dmverity

Documentation

Index

• Constants
• func Format(dataDevice string, hashDevice string, opts *DmVerityParams) (rootHash string, err error)
• type DmVerityParams
• type VeritySuperblock
  • func ReadSuperblock(filename string) (*VeritySuperblock, error)
  • func (sb *VeritySuperblock) Size() int
  • func (sb *VeritySuperblock) Validate() error

Constants

const (
	// DefaultVerityFormat corresponds to veritysetup's default option for the --format argument which
	// currently is 1. This corresponds to the hash_type field of a dm-verity superblock.
	DefaultVerityFormat = 1
	// DefaultSuperblockVersion corresponds to the superblock version. Version 1 is the only one
	// currently supported by veritysetup. This corresponds to the version field of a dm-verity superblock.
	DefaultSuperblockVersion = 1
)

Functions

func Format

func Format(dataDevice string, hashDevice string, opts *DmVerityParams) (rootHash string, err error)

Format runs "veritysetup format" with the passed parameters and returns the dm-verity root hash.

"veritysetup format" calculates the hash verification data for dataDevice and stores them in hashDevice including the dm-verity superblock. The root hash is retrieved from the command's stdout.

Types

type DmVerityParams

type DmVerityParams struct {
	Format        uint8  `json:"format"`
	Hash          string `json:"hash"`
	DataBlocks    uint64 `json:"data-blocks"`
	DataBlockSize uint64 `json:"data-block-size"`
	HashBlockSize uint64 `json:"hash-block-size"`
	Salt          string `json:"salt"`
}

DmVerityParams contains the options to veritysetup format.

type VeritySuperblock

type VeritySuperblock struct {
	Signature     [8]uint8  /* "verity\0\0" */
	Version       uint32    /* superblock version */
	HashType      uint32    /* 0 - Chrome OS, 1 - normal */
	Uuid          [16]uint8 /* UUID of hash device */
	Algorithm     [32]uint8 /* hash algorithm name */
	DataBlockSize uint32    /* data block in bytes */
	HashBlockSize uint32    /* hash block in bytes */
	DataBlocks    uint64    /* number of data blocks */
	SaltSize      uint16    /* salt size */
	Pad1          [6]uint8
	Salt          [256]uint8 /* salt */
	Pad2          [168]uint8
}

VeritySuperblock represents the dm-verity superblock structure.

It mirrors cryptsetup's verity_sb structure from https://gitlab.com/cryptsetup/cryptsetup/-/blob/main/lib/verity/verity.c?ref_type=heads#L25

func ReadSuperblock

func ReadSuperblock(filename string) (*VeritySuperblock, error)

ReadSuperblock reads the dm-verity superblock from a dm-verity hash file.

func (*VeritySuperblock) Size

func (sb *VeritySuperblock) Size() int

func (*VeritySuperblock) Validate

func (sb *VeritySuperblock) Validate() error

Validate will perform consistency checks over an extracted superblock to determine whether it's a valid superblock or not.