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use std::marker::PhantomData;
use std::{mem, ptr};
use std::os::raw;
use std::os::raw::c_char;
use cose::SignatureAlgorithm;
type SECItemType = raw::c_uint; // TODO: actually an enum - is this the right size?
const SI_BUFFER: SECItemType = 0; // called siBuffer in NSS
#[repr(C)]
struct SECItem {
typ: SECItemType,
data: *const u8,
len: raw::c_uint,
}
impl SECItem {
fn maybe_new(data: &[u8]) -> Result<SECItem, NSSError> {
if data.len() > u32::max_value() as usize {
return Err(NSSError::InputTooLarge);
}
Ok(SECItem {
typ: SI_BUFFER,
data: data.as_ptr(),
len: data.len() as u32,
})
}
fn maybe_from_parts(data: *const u8, len: usize) -> Result<SECItem, NSSError> {
if len > u32::max_value() as usize {
return Err(NSSError::InputTooLarge);
}
Ok(SECItem {
typ: SI_BUFFER,
data: data,
len: len as u32,
})
}
}
/// Many NSS APIs take constant data input as SECItems. Some, however, output data as SECItems.
/// To represent this, we define another type of mutable SECItem.
#[repr(C)]
struct SECItemMut<'a> {
typ: SECItemType,
data: *mut u8,
len: raw::c_uint,
_marker: PhantomData<&'a mut Vec<u8>>,
}
impl<'a> SECItemMut<'a> {
/// Given a mutable reference to a Vec<u8> that has a particular allocated capacity, create a
/// SECItemMut that points to the vec and has the same capacity.
/// The input vec is not expected to have any actual contents, and in any case is cleared.
fn maybe_from_empty_preallocated_vec(vec: &'a mut Vec<u8>) -> Result<SECItemMut<'a>, NSSError> {
if vec.capacity() > u32::max_value() as usize {
return Err(NSSError::InputTooLarge);
}
vec.clear();
Ok(SECItemMut {
typ: SI_BUFFER,
data: vec.as_mut_ptr(),
len: vec.capacity() as u32,
_marker: PhantomData,
})
}
}
#[repr(C)]
struct CkRsaPkcsPssParams {
// Called CK_RSA_PKCS_PSS_PARAMS in NSS
hash_alg: CkMechanismType, // Called hashAlg in NSS
mgf: CkRsaPkcsMgfType,
s_len: raw::c_ulong, // Called sLen in NSS
}
impl CkRsaPkcsPssParams {
fn new() -> CkRsaPkcsPssParams {
CkRsaPkcsPssParams {
hash_alg: CKM_SHA256,
mgf: CKG_MGF1_SHA256,
s_len: 32,
}
}
fn get_params_item(&self) -> Result<SECItem, NSSError> {
// This isn't entirely NSS' fault, but it mostly is.
let params_ptr: *const CkRsaPkcsPssParams = self;
let params_ptr: *const u8 = params_ptr as *const u8;
let params_secitem =
SECItem::maybe_from_parts(params_ptr, mem::size_of::<CkRsaPkcsPssParams>())?;
Ok(params_secitem)
}
}
type CkMechanismType = raw::c_ulong; // called CK_MECHANISM_TYPE in NSS
const CKM_ECDSA: CkMechanismType = 0x0000_1041;
const CKM_RSA_PKCS_PSS: CkMechanismType = 0x0000_000D;
const CKM_SHA256: CkMechanismType = 0x0000_0250;
type CkRsaPkcsMgfType = raw::c_ulong; // called CK_RSA_PKCS_MGF_TYPE in NSS
const CKG_MGF1_SHA256: CkRsaPkcsMgfType = 0x0000_0002;
type SECStatus = raw::c_int; // TODO: enum - right size?
const SEC_SUCCESS: SECStatus = 0; // Called SECSuccess in NSS
const SEC_FAILURE: SECStatus = -1; // Called SECFailure in NSS
enum SECKEYPublicKey {}
enum SECKEYPrivateKey {}
enum PK11SlotInfo {}
enum CERTCertificate {}
enum CERTCertDBHandle {}
const SHA256_LENGTH: usize = 32;
const SHA384_LENGTH: usize = 48;
const SHA512_LENGTH: usize = 64;
// TODO: ugh this will probably have a platform-specific name...
#[link(name = "nss3")]
extern "C" {
fn PK11_HashBuf(
hashAlg: HashAlgorithm,
out: *mut u8,
data_in: *const u8, // called "in" in NSS
len: raw::c_int,
) -> SECStatus;
fn PK11_VerifyWithMechanism(
key: *const SECKEYPublicKey,
mechanism: CkMechanismType,
param: *const SECItem,
sig: *const SECItem,
hash: *const SECItem,
wincx: *const raw::c_void,
) -> SECStatus;
fn SECKEY_DestroyPublicKey(pubk: *const SECKEYPublicKey);
fn CERT_GetDefaultCertDB() -> *const CERTCertDBHandle;
fn CERT_DestroyCertificate(cert: *mut CERTCertificate);
fn CERT_NewTempCertificate(
handle: *const CERTCertDBHandle,
derCert: *const SECItem,
nickname: *const c_char,
isperm: bool,
copyDER: bool,
) -> *mut CERTCertificate;
fn CERT_ExtractPublicKey(cert: *const CERTCertificate) -> *const SECKEYPublicKey;
fn PK11_ImportDERPrivateKeyInfoAndReturnKey(
slot: *mut PK11SlotInfo,
derPKI: *const SECItem,
nickname: *const SECItem,
publicValue: *const SECItem,
isPerm: bool,
isPrivate: bool,
keyUsage: u32,
privk: *mut *mut SECKEYPrivateKey,
wincx: *const u8,
) -> SECStatus;
fn PK11_GetInternalSlot() -> *mut PK11SlotInfo;
fn PK11_FreeSlot(slot: *mut PK11SlotInfo);
fn PK11_SignatureLen(key: *const SECKEYPrivateKey) -> usize;
fn PK11_SignWithMechanism(
key: *const SECKEYPrivateKey,
mech: CkMechanismType,
param: *const SECItem,
sig: *mut SECItemMut,
hash: *const SECItem,
) -> SECStatus;
}
/// An error type describing errors that may be encountered during verification.
#[derive(Debug, PartialEq)]
pub enum NSSError {
ImportCertError,
DecodingPKCS8Failed,
InputTooLarge,
LibraryFailure,
SignatureVerificationFailed,
SigningFailed,
ExtractPublicKeyFailed,
}
#[derive(Debug, PartialEq, Clone)]
#[repr(C)]
enum HashAlgorithm {
SHA256 = 191,
SHA384 = 192,
SHA512 = 193,
}
fn hash(payload: &[u8], signature_algorithm: &SignatureAlgorithm) -> Result<Vec<u8>, NSSError> {
if payload.len() > raw::c_int::max_value() as usize {
return Err(NSSError::InputTooLarge);
}
let (hash_algorithm, digest_length) = match *signature_algorithm {
SignatureAlgorithm::ES256 => (HashAlgorithm::SHA256, SHA256_LENGTH),
SignatureAlgorithm::ES384 => (HashAlgorithm::SHA384, SHA384_LENGTH),
SignatureAlgorithm::ES512 => (HashAlgorithm::SHA512, SHA512_LENGTH),
SignatureAlgorithm::PS256 => (HashAlgorithm::SHA256, SHA256_LENGTH),
};
let mut hash_buf = vec![0; digest_length];
let len: raw::c_int = payload.len() as raw::c_int;
let hash_result =
unsafe { PK11_HashBuf(hash_algorithm, hash_buf.as_mut_ptr(), payload.as_ptr(), len) };
if hash_result != SEC_SUCCESS {
return Err(NSSError::LibraryFailure);
}
Ok(hash_buf)
}
/// Main entrypoint for verification. Given a signature algorithm, the bytes of a subject public key
/// info, a payload, and a signature over the payload, returns a result based on the outcome of
/// decoding the subject public key info and running the signature verification algorithm on the
/// signed data.
pub fn verify_signature(
signature_algorithm: &SignatureAlgorithm,
cert: &[u8],
payload: &[u8],
signature: &[u8],
) -> Result<(), NSSError> {
let slot = unsafe { PK11_GetInternalSlot() };
if slot.is_null() {
return Err(NSSError::LibraryFailure);
}
defer!(unsafe {
PK11_FreeSlot(slot);
});
let hash_buf = hash(payload, signature_algorithm).unwrap();
let hash_item = SECItem::maybe_new(hash_buf.as_slice())?;
// Import DER cert into NSS.
let der_cert = SECItem::maybe_new(cert)?;
let db_handle = unsafe { CERT_GetDefaultCertDB() };
if db_handle.is_null() {
// TODO #28
return Err(NSSError::LibraryFailure);
}
let nss_cert =
unsafe { CERT_NewTempCertificate(db_handle, &der_cert, ptr::null(), false, true) };
if nss_cert.is_null() {
return Err(NSSError::ImportCertError);
}
defer!(unsafe {
CERT_DestroyCertificate(nss_cert);
});
let key = unsafe { CERT_ExtractPublicKey(nss_cert) };
if key.is_null() {
return Err(NSSError::ExtractPublicKeyFailed);
}
defer!(unsafe {
SECKEY_DestroyPublicKey(key);
});
let signature_item = SECItem::maybe_new(signature)?;
let mechanism = match *signature_algorithm {
SignatureAlgorithm::ES256 => CKM_ECDSA,
SignatureAlgorithm::ES384 => CKM_ECDSA,
SignatureAlgorithm::ES512 => CKM_ECDSA,
SignatureAlgorithm::PS256 => CKM_RSA_PKCS_PSS,
};
let rsa_pss_params = CkRsaPkcsPssParams::new();
let rsa_pss_params_item = rsa_pss_params.get_params_item()?;
let params_item = match *signature_algorithm {
SignatureAlgorithm::ES256 => ptr::null(),
SignatureAlgorithm::ES384 => ptr::null(),
SignatureAlgorithm::ES512 => ptr::null(),
SignatureAlgorithm::PS256 => &rsa_pss_params_item,
};
let null_cx_ptr: *const raw::c_void = ptr::null();
let result = unsafe {
PK11_VerifyWithMechanism(
key,
mechanism,
params_item,
&signature_item,
&hash_item,
null_cx_ptr,
)
};
match result {
SEC_SUCCESS => Ok(()),
SEC_FAILURE => Err(NSSError::SignatureVerificationFailed),
_ => Err(NSSError::LibraryFailure),
}
}
pub fn sign(
signature_algorithm: &SignatureAlgorithm,
pk8: &[u8],
payload: &[u8],
) -> Result<Vec<u8>, NSSError> {
let slot = unsafe { PK11_GetInternalSlot() };
if slot.is_null() {
return Err(NSSError::LibraryFailure);
}
defer!(unsafe {
PK11_FreeSlot(slot);
});
let pkcs8item = SECItem::maybe_new(pk8)?;
let mut key: *mut SECKEYPrivateKey = ptr::null_mut();
let ku_all = 0xFF;
let rv = unsafe {
PK11_ImportDERPrivateKeyInfoAndReturnKey(
slot,
&pkcs8item,
ptr::null(),
ptr::null(),
false,
false,
ku_all,
&mut key,
ptr::null(),
)
};
if rv != SEC_SUCCESS || key.is_null() {
return Err(NSSError::DecodingPKCS8Failed);
}
let mechanism = match *signature_algorithm {
SignatureAlgorithm::ES256 => CKM_ECDSA,
SignatureAlgorithm::ES384 => CKM_ECDSA,
SignatureAlgorithm::ES512 => CKM_ECDSA,
SignatureAlgorithm::PS256 => CKM_RSA_PKCS_PSS,
};
let rsa_pss_params = CkRsaPkcsPssParams::new();
let rsa_pss_params_item = rsa_pss_params.get_params_item()?;
let params_item = match *signature_algorithm {
SignatureAlgorithm::ES256 => ptr::null(),
SignatureAlgorithm::ES384 => ptr::null(),
SignatureAlgorithm::ES512 => ptr::null(),
SignatureAlgorithm::PS256 => &rsa_pss_params_item,
};
let signature_len = unsafe { PK11_SignatureLen(key) };
// Allocate enough space for the signature.
let mut signature: Vec<u8> = Vec::with_capacity(signature_len);
let hash_buf = hash(payload, signature_algorithm).unwrap();
let hash_item = SECItem::maybe_new(hash_buf.as_slice())?;
{
// Get a mutable SECItem on the preallocated signature buffer. PK11_SignWithMechanism will
// fill the SECItem's buf with the bytes of the signature.
let mut signature_item = SECItemMut::maybe_from_empty_preallocated_vec(&mut signature)?;
let rv = unsafe {
PK11_SignWithMechanism(key, mechanism, params_item, &mut signature_item, &hash_item)
};
if rv != SEC_SUCCESS || signature_item.len as usize != signature_len {
return Err(NSSError::SigningFailed);
}
}
unsafe {
// Now that the bytes of the signature have been filled out, set its length.
signature.set_len(signature_len);
}
Ok(signature)
}