From d95312a3ccc0cd544d374be2fc45aeaa803e5fd9 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 8 Nov 2019 13:22:40 +0100 Subject: crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine Reimplement the library routines to perform chacha20poly1305 en/decryption on scatterlists, without [ab]using the [deprecated] blkcipher interface, which is rather heavyweight and does things we don't really need. Instead, we use the sg_miter API in a novel and clever way, to iterate over the scatterlist in-place (i.e., source == destination, which is the only way this library is expected to be used). That way, we don't have to iterate over two scatterlists in parallel. Another optimization is that, instead of relying on the blkcipher walker to present the input in suitable chunks, we recognize that ChaCha is a streamcipher, and so we can simply deal with partial blocks by keeping a block of cipherstream on the stack and use crypto_xor() to mix it with the in/output. Finally, we omit the scatterwalk_and_copy() call if the last element of the scatterlist covers the MAC as well (which is the common case), avoiding the need to walk the scatterlist and kmap() the page twice. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- lib/crypto/chacha20poly1305-selftest.c | 45 ++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'lib/crypto/chacha20poly1305-selftest.c') diff --git a/lib/crypto/chacha20poly1305-selftest.c b/lib/crypto/chacha20poly1305-selftest.c index d1ed0f27cfdb..465de46dbdef 100644 --- a/lib/crypto/chacha20poly1305-selftest.c +++ b/lib/crypto/chacha20poly1305-selftest.c @@ -7250,6 +7250,7 @@ bool __init chacha20poly1305_selftest(void) enum { MAXIMUM_TEST_BUFFER_LEN = 1UL << 12 }; size_t i; u8 *computed_output = NULL, *heap_src = NULL; + struct scatterlist sg_src; bool success = true, ret; heap_src = kmalloc(MAXIMUM_TEST_BUFFER_LEN, GFP_KERNEL); @@ -7280,6 +7281,29 @@ bool __init chacha20poly1305_selftest(void) } } + for (i = 0; i < ARRAY_SIZE(chacha20poly1305_enc_vectors); ++i) { + if (chacha20poly1305_enc_vectors[i].nlen != 8) + continue; + memcpy(heap_src, chacha20poly1305_enc_vectors[i].input, + chacha20poly1305_enc_vectors[i].ilen); + sg_init_one(&sg_src, heap_src, + chacha20poly1305_enc_vectors[i].ilen + POLY1305_DIGEST_SIZE); + chacha20poly1305_encrypt_sg_inplace(&sg_src, + chacha20poly1305_enc_vectors[i].ilen, + chacha20poly1305_enc_vectors[i].assoc, + chacha20poly1305_enc_vectors[i].alen, + get_unaligned_le64(chacha20poly1305_enc_vectors[i].nonce), + chacha20poly1305_enc_vectors[i].key); + if (memcmp(heap_src, + chacha20poly1305_enc_vectors[i].output, + chacha20poly1305_enc_vectors[i].ilen + + POLY1305_DIGEST_SIZE)) { + pr_err("chacha20poly1305 sg encryption self-test %zu: FAIL\n", + i + 1); + success = false; + } + } + for (i = 0; i < ARRAY_SIZE(chacha20poly1305_dec_vectors); ++i) { memset(computed_output, 0, MAXIMUM_TEST_BUFFER_LEN); ret = chacha20poly1305_decrypt(computed_output, @@ -7301,6 +7325,27 @@ bool __init chacha20poly1305_selftest(void) } } + for (i = 0; i < ARRAY_SIZE(chacha20poly1305_dec_vectors); ++i) { + memcpy(heap_src, chacha20poly1305_dec_vectors[i].input, + chacha20poly1305_dec_vectors[i].ilen); + sg_init_one(&sg_src, heap_src, + chacha20poly1305_dec_vectors[i].ilen); + ret = chacha20poly1305_decrypt_sg_inplace(&sg_src, + chacha20poly1305_dec_vectors[i].ilen, + chacha20poly1305_dec_vectors[i].assoc, + chacha20poly1305_dec_vectors[i].alen, + get_unaligned_le64(chacha20poly1305_dec_vectors[i].nonce), + chacha20poly1305_dec_vectors[i].key); + if (!decryption_success(ret, + chacha20poly1305_dec_vectors[i].failure, + memcmp(heap_src, chacha20poly1305_dec_vectors[i].output, + chacha20poly1305_dec_vectors[i].ilen - + POLY1305_DIGEST_SIZE))) { + pr_err("chacha20poly1305 sg decryption self-test %zu: FAIL\n", + i + 1); + success = false; + } + } for (i = 0; i < ARRAY_SIZE(xchacha20poly1305_enc_vectors); ++i) { memset(computed_output, 0, MAXIMUM_TEST_BUFFER_LEN); -- cgit v1.2.3