Merge pull request #1762 from wiktor-k/fix-broken-relaxation (f0ff8a7e) · Commits · Public Repositories / Rust Openssl

openssl/src/cipher_ctx.rs

+37 −152

Original line number	Diff line number	Diff line
		@@ -379,49 +379,6 @@ impl CipherCtxRef {
		unsafe { ffi::EVP_CIPHER_CTX_num(self.as_ptr()) as usize }
		}

		/// Returns number of bytes cached in partial block update.
		#[cfg(ossl110)]
		fn used_block_size(&self) -> usize {
		self.num()
		}

		/// Returns maximum number of bytes that could be cached.
		#[cfg(not(ossl110))]
		fn used_block_size(&self) -> usize {
		self.block_size()
		}

		/// Calculate the minimal size of the output buffer given the
		/// input buffer size.
		///
		/// For streaming ciphers the minimal output size is the same as
		/// the input size. For block ciphers the minimal output size
		/// additionally depends on the partial blocks that might have
		/// been written in previous calls to [`Self::cipher_update`].
		///
		/// This function takes into account the number of partially
		/// written blocks for block ciphers for supported targets
		/// (OpenSSL >= 1.1). For unsupported targets the number of
		/// partially written bytes is assumed to contain one full block
		/// (pessimistic case).
		///
		/// # Panics
		///
		/// Panics if the context has not been initialized with a cipher.
		pub fn minimal_output_size(&self, inlen: usize) -> usize {
		let block_size = self.block_size();
		if block_size > 1 {
		// block cipher
		let num = self.used_block_size();
		let total_size = inlen + num;
		let num_blocks = total_size / block_size;
		num_blocks * block_size
		} else {
		// streaming cipher
		inlen
		}
		}

		/// Sets the length of the IV expected by this context.
		///
		/// Only some ciphers support configurable IV lengths.
		@@ -569,7 +526,11 @@ impl CipherCtxRef {
		output: Option<&mut [u8]>,
		) -> Result<usize, ErrorStack> {
		if let Some(output) = &output {
		let min_output_size = self.minimal_output_size(input.len());
		let mut block_size = self.block_size();
		if block_size == 1 {
		block_size = 0;
		}
		let min_output_size = input.len() + block_size;
		assert!(
		output.len() >= min_output_size,
		"Output buffer size should be at least {} bytes.",
		@@ -588,16 +549,13 @@ impl CipherCtxRef {
		///
		/// This function is the same as [`Self::cipher_update`] but with the
		/// output size check removed. It can be used when the exact
		/// buffer size control is maintained by the caller and the
		/// underlying cryptographic library doesn't expose exact block
		/// cache data (e.g. OpenSSL < 1.1, BoringSSL, LibreSSL).
		/// buffer size control is maintained by the caller.
		///
		/// SAFETY: The caller is expected to provide `output` buffer
		/// large enough to contain correct number of bytes. For streaming
		/// ciphers the output buffer size should be at least as big as
		/// the input buffer. For block ciphers the size of the output
		/// buffer depends on the state of partially updated blocks (see
		/// [`Self::minimal_output_size`]).
		/// buffer depends on the state of partially updated blocks.
		#[corresponds(EVP_CipherUpdate)]
		pub unsafe fn cipher_update_unchecked(
		&mut self,
		@@ -649,14 +607,34 @@ impl CipherCtxRef {
		assert!(output.len() >= block_size);
		}

		unsafe { self.cipher_final_unchecked(output) }
		}

		/// Finalizes the encryption or decryption process.
		///
		/// Any remaining data will be written to the output buffer.
		///
		/// Returns the number of bytes written to `output`.
		///
		/// This function is the same as [`Self::cipher_final`] but with
		/// the output buffer size check removed.
		///
		/// SAFETY: The caller is expected to provide `output` buffer
		/// large enough to contain correct number of bytes. For streaming
		/// ciphers the output buffer can be empty, for block ciphers the
		/// output buffer should be at least as big as the block.
		#[corresponds(EVP_CipherFinal)]
		pub unsafe fn cipher_final_unchecked(
		&mut self,
		output: &mut [u8],
		) -> Result<usize, ErrorStack> {
		let mut outl = 0;
		unsafe {

		cvt(ffi::EVP_CipherFinal(
		self.as_ptr(),
		output.as_mut_ptr(),
		&mut outl,
		))?;
		}

		Ok(outl as usize)
		}
		@@ -757,75 +735,6 @@ mod test {
		aes_128_cbc(cipher);
		}

		#[test]
		#[cfg(ossl110)]
		fn partial_block_updates() {
		test_block_cipher_for_partial_block_updates(Cipher::aes_128_cbc());
		test_block_cipher_for_partial_block_updates(Cipher::aes_256_cbc());
		test_block_cipher_for_partial_block_updates(Cipher::des_ede3_cbc());
		}

		#[cfg(ossl110)]
		fn test_block_cipher_for_partial_block_updates(cipher: &'static CipherRef) {
		let mut key = vec![0; cipher.key_length()];
		rand_bytes(&mut key).unwrap();
		let mut iv = vec![0; cipher.iv_length()];
		rand_bytes(&mut iv).unwrap();

		let mut ctx = CipherCtx::new().unwrap();

		ctx.encrypt_init(Some(cipher), Some(&key), Some(&iv))
		.unwrap();
		ctx.set_padding(false);

		let block_size = cipher.block_size();
		assert!(block_size > 1, "Need a block cipher, not a stream cipher");

		// update cipher with non-full block
		// expect no output until a block is complete
		let outlen = ctx
		.cipher_update(&vec![0; block_size - 1], Some(&mut [0; 0]))
		.unwrap();
		assert_eq!(0, outlen);

		// update cipher with missing bytes from the previous block
		// and one additional block, output should contain two blocks
		let mut two_blocks = vec![0; block_size * 2];
		let outlen = ctx
		.cipher_update(&vec![0; block_size + 1], Some(&mut two_blocks))
		.unwrap();
		assert_eq!(block_size * 2, outlen);

		ctx.cipher_final_vec(&mut vec![0; 0]).unwrap();

		// try to decrypt
		ctx.decrypt_init(Some(cipher), Some(&key), Some(&iv))
		.unwrap();
		ctx.set_padding(false);

		// update cipher with non-full block
		// expect no output until a block is complete
		let outlen = ctx
		.cipher_update(&two_blocks[0..block_size - 1], Some(&mut [0; 0]))
		.unwrap();
		assert_eq!(0, outlen);

		// update cipher with missing bytes from the previous block
		// and one additional block, output should contain two blocks
		let mut two_blocks_decrypted = vec![0; block_size * 2];
		let outlen = ctx
		.cipher_update(
		&two_blocks[block_size - 1..],
		Some(&mut two_blocks_decrypted),
		)
		.unwrap();
		assert_eq!(block_size * 2, outlen);

		ctx.cipher_final_vec(&mut vec![0; 0]).unwrap();
		// check if the decrypted blocks are the same as input (all zeros)
		assert_eq!(two_blocks_decrypted, vec![0; block_size * 2]);
		}

		#[test]
		fn test_stream_ciphers() {
		test_stream_cipher(Cipher::aes_192_ctr());
		@@ -894,43 +803,19 @@ mod test {
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 16 bytes.")]
		#[cfg(ossl110)]
		fn full_block_updates_aes_128() {
		output_buffer_too_small(Cipher::aes_128_cbc());
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 16 bytes.")]
		#[cfg(ossl110)]
		fn full_block_updates_aes_256() {
		output_buffer_too_small(Cipher::aes_256_cbc());
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 8 bytes.")]
		#[cfg(ossl110)]
		fn full_block_updates_3des() {
		output_buffer_too_small(Cipher::des_ede3_cbc());
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 32 bytes.")]
		#[cfg(not(ossl110))]
		#[should_panic(expected = "Output buffer size should be at least 33 bytes.")]
		fn full_block_updates_aes_128() {
		output_buffer_too_small(Cipher::aes_128_cbc());
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 32 bytes.")]
		#[cfg(not(ossl110))]
		#[should_panic(expected = "Output buffer size should be at least 33 bytes.")]
		fn full_block_updates_aes_256() {
		output_buffer_too_small(Cipher::aes_256_cbc());
		}

		#[test]
		#[should_panic(expected = "Output buffer size should be at least 16 bytes.")]
		#[cfg(not(ossl110))]
		#[should_panic(expected = "Output buffer size should be at least 17 bytes.")]
		fn full_block_updates_3des() {
		output_buffer_too_small(Cipher::des_ede3_cbc());
		}