+static int cts_cbc_encrypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_aes_ctx *ctx = aes_ctx(crypto_skcipher_ctx(tfm));
+ int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
+ struct scatterlist *src = req->src, *dst = req->dst;
+ struct scatterlist sg_src[2], sg_dst[2];
+ struct skcipher_request subreq;
+ struct skcipher_walk walk;
+ int err;
+
+ skcipher_request_set_tfm(&subreq, tfm);
+ skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
+ NULL, NULL);
+
+ if (req->cryptlen <= AES_BLOCK_SIZE) {
+ if (req->cryptlen < AES_BLOCK_SIZE)
+ return -EINVAL;
+ cbc_blocks = 1;
+ }
+
+ if (cbc_blocks > 0) {
+ skcipher_request_set_crypt(&subreq, req->src, req->dst,
+ cbc_blocks * AES_BLOCK_SIZE,
+ req->iv);
+
+ err = cbc_encrypt(&subreq);
+ if (err)
+ return err;
+
+ if (req->cryptlen == AES_BLOCK_SIZE)
+ return 0;
+
+ dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
+ if (req->dst != req->src)
+ dst = scatterwalk_ffwd(sg_dst, req->dst,
+ subreq.cryptlen);
+ }
+
+ /* handle ciphertext stealing */
+ skcipher_request_set_crypt(&subreq, src, dst,
+ req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
+ req->iv);
+
+ err = skcipher_walk_virt(&walk, &subreq, false);
+ if (err)
+ return err;
+
+ kernel_fpu_begin();
+ aesni_cts_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ walk.nbytes, walk.iv);
+ kernel_fpu_end();
+
+ return skcipher_walk_done(&walk, 0);
+}
+
+static int cts_cbc_decrypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_aes_ctx *ctx = aes_ctx(crypto_skcipher_ctx(tfm));
+ int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
+ struct scatterlist *src = req->src, *dst = req->dst;
+ struct scatterlist sg_src[2], sg_dst[2];
+ struct skcipher_request subreq;
+ struct skcipher_walk walk;
+ int err;
+
+ skcipher_request_set_tfm(&subreq, tfm);
+ skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
+ NULL, NULL);
+
+ if (req->cryptlen <= AES_BLOCK_SIZE) {
+ if (req->cryptlen < AES_BLOCK_SIZE)
+ return -EINVAL;
+ cbc_blocks = 1;
+ }
+
+ if (cbc_blocks > 0) {
+ skcipher_request_set_crypt(&subreq, req->src, req->dst,
+ cbc_blocks * AES_BLOCK_SIZE,
+ req->iv);
+
+ err = cbc_decrypt(&subreq);
+ if (err)
+ return err;
+
+ if (req->cryptlen == AES_BLOCK_SIZE)
+ return 0;
+
+ dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
+ if (req->dst != req->src)
+ dst = scatterwalk_ffwd(sg_dst, req->dst,
+ subreq.cryptlen);
+ }
+
+ /* handle ciphertext stealing */
+ skcipher_request_set_crypt(&subreq, src, dst,
+ req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
+ req->iv);
+
+ err = skcipher_walk_virt(&walk, &subreq, false);
+ if (err)
+ return err;
+
+ kernel_fpu_begin();
+ aesni_cts_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ walk.nbytes, walk.iv);
+ kernel_fpu_end();
+
+ return skcipher_walk_done(&walk, 0);
+}
+