diff options
Diffstat (limited to 'security/manager/ssl/osclientcerts/src/backend_windows.rs')
| -rw-r--r-- | security/manager/ssl/osclientcerts/src/backend_windows.rs | 914 |
1 files changed, 914 insertions, 0 deletions
diff --git a/security/manager/ssl/osclientcerts/src/backend_windows.rs b/security/manager/ssl/osclientcerts/src/backend_windows.rs new file mode 100644 index 0000000000..2a80ff8354 --- /dev/null +++ b/security/manager/ssl/osclientcerts/src/backend_windows.rs @@ -0,0 +1,914 @@ +/* -*- Mode: rust; rust-indent-offset: 4 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#![allow(non_camel_case_types)] + +use pkcs11_bindings::*; +use rsclientcerts::error::{Error, ErrorType}; +use rsclientcerts::manager::{ClientCertsBackend, CryptokiObject, Sign, SlotType}; +use rsclientcerts::util::*; +use sha2::{Digest, Sha256}; +use std::convert::TryInto; +use std::ffi::{c_void, CStr, CString}; +use std::ops::Deref; +use std::slice; +use winapi::shared::bcrypt::*; +use winapi::shared::minwindef::{DWORD, PBYTE}; +use winapi::um::errhandlingapi::GetLastError; +use winapi::um::ncrypt::*; +use winapi::um::wincrypt::{HCRYPTHASH, HCRYPTPROV, *}; + +// winapi has some support for ncrypt.h, but not for this function. +extern "system" { + fn NCryptSignHash( + hKey: NCRYPT_KEY_HANDLE, + pPaddingInfo: *mut c_void, + pbHashValue: PBYTE, + cbHashValue: DWORD, + pbSignature: PBYTE, + cbSignature: DWORD, + pcbResult: *mut DWORD, + dwFlags: DWORD, + ) -> SECURITY_STATUS; +} + +/// Given a `CERT_INFO`, tries to return the bytes of the subject distinguished name as formatted by +/// `CertNameToStrA` using the flag `CERT_SIMPLE_NAME_STR`. This is used as the label for the +/// certificate. +fn get_cert_subject_dn(cert_info: &CERT_INFO) -> Result<Vec<u8>, Error> { + let mut cert_info_subject = cert_info.Subject; + let subject_dn_len = unsafe { + CertNameToStrA( + X509_ASN_ENCODING, + &mut cert_info_subject, + CERT_SIMPLE_NAME_STR, + std::ptr::null_mut(), + 0, + ) + }; + // subject_dn_len includes the terminating null byte. + let mut subject_dn_string_bytes: Vec<u8> = vec![0; subject_dn_len as usize]; + let subject_dn_len = unsafe { + CertNameToStrA( + X509_ASN_ENCODING, + &mut cert_info_subject, + CERT_SIMPLE_NAME_STR, + subject_dn_string_bytes.as_mut_ptr() as *mut i8, + subject_dn_string_bytes + .len() + .try_into() + .map_err(|_| error_here!(ErrorType::ValueTooLarge))?, + ) + }; + if subject_dn_len as usize != subject_dn_string_bytes.len() { + return Err(error_here!(ErrorType::ExternalError)); + } + Ok(subject_dn_string_bytes) +} + +/// Represents a certificate for which there exists a corresponding private key. +pub struct Cert { + /// PKCS #11 object class. Will be `CKO_CERTIFICATE`. + class: Vec<u8>, + /// Whether or not this is on a token. Will be `CK_TRUE`. + token: Vec<u8>, + /// An identifier unique to this certificate. Must be the same as the ID for the private key. + id: Vec<u8>, + /// The bytes of a human-readable label for this certificate. Will be the subject DN. + label: Vec<u8>, + /// The DER bytes of the certificate. + value: Vec<u8>, + /// The DER bytes of the issuer distinguished name of the certificate. + issuer: Vec<u8>, + /// The DER bytes of the serial number of the certificate. + serial_number: Vec<u8>, + /// The DER bytes of the subject distinguished name of the certificate. + subject: Vec<u8>, + /// Which slot this certificate should be exposed on. + slot_type: SlotType, +} + +impl Cert { + fn new(cert_context: PCCERT_CONTEXT) -> Result<Cert, Error> { + let cert = unsafe { &*cert_context }; + let cert_info = unsafe { &*cert.pCertInfo }; + let value = + unsafe { slice::from_raw_parts(cert.pbCertEncoded, cert.cbCertEncoded as usize) }; + let value = value.to_vec(); + let id = Sha256::digest(&value).to_vec(); + let label = get_cert_subject_dn(cert_info)?; + let (serial_number, issuer, subject) = read_encoded_certificate_identifiers(&value)?; + Ok(Cert { + class: serialize_uint(CKO_CERTIFICATE)?, + token: serialize_uint(CK_TRUE)?, + id, + label, + value, + issuer, + serial_number, + subject, + slot_type: SlotType::Modern, + }) + } + + fn class(&self) -> &[u8] { + &self.class + } + + fn token(&self) -> &[u8] { + &self.token + } + + fn id(&self) -> &[u8] { + &self.id + } + + fn label(&self) -> &[u8] { + &self.label + } + + fn value(&self) -> &[u8] { + &self.value + } + + fn issuer(&self) -> &[u8] { + &self.issuer + } + + fn serial_number(&self) -> &[u8] { + &self.serial_number + } + + fn subject(&self) -> &[u8] { + &self.subject + } +} + +impl CryptokiObject for Cert { + fn matches(&self, slot_type: SlotType, attrs: &[(CK_ATTRIBUTE_TYPE, Vec<u8>)]) -> bool { + if slot_type != self.slot_type { + return false; + } + for (attr_type, attr_value) in attrs { + let comparison = match *attr_type { + CKA_CLASS => self.class(), + CKA_TOKEN => self.token(), + CKA_LABEL => self.label(), + CKA_ID => self.id(), + CKA_VALUE => self.value(), + CKA_ISSUER => self.issuer(), + CKA_SERIAL_NUMBER => self.serial_number(), + CKA_SUBJECT => self.subject(), + _ => return false, + }; + if attr_value.as_slice() != comparison { + return false; + } + } + true + } + + fn get_attribute(&self, attribute: CK_ATTRIBUTE_TYPE) -> Option<&[u8]> { + let result = match attribute { + CKA_CLASS => self.class(), + CKA_TOKEN => self.token(), + CKA_LABEL => self.label(), + CKA_ID => self.id(), + CKA_VALUE => self.value(), + CKA_ISSUER => self.issuer(), + CKA_SERIAL_NUMBER => self.serial_number(), + CKA_SUBJECT => self.subject(), + _ => return None, + }; + Some(result) + } +} + +struct CertContext(PCCERT_CONTEXT); + +impl CertContext { + fn new(cert: PCCERT_CONTEXT) -> CertContext { + CertContext(unsafe { CertDuplicateCertificateContext(cert) }) + } +} + +impl Drop for CertContext { + fn drop(&mut self) { + unsafe { + CertFreeCertificateContext(self.0); + } + } +} + +impl Deref for CertContext { + type Target = PCCERT_CONTEXT; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} + +enum KeyHandle { + NCrypt(NCRYPT_KEY_HANDLE), + CryptoAPI(HCRYPTPROV, DWORD), +} + +impl KeyHandle { + fn from_cert(cert: &CertContext) -> Result<KeyHandle, Error> { + let mut key_handle = 0; + let mut key_spec = 0; + let mut must_free = 0; + unsafe { + if CryptAcquireCertificatePrivateKey( + **cert, + CRYPT_ACQUIRE_PREFER_NCRYPT_KEY_FLAG, + std::ptr::null_mut(), + &mut key_handle, + &mut key_spec, + &mut must_free, + ) != 1 + { + return Err(error_here!( + ErrorType::ExternalError, + GetLastError().to_string() + )); + } + } + if must_free == 0 { + return Err(error_here!(ErrorType::ExternalError)); + } + if key_spec == CERT_NCRYPT_KEY_SPEC { + Ok(KeyHandle::NCrypt(key_handle as NCRYPT_KEY_HANDLE)) + } else { + Ok(KeyHandle::CryptoAPI(key_handle as HCRYPTPROV, key_spec)) + } + } + + fn sign( + &self, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + do_signature: bool, + key_type: KeyType, + ) -> Result<Vec<u8>, Error> { + match &self { + KeyHandle::NCrypt(ncrypt_handle) => { + sign_ncrypt(ncrypt_handle, data, params, do_signature, key_type) + } + KeyHandle::CryptoAPI(hcryptprov, key_spec) => { + sign_cryptoapi(hcryptprov, key_spec, data, params, do_signature) + } + } + } +} + +impl Drop for KeyHandle { + fn drop(&mut self) { + match self { + KeyHandle::NCrypt(ncrypt_handle) => unsafe { + let _ = NCryptFreeObject(*ncrypt_handle); + }, + KeyHandle::CryptoAPI(hcryptprov, _) => unsafe { + let _ = CryptReleaseContext(*hcryptprov, 0); + }, + } + } +} + +fn sign_ncrypt( + ncrypt_handle: &NCRYPT_KEY_HANDLE, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + do_signature: bool, + key_type: KeyType, +) -> Result<Vec<u8>, Error> { + let mut sign_params = SignParams::new(key_type, params)?; + let params_ptr = sign_params.params_ptr(); + let flags = sign_params.flags(); + let mut data = data.to_vec(); + let mut signature_len = 0; + // We call NCryptSignHash twice: the first time to get the size of the buffer we need to + // allocate and then again to actually sign the data, if `do_signature` is `true`. + let status = unsafe { + NCryptSignHash( + *ncrypt_handle, + params_ptr, + data.as_mut_ptr(), + data.len() + .try_into() + .map_err(|_| error_here!(ErrorType::ValueTooLarge))?, + std::ptr::null_mut(), + 0, + &mut signature_len, + flags, + ) + }; + // 0 is "ERROR_SUCCESS" (but "ERROR_SUCCESS" is unsigned, whereas SECURITY_STATUS is signed) + if status != 0 { + return Err(error_here!(ErrorType::ExternalError, status.to_string())); + } + let mut signature = vec![0; signature_len as usize]; + if !do_signature { + return Ok(signature); + } + let mut final_signature_len = signature_len; + let status = unsafe { + NCryptSignHash( + *ncrypt_handle, + params_ptr, + data.as_mut_ptr(), + data.len() + .try_into() + .map_err(|_| error_here!(ErrorType::ValueTooLarge))?, + signature.as_mut_ptr(), + signature_len, + &mut final_signature_len, + flags, + ) + }; + if status != 0 { + return Err(error_here!(ErrorType::ExternalError, status.to_string())); + } + if final_signature_len != signature_len { + return Err(error_here!(ErrorType::ExternalError)); + } + Ok(signature) +} + +fn sign_cryptoapi( + hcryptprov: &HCRYPTPROV, + key_spec: &DWORD, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + do_signature: bool, +) -> Result<Vec<u8>, Error> { + if params.is_some() { + return Err(error_here!(ErrorType::LibraryFailure)); + } + // data will be an encoded DigestInfo, which specifies the hash algorithm and bytes of the hash + // to sign. However, CryptoAPI requires directly specifying the bytes of the hash, so it must + // be extracted first. + let (_, hash_bytes) = read_digest_info(data)?; + let hash = HCryptHash::new(hcryptprov, hash_bytes)?; + let mut signature_len = 0; + if unsafe { + CryptSignHashW( + *hash, + *key_spec, + std::ptr::null_mut(), + 0, + std::ptr::null_mut(), + &mut signature_len, + ) + } != 1 + { + return Err(error_here!( + ErrorType::ExternalError, + unsafe { GetLastError() }.to_string() + )); + } + let mut signature = vec![0; signature_len as usize]; + if !do_signature { + return Ok(signature); + } + let mut final_signature_len = signature_len; + if unsafe { + CryptSignHashW( + *hash, + *key_spec, + std::ptr::null_mut(), + 0, + signature.as_mut_ptr(), + &mut final_signature_len, + ) + } != 1 + { + return Err(error_here!( + ErrorType::ExternalError, + unsafe { GetLastError() }.to_string() + )); + } + if final_signature_len != signature_len { + return Err(error_here!(ErrorType::ExternalError)); + } + // CryptoAPI returns the signature with the most significant byte last (little-endian), + // whereas PKCS#11 expects the most significant byte first (big-endian). + signature.reverse(); + Ok(signature) +} + +struct HCryptHash(HCRYPTHASH); + +impl HCryptHash { + fn new(hcryptprov: &HCRYPTPROV, hash_bytes: &[u8]) -> Result<HCryptHash, Error> { + let alg = match hash_bytes.len() { + 20 => CALG_SHA1, + 32 => CALG_SHA_256, + 48 => CALG_SHA_384, + 64 => CALG_SHA_512, + _ => { + return Err(error_here!(ErrorType::UnsupportedInput)); + } + }; + let mut hash: HCRYPTHASH = 0; + if unsafe { CryptCreateHash(*hcryptprov, alg, 0, 0, &mut hash) } != 1 { + return Err(error_here!( + ErrorType::ExternalError, + unsafe { GetLastError() }.to_string() + )); + } + if unsafe { CryptSetHashParam(hash, HP_HASHVAL, hash_bytes.as_ptr(), 0) } != 1 { + return Err(error_here!( + ErrorType::ExternalError, + unsafe { GetLastError() }.to_string() + )); + } + Ok(HCryptHash(hash)) + } +} + +impl Drop for HCryptHash { + fn drop(&mut self) { + unsafe { + CryptDestroyHash(self.0); + } + } +} + +impl Deref for HCryptHash { + type Target = HCRYPTHASH; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} + +// In some cases, the ncrypt API takes a pointer to a null-terminated wide-character string as a way +// of specifying an algorithm. The "right" way to do this would be to take the corresponding +// &'static str constant provided by the winapi crate, create an OsString from it, encode it as wide +// characters, and collect it into a Vec<u16>. However, since the implementation that provides this +// functionality isn't constant, we would have to manage the memory this creates and uses. Since +// rust structures generally can't be self-referrential, this memory would have to live elsewhere, +// and the nice abstractions we've created for this implementation start to break down. It's much +// simpler to hard-code the identifiers we support, since there are only four of them. +// The following arrays represent the identifiers "SHA1", "SHA256", "SHA384", and "SHA512", +// respectively. +const SHA1_ALGORITHM_STRING: &[u16] = &[83, 72, 65, 49, 0]; +const SHA256_ALGORITHM_STRING: &[u16] = &[83, 72, 65, 50, 53, 54, 0]; +const SHA384_ALGORITHM_STRING: &[u16] = &[83, 72, 65, 51, 56, 52, 0]; +const SHA512_ALGORITHM_STRING: &[u16] = &[83, 72, 65, 53, 49, 50, 0]; + +enum SignParams { + EC, + RSA_PKCS1(BCRYPT_PKCS1_PADDING_INFO), + RSA_PSS(BCRYPT_PSS_PADDING_INFO), +} + +impl SignParams { + fn new( + key_type: KeyType, + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + ) -> Result<SignParams, Error> { + // EC is easy, so handle that first. + match key_type { + KeyType::EC => return Ok(SignParams::EC), + KeyType::RSA => {} + } + // If `params` is `Some`, we're doing RSA-PSS. If it is `None`, we're doing RSA-PKCS1. + let pss_params = match params { + Some(pss_params) => pss_params, + None => { + // The hash algorithm should be encoded in the data to be signed, so we don't have to + // (and don't want to) specify a particular algorithm here. + return Ok(SignParams::RSA_PKCS1(BCRYPT_PKCS1_PADDING_INFO { + pszAlgId: std::ptr::null(), + })); + } + }; + let algorithm_string = match pss_params.hashAlg { + CKM_SHA_1 => SHA1_ALGORITHM_STRING, + CKM_SHA256 => SHA256_ALGORITHM_STRING, + CKM_SHA384 => SHA384_ALGORITHM_STRING, + CKM_SHA512 => SHA512_ALGORITHM_STRING, + _ => { + return Err(error_here!(ErrorType::UnsupportedInput)); + } + }; + Ok(SignParams::RSA_PSS(BCRYPT_PSS_PADDING_INFO { + pszAlgId: algorithm_string.as_ptr(), + cbSalt: pss_params.sLen, + })) + } + + fn params_ptr(&mut self) -> *mut std::ffi::c_void { + match self { + SignParams::EC => std::ptr::null_mut(), + SignParams::RSA_PKCS1(params) => { + params as *mut BCRYPT_PKCS1_PADDING_INFO as *mut std::ffi::c_void + } + SignParams::RSA_PSS(params) => { + params as *mut BCRYPT_PSS_PADDING_INFO as *mut std::ffi::c_void + } + } + } + + fn flags(&self) -> u32 { + match *self { + SignParams::EC => 0, + SignParams::RSA_PKCS1(_) => NCRYPT_PAD_PKCS1_FLAG, + SignParams::RSA_PSS(_) => NCRYPT_PAD_PSS_FLAG, + } + } +} + +/// A helper enum to identify a private key's type. We support EC and RSA. +#[allow(clippy::upper_case_acronyms)] +#[derive(Clone, Copy, Debug)] +pub enum KeyType { + EC, + RSA, +} + +/// Represents a private key for which there exists a corresponding certificate. +pub struct Key { + /// A handle on the OS mechanism that represents the certificate for this key. + cert: CertContext, + /// PKCS #11 object class. Will be `CKO_PRIVATE_KEY`. + class: Vec<u8>, + /// Whether or not this is on a token. Will be `CK_TRUE`. + token: Vec<u8>, + /// An identifier unique to this key. Must be the same as the ID for the certificate. + id: Vec<u8>, + /// Whether or not this key is "private" (can it be exported?). Will be CK_TRUE (it can't be + /// exported). + private: Vec<u8>, + /// PKCS #11 key type. Will be `CKK_EC` for EC, and `CKK_RSA` for RSA. + key_type: Vec<u8>, + /// If this is an RSA key, this is the value of the modulus as an unsigned integer. + modulus: Option<Vec<u8>>, + /// If this is an EC key, this is the DER bytes of the OID identifying the curve the key is on. + ec_params: Option<Vec<u8>>, + /// An enum identifying this key's type. + key_type_enum: KeyType, + /// Which slot this key should be exposed on. + slot_type: SlotType, + /// A handle on the OS mechanism that represents this key. + key_handle: Option<KeyHandle>, +} + +impl Key { + fn new(cert_context: PCCERT_CONTEXT) -> Result<Key, Error> { + let cert = unsafe { *cert_context }; + let cert_der = + unsafe { slice::from_raw_parts(cert.pbCertEncoded, cert.cbCertEncoded as usize) }; + let id = Sha256::digest(cert_der).to_vec(); + let id = id.to_vec(); + let cert_info = unsafe { &*cert.pCertInfo }; + let mut modulus = None; + let mut ec_params = None; + let spki = &cert_info.SubjectPublicKeyInfo; + let algorithm_oid = unsafe { CStr::from_ptr(spki.Algorithm.pszObjId) } + .to_str() + .map_err(|_| error_here!(ErrorType::ExternalError))?; + let (key_type_enum, key_type_attribute) = if algorithm_oid == szOID_RSA_RSA { + if spki.PublicKey.cUnusedBits != 0 { + return Err(error_here!(ErrorType::ExternalError)); + } + let public_key_bytes = unsafe { + std::slice::from_raw_parts(spki.PublicKey.pbData, spki.PublicKey.cbData as usize) + }; + let modulus_value = read_rsa_modulus(public_key_bytes)?; + modulus = Some(modulus_value); + (KeyType::RSA, CKK_RSA) + } else if algorithm_oid == szOID_ECC_PUBLIC_KEY { + let params = &spki.Algorithm.Parameters; + ec_params = Some( + unsafe { std::slice::from_raw_parts(params.pbData, params.cbData as usize) } + .to_vec(), + ); + (KeyType::EC, CKK_EC) + } else { + return Err(error_here!(ErrorType::LibraryFailure)); + }; + let cert = CertContext::new(cert_context); + Ok(Key { + cert, + class: serialize_uint(CKO_PRIVATE_KEY)?, + token: serialize_uint(CK_TRUE)?, + id, + private: serialize_uint(CK_TRUE)?, + key_type: serialize_uint(key_type_attribute)?, + modulus, + ec_params, + key_type_enum, + slot_type: SlotType::Modern, + key_handle: None, + }) + } + + fn class(&self) -> &[u8] { + &self.class + } + + fn token(&self) -> &[u8] { + &self.token + } + + fn id(&self) -> &[u8] { + &self.id + } + + fn private(&self) -> &[u8] { + &self.private + } + + fn key_type(&self) -> &[u8] { + &self.key_type + } + + fn modulus(&self) -> Option<&[u8]> { + match &self.modulus { + Some(modulus) => Some(modulus.as_slice()), + None => None, + } + } + + fn ec_params(&self) -> Option<&[u8]> { + match &self.ec_params { + Some(ec_params) => Some(ec_params.as_slice()), + None => None, + } + } + + fn sign_with_retry( + &mut self, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + do_signature: bool, + ) -> Result<Vec<u8>, Error> { + let result = self.sign_internal(data, params, do_signature); + if result.is_ok() { + return result; + } + // Some devices appear to not work well when the key handle is held for too long or if a + // card is inserted/removed while Firefox is running. Try refreshing the key handle. + debug!("sign failed: refreshing key handle"); + let _ = self.key_handle.take(); + self.sign_internal(data, params, do_signature) + } + + /// data: the data to sign + /// do_signature: if true, actually perform the signature. Otherwise, return a `Vec<u8>` of the + /// length the signature would be, if performed. + fn sign_internal( + &mut self, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + do_signature: bool, + ) -> Result<Vec<u8>, Error> { + // If this key hasn't been used for signing yet, there won't be a cached key handle. Obtain + // and cache it if this is the case. Doing so can cause the underlying implementation to + // show an authentication or pin prompt to the user. Caching the handle can avoid causing + // multiple prompts to be displayed in some cases. + if self.key_handle.is_none() { + let _ = self.key_handle.replace(KeyHandle::from_cert(&self.cert)?); + } + let key = match &self.key_handle { + Some(key) => key, + None => return Err(error_here!(ErrorType::LibraryFailure)), + }; + key.sign(data, params, do_signature, self.key_type_enum) + } +} + +impl CryptokiObject for Key { + fn matches(&self, slot_type: SlotType, attrs: &[(CK_ATTRIBUTE_TYPE, Vec<u8>)]) -> bool { + if slot_type != self.slot_type { + return false; + } + for (attr_type, attr_value) in attrs { + let comparison = match *attr_type { + CKA_CLASS => self.class(), + CKA_TOKEN => self.token(), + CKA_ID => self.id(), + CKA_PRIVATE => self.private(), + CKA_KEY_TYPE => self.key_type(), + CKA_MODULUS => { + if let Some(modulus) = self.modulus() { + modulus + } else { + return false; + } + } + CKA_EC_PARAMS => { + if let Some(ec_params) = self.ec_params() { + ec_params + } else { + return false; + } + } + _ => return false, + }; + if attr_value.as_slice() != comparison { + return false; + } + } + true + } + + fn get_attribute(&self, attribute: CK_ATTRIBUTE_TYPE) -> Option<&[u8]> { + match attribute { + CKA_CLASS => Some(self.class()), + CKA_TOKEN => Some(self.token()), + CKA_ID => Some(self.id()), + CKA_PRIVATE => Some(self.private()), + CKA_KEY_TYPE => Some(self.key_type()), + CKA_MODULUS => self.modulus(), + CKA_EC_PARAMS => self.ec_params(), + _ => None, + } + } +} + +impl Sign for Key { + fn get_signature_length( + &mut self, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + ) -> Result<usize, Error> { + match self.sign_with_retry(data, params, false) { + Ok(dummy_signature_bytes) => Ok(dummy_signature_bytes.len()), + Err(e) => Err(e), + } + } + + fn sign( + &mut self, + data: &[u8], + params: &Option<CK_RSA_PKCS_PSS_PARAMS>, + ) -> Result<Vec<u8>, Error> { + self.sign_with_retry(data, params, true) + } +} + +struct CertStore { + handle: HCERTSTORE, +} + +impl Drop for CertStore { + fn drop(&mut self) { + if !self.handle.is_null() { + unsafe { + CertCloseStore(self.handle, 0); + } + } + } +} + +impl Deref for CertStore { + type Target = HCERTSTORE; + + fn deref(&self) -> &Self::Target { + &self.handle + } +} + +impl CertStore { + fn new(handle: HCERTSTORE) -> CertStore { + CertStore { handle } + } +} + +// Given a pointer to a CERT_CHAIN_CONTEXT, enumerates each chain in the context and each element +// in each chain to gather every CERT_CONTEXT pointed to by the CERT_CHAIN_CONTEXT. +// https://docs.microsoft.com/en-us/windows/win32/api/wincrypt/ns-wincrypt-cert_chain_context says +// that the 0th element of the 0th chain will be the end-entity certificate. This certificate (if +// present), will be the 0th element of the returned Vec. +fn gather_cert_contexts(cert_chain_context: *const CERT_CHAIN_CONTEXT) -> Vec<*const CERT_CONTEXT> { + let mut cert_contexts = Vec::new(); + if cert_chain_context.is_null() { + return cert_contexts; + } + let cert_chain_context = unsafe { &*cert_chain_context }; + let cert_chains = unsafe { + std::slice::from_raw_parts( + cert_chain_context.rgpChain, + cert_chain_context.cChain as usize, + ) + }; + for cert_chain in cert_chains { + // First dereference the borrow. + let cert_chain = *cert_chain; + if cert_chain.is_null() { + continue; + } + // Then dereference the pointer. + let cert_chain = unsafe { &*cert_chain }; + let chain_elements = unsafe { + std::slice::from_raw_parts(cert_chain.rgpElement, cert_chain.cElement as usize) + }; + for chain_element in chain_elements { + let chain_element = *chain_element; // dereference borrow + if chain_element.is_null() { + continue; + } + let chain_element = unsafe { &*chain_element }; // dereference pointer + cert_contexts.push(chain_element.pCertContext); + } + } + cert_contexts +} + +pub struct Backend {} + +impl ClientCertsBackend for Backend { + type Cert = Cert; + type Key = Key; + + /// Attempts to enumerate certificates with private keys exposed by the OS. Currently only looks in + /// the "My" cert store of the current user. In the future this may look in more locations. + fn find_objects(&self) -> Result<(Vec<Cert>, Vec<Key>), Error> { + let mut certs = Vec::new(); + let mut keys = Vec::new(); + let location_flags = CERT_SYSTEM_STORE_CURRENT_USER + | CERT_STORE_OPEN_EXISTING_FLAG + | CERT_STORE_READONLY_FLAG; + let store_name = match CString::new("My") { + Ok(store_name) => store_name, + Err(_) => return Err(error_here!(ErrorType::LibraryFailure)), + }; + let store = CertStore::new(unsafe { + CertOpenStore( + CERT_STORE_PROV_SYSTEM_REGISTRY_A, + 0, + 0, + location_flags, + store_name.as_ptr() as *const winapi::ctypes::c_void, + ) + }); + if store.is_null() { + return Err(error_here!(ErrorType::ExternalError)); + } + let find_params = CERT_CHAIN_FIND_ISSUER_PARA { + cbSize: std::mem::size_of::<CERT_CHAIN_FIND_ISSUER_PARA>() as u32, + pszUsageIdentifier: std::ptr::null(), + dwKeySpec: 0, + dwAcquirePrivateKeyFlags: 0, + cIssuer: 0, + rgIssuer: std::ptr::null_mut(), + pfnFindCallback: None, + pvFindArg: std::ptr::null_mut(), + pdwIssuerChainIndex: std::ptr::null_mut(), + pdwIssuerElementIndex: std::ptr::null_mut(), + }; + let mut cert_chain_context: PCCERT_CHAIN_CONTEXT = std::ptr::null_mut(); + loop { + // CertFindChainInStore finds all certificates with private keys in the store. It also + // attempts to build a verified certificate chain to a trust anchor for each certificate. + // We gather and hold onto these extra certificates so that gecko can use them when + // filtering potential client certificates according to the acceptable CAs list sent by + // servers when they request client certificates. + cert_chain_context = unsafe { + CertFindChainInStore( + *store, + X509_ASN_ENCODING, + CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_FLAG + | CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_URL_FLAG, + CERT_CHAIN_FIND_BY_ISSUER, + &find_params as *const CERT_CHAIN_FIND_ISSUER_PARA + as *const winapi::ctypes::c_void, + cert_chain_context, + ) + }; + if cert_chain_context.is_null() { + break; + } + let cert_contexts = gather_cert_contexts(cert_chain_context); + // The 0th CERT_CONTEXT is the end-entity (i.e. the certificate with the private key we're + // after). + match cert_contexts.get(0) { + Some(cert_context) => { + let key = match Key::new(*cert_context) { + Ok(key) => key, + Err(_) => continue, + }; + let cert = match Cert::new(*cert_context) { + Ok(cert) => cert, + Err(_) => continue, + }; + certs.push(cert); + keys.push(key); + } + None => {} + }; + for cert_context in cert_contexts.iter().skip(1) { + if let Ok(cert) = Cert::new(*cert_context) { + certs.push(cert); + } + } + } + Ok((certs, keys)) + } +} |