed at by the returned blob pointer has to be freed by the caller.

Returns

On success, the offset in bytes of the start of the key values (modulus, exponent..). This is the number of bytes to skip from the blob until the start of the first encoded number. On failure, a negative error code is returned.

See also

uudecode().

References mmap_full_file().

Referenced by apc_get_pubkey().

decode_private_key()

int decode_private_key	(	const char *	key_file,
		unsigned char **	result,
		size_t *	blob_size
	)

Decode an openssh-v1 (aka RFC4716) or PEM (aka ASN.1) private key.

Parameters

key_file	The private key file (usually id_rsa).
result	Pointer to base64-decoded blob is returned here.
blob_size	The size of the decoded blob.

This only checks header and footer and base64-decodes the part in between. No attempt to read the decoded part is made.

Returns

Negative on errors, PKT_PEM or PKT_OPENSSH on success, indicating the type of key.

References alloc(), base64_decode(), mmap_full_file(), PARA_INFO_LOG, para_isspace, para_munmap(), PARA_WARNING_LOG, PKT_OPENSSH, PKT_PEM, PRIVATE_OPENSSH_KEY_FOOTER, PRIVATE_OPENSSH_KEY_HEADER, PRIVATE_PEM_KEY_FOOTER, and PRIVATE_PEM_KEY_HEADER.

check_private_key_file()

int check_private_key_file

(

const char *

file

)

Check existence and permissions of a private key file.

Parameters

file	The path of the key file.

This checks whether the file exists and its permissions are restrictive enough. It is considered an error if we own the file and it is readable for others.

Returns

Standard.

References ERRNO_TO_PARA_ERROR.

Referenced by apc_priv_decrypt().

find_openssh_bignum_offset()

int find_openssh_bignum_offset	(	const unsigned char *	data,
		int	len
	)

Check header of an openssh private key and compute bignum offset.

Parameters

data	The base64-decoded key.
len	The size of the decoded key.

Several assumptions are made about the key. Most notably, we only support single unencrypted keys without comments.

Returns

The offset at which the first bignum of the private key (the public exponent n) starts. Negative error code on failure.