1 files changed, 356 insertions, 0 deletions
diff --git a/third_party/rust/cose/examples/sign_verify/nss.rs b/third_party/rust/cose/examples/sign_verify/nss.rs
new file mode 100644
index 0000000000..a5a827ceba
--- /dev/null
+++ b/third_party/rust/cose/examples/sign_verify/nss.rs
@@ -0,0 +1,356 @@
+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,
+}
+
+// https://searchfox.org/nss/rev/990c2e793aa731cd66238c6c4f00b9473943bc66/lib/util/secoidt.h#274
+#[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)
+}