From: Steve deRosier <ardb@xxxxxxxxxx> Add ccm(aes) implementation from linux-wireless mailing list (see http://permalink.gmane.org/gmane.linux.kernel.wireless.general/126679). This eliminates FPU context store/restore overhead existing in more general ccm_base(ctr(aes-aesni),aes-aesni) case in MAC calculation. Suggested-by: Ben Greear <greearb@xxxxxxxxxxxxxxx> Co-developed-by: Steve deRosier <derosier@xxxxxxxxxxxxxx> Signed-off-by: Steve deRosier <derosier@xxxxxxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- Ben, This is almost a rewrite of the original patch, switching to the new skcipher API, using the existing SIMD helper, and drop numerous unrelated changes. The basic approach is almost identical, though, so I expect this to perform on par or perhaps slightly faster than the original. Could you please confirm with some numbers? Thanks, Ard. arch/x86/crypto/aesni-intel_glue.c | 310 ++++++++++++++++++++ 1 file changed, 310 insertions(+) diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c index ad8a7188a2bf..f59f3c8772a6 100644 --- a/arch/x86/crypto/aesni-intel_glue.c +++ b/arch/x86/crypto/aesni-intel_glue.c @@ -513,6 +513,298 @@ static int ctr_crypt(struct skcipher_request *req) return err; } +static int aesni_ccm_setkey(struct crypto_aead *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct crypto_aes_ctx *ctx = crypto_aead_ctx(tfm); + + return aes_set_key_common(crypto_aead_tfm(tfm), ctx, in_key, key_len); +} + +static int aesni_ccm_setauthsize(struct crypto_aead *tfm, unsigned int authsize) +{ + if ((authsize & 1) || authsize < 4) + return -EINVAL; + return 0; +} + +static int ccm_set_msg_len(u8 *block, unsigned int msglen, int csize) +{ + __be32 data; + + memset(block, 0, csize); + block += csize; + + if (csize >= 4) + csize = 4; + else if (msglen > (1 << (8 * csize))) + return -EOVERFLOW; + + data = cpu_to_be32(msglen); + memcpy(block - csize, (u8 *)&data + 4 - csize, csize); + + return 0; +} + +static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + __be32 *n = (__be32 *)&maciv[AES_BLOCK_SIZE - 8]; + u32 l = req->iv[0] + 1; + + /* verify that CCM dimension 'L' is set correctly in the IV */ + if (l < 2 || l > 8) + return -EINVAL; + + /* verify that msglen can in fact be represented in L bytes */ + if (l < 4 && msglen >> (8 * l)) + return -EOVERFLOW; + + /* + * Even if the CCM spec allows L values of up to 8, the Linux cryptoapi + * uses a u32 type to represent msglen so the top 4 bytes are always 0. + */ + n[0] = 0; + n[1] = cpu_to_be32(msglen); + + memcpy(maciv, req->iv, AES_BLOCK_SIZE - l); + + /* + * Meaning of byte 0 according to CCM spec (RFC 3610/NIST 800-38C) + * - bits 0..2 : max # of bytes required to represent msglen, minus 1 + * (already set by caller) + * - bits 3..5 : size of auth tag (1 => 4 bytes, 2 => 6 bytes, etc) + * - bit 6 : indicates presence of authenticate-only data + */ + maciv[0] |= (crypto_aead_authsize(aead) - 2) << 2; + if (req->assoclen) + maciv[0] |= 0x40; + + memset(&req->iv[AES_BLOCK_SIZE - l], 0, l); + return ccm_set_msg_len(maciv + AES_BLOCK_SIZE - l, msglen, l); +} + +static int compute_mac(struct crypto_aes_ctx *ctx, u8 mac[], u8 *data, int n, + unsigned int ilen, u8 *idata) +{ + unsigned int bs = AES_BLOCK_SIZE; + u8 *odata = mac; + int datalen, getlen; + + datalen = n; + + /* first time in here, block may be partially filled. */ + getlen = bs - ilen; + if (datalen >= getlen) { + memcpy(idata + ilen, data, getlen); + + aesni_cbc_enc(ctx, odata, idata, AES_BLOCK_SIZE, odata); + + datalen -= getlen; + data += getlen; + ilen = 0; + } + + /* now encrypt rest of data */ + while (datalen >= bs) { + aesni_cbc_enc(ctx, odata, data, AES_BLOCK_SIZE, odata); + + datalen -= bs; + data += bs; + } + + /* check and see if there's leftover data that wasn't + * enough to fill a block. + */ + if (datalen) { + memcpy(idata + ilen, data, datalen); + ilen += datalen; + } + return ilen; +} + +static void ccm_calculate_auth_mac(struct aead_request *req, + struct crypto_aes_ctx *ctx, u8 mac[], + struct scatterlist *src) +{ + unsigned int len = req->assoclen; + struct scatter_walk walk; + u8 idata[AES_BLOCK_SIZE]; + unsigned int ilen; + struct { + __be16 l; + __be32 h; + } __packed *ltag = (void *)idata; + + /* prepend the AAD with a length tag */ + if (len < 0xff00) { + ltag->l = cpu_to_be16(len); + ilen = 2; + } else { + ltag->l = cpu_to_be16(0xfffe); + ltag->h = cpu_to_be32(len); + ilen = 6; + } + + scatterwalk_start(&walk, src); + + while (len) { + u8 *src; + int n; + + n = scatterwalk_clamp(&walk, len); + if (!n) { + scatterwalk_start(&walk, sg_next(walk.sg)); + n = scatterwalk_clamp(&walk, len); + } + src = scatterwalk_map(&walk); + + ilen = compute_mac(ctx, mac, src, n, ilen, idata); + len -= n; + + scatterwalk_unmap(src); + scatterwalk_advance(&walk, n); + scatterwalk_done(&walk, 0, len); + } + + /* any leftover needs padding and then encrypted */ + if (ilen) { + crypto_xor(mac, idata, ilen); + aesni_enc(ctx, mac, mac); + } +} + +static int aesni_ccm_encrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct crypto_aes_ctx *ctx = aes_ctx(crypto_aead_ctx(aead)); + u8 __aligned(8) mac[AES_BLOCK_SIZE]; + struct skcipher_walk walk; + u32 l = req->iv[0] + 1; + int err; + + err = ccm_init_mac(req, mac, req->cryptlen); + if (err) + return err; + + kernel_fpu_begin(); + + aesni_enc(ctx, mac, mac); + + if (req->assoclen) + ccm_calculate_auth_mac(req, ctx, mac, req->src); + + req->iv[AES_BLOCK_SIZE - 1] = 0x1; + err = skcipher_walk_aead_encrypt(&walk, req, true); + + while (walk.nbytes >= AES_BLOCK_SIZE) { + int len = walk.nbytes & AES_BLOCK_MASK; + int n; + + for (n = 0; n < len; n += AES_BLOCK_SIZE) + aesni_cbc_enc(ctx, mac, walk.src.virt.addr + n, + AES_BLOCK_SIZE, mac); + + aesni_ctr_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr, len, + walk.iv); + + err = skcipher_walk_done(&walk, walk.nbytes & ~AES_BLOCK_MASK); + } + if (walk.nbytes) { + u8 __aligned(8) buf[AES_BLOCK_SIZE] = {}; + + memcpy(buf, walk.src.virt.addr, walk.nbytes); + aesni_cbc_enc(ctx, mac, buf, AES_BLOCK_SIZE, mac); + + ctr_crypt_final(ctx, &walk); + + err = skcipher_walk_done(&walk, 0); + } + + if (err) + goto fail; + + memset(walk.iv + AES_BLOCK_SIZE - l, 0, l); + aesni_ctr_enc(ctx, mac, mac, AES_BLOCK_SIZE, walk.iv); + + /* copy authtag to end of dst */ + scatterwalk_map_and_copy(mac, req->dst, req->assoclen + req->cryptlen, + crypto_aead_authsize(aead), 1); + +fail: + kernel_fpu_end(); + return err; +} + +static int aesni_ccm_decrypt(struct aead_request *req) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct crypto_aes_ctx *ctx = aes_ctx(crypto_aead_ctx(aead)); + unsigned int authsize = crypto_aead_authsize(aead); + u8 __aligned(8) mac[AES_BLOCK_SIZE]; + u8 __aligned(8) tag[AES_BLOCK_SIZE]; + struct skcipher_walk walk; + u32 l = req->iv[0] + 1; + int err; + + err = ccm_init_mac(req, mac, req->cryptlen - authsize); + if (err) + return err; + + /* copy authtag from end of src */ + scatterwalk_map_and_copy(tag, req->src, + req->assoclen + req->cryptlen - authsize, + authsize, 0); + + kernel_fpu_begin(); + + aesni_enc(ctx, mac, mac); + + if (req->assoclen) + ccm_calculate_auth_mac(req, ctx, mac, req->src); + + req->iv[AES_BLOCK_SIZE - 1] = 0x1; + err = skcipher_walk_aead_decrypt(&walk, req, true); + + while (walk.nbytes >= AES_BLOCK_SIZE) { + int len = walk.nbytes & AES_BLOCK_MASK; + int n; + + aesni_ctr_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr, len, + walk.iv); + + for (n = 0; n < len; n += AES_BLOCK_SIZE) + aesni_cbc_enc(ctx, mac, walk.dst.virt.addr + n, + AES_BLOCK_SIZE, mac); + + err = skcipher_walk_done(&walk, walk.nbytes & ~AES_BLOCK_MASK); + } + if (walk.nbytes) { + u8 __aligned(8) buf[AES_BLOCK_SIZE] = {}; + + ctr_crypt_final(ctx, &walk); + + memcpy(buf, walk.dst.virt.addr, walk.nbytes); + aesni_cbc_enc(ctx, mac, buf, AES_BLOCK_SIZE, mac); + + err = skcipher_walk_done(&walk, 0); + } + + if (err) + goto fail; + + memset(walk.iv + AES_BLOCK_SIZE - l, 0, l); + aesni_ctr_enc(ctx, mac, mac, AES_BLOCK_SIZE, walk.iv); + + /* compare calculated auth tag with the stored one */ + if (crypto_memneq(mac, tag, authsize)) + err = -EBADMSG; + +fail: + kernel_fpu_end(); + return err; +} + static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned int keylen) { @@ -1044,6 +1336,24 @@ static struct aead_alg aesni_aeads[] = { { .cra_alignmask = AESNI_ALIGN - 1, .cra_module = THIS_MODULE, }, +}, { + .setkey = aesni_ccm_setkey, + .setauthsize = aesni_ccm_setauthsize, + .encrypt = aesni_ccm_encrypt, + .decrypt = aesni_ccm_decrypt, + .ivsize = AES_BLOCK_SIZE, + .chunksize = AES_BLOCK_SIZE, + .maxauthsize = AES_BLOCK_SIZE, + .base = { + .cra_name = "__ccm(aes)", + .cra_driver_name = "__ccm-aesni", + .cra_priority = 400, + .cra_flags = CRYPTO_ALG_INTERNAL, + .cra_blocksize = 1, + .cra_ctxsize = sizeof(struct crypto_aes_ctx), + .cra_alignmask = AESNI_ALIGN - 1, + .cra_module = THIS_MODULE, + }, } }; #else static struct aead_alg aesni_aeads[0]; -- 2.17.1
