From 83c83e658863e4e57f4defe6cc1bc05f3d968e2a Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 4 Jan 2021 16:55:49 +0100 Subject: [PATCH] crypto: aesni - refactor scatterlist processing Currently, the gcm(aes-ni) driver open codes the scatterlist handling that is encapsulated by the skcipher walk API. So let's switch to that instead. Also, move the handling at the end of gcmaes_crypt_by_sg() that is dependent on whether we are encrypting or decrypting into the callers, which always do one or the other. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/x86/crypto/aesni-intel_glue.c | 139 +++++++++++++++---------------------- 1 file changed, 56 insertions(+), 83 deletions(-) diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c index efef6e6b1d34..180fa79a0727 100644 --- a/arch/x86/crypto/aesni-intel_glue.c +++ b/arch/x86/crypto/aesni-intel_glue.c @@ -638,25 +638,18 @@ static int generic_gcmaes_set_authsize(struct crypto_aead *tfm, static int gcmaes_crypt_by_sg(bool enc, struct aead_request *req, unsigned int assoclen, u8 *hash_subkey, - u8 *iv, void *aes_ctx) + u8 *iv, void *aes_ctx, u8 *auth_tag, + unsigned long auth_tag_len) { - struct crypto_aead *tfm = crypto_aead_reqtfm(req); - unsigned long auth_tag_len = crypto_aead_authsize(tfm); const struct aesni_gcm_tfm_s *gcm_tfm = aesni_gcm_tfm; u8 databuf[sizeof(struct gcm_context_data) + (AESNI_ALIGN - 8)] __aligned(8); struct gcm_context_data *data = PTR_ALIGN((void *)databuf, AESNI_ALIGN); - struct scatter_walk dst_sg_walk = {}; unsigned long left = req->cryptlen; - unsigned long len, srclen, dstlen; struct scatter_walk assoc_sg_walk; - struct scatter_walk src_sg_walk; - struct scatterlist src_start[2]; - struct scatterlist dst_start[2]; - struct scatterlist *src_sg; - struct scatterlist *dst_sg; - u8 *src, *dst, *assoc; + struct skcipher_walk walk; u8 *assocmem = NULL; - u8 authTag[16]; + u8 *assoc; + int err; if (!enc) left -= auth_tag_len; @@ -683,61 +676,8 @@ static int gcmaes_crypt_by_sg(bool enc, struct aead_request *req, scatterwalk_map_and_copy(assoc, req->src, 0, assoclen, 0); } - if (left) { - src_sg = scatterwalk_ffwd(src_start, req->src, req->assoclen); - scatterwalk_start(&src_sg_walk, src_sg); - if (req->src != req->dst) { - dst_sg = scatterwalk_ffwd(dst_start, req->dst, - req->assoclen); - scatterwalk_start(&dst_sg_walk, dst_sg); - } - } - kernel_fpu_begin(); gcm_tfm->init(aes_ctx, data, iv, hash_subkey, assoc, assoclen); - if (req->src != req->dst) { - while (left) { - src = scatterwalk_map(&src_sg_walk); - dst = scatterwalk_map(&dst_sg_walk); - srclen = scatterwalk_clamp(&src_sg_walk, left); - dstlen = scatterwalk_clamp(&dst_sg_walk, left); - len = min(srclen, dstlen); - if (len) { - if (enc) - gcm_tfm->enc_update(aes_ctx, data, - dst, src, len); - else - gcm_tfm->dec_update(aes_ctx, data, - dst, src, len); - } - left -= len; - - scatterwalk_unmap(src); - scatterwalk_unmap(dst); - scatterwalk_advance(&src_sg_walk, len); - scatterwalk_advance(&dst_sg_walk, len); - scatterwalk_done(&src_sg_walk, 0, left); - scatterwalk_done(&dst_sg_walk, 1, left); - } - } else { - while (left) { - dst = src = scatterwalk_map(&src_sg_walk); - len = scatterwalk_clamp(&src_sg_walk, left); - if (len) { - if (enc) - gcm_tfm->enc_update(aes_ctx, data, - src, src, len); - else - gcm_tfm->dec_update(aes_ctx, data, - src, src, len); - } - left -= len; - scatterwalk_unmap(src); - scatterwalk_advance(&src_sg_walk, len); - scatterwalk_done(&src_sg_walk, 1, left); - } - } - gcm_tfm->finalize(aes_ctx, data, authTag, auth_tag_len); kernel_fpu_end(); if (!assocmem) @@ -745,24 +685,25 @@ static int gcmaes_crypt_by_sg(bool enc, struct aead_request *req, else kfree(assocmem); - if (!enc) { - u8 authTagMsg[16]; + err = enc ? skcipher_walk_aead_encrypt(&walk, req, false) + : skcipher_walk_aead_decrypt(&walk, req, false); - /* Copy out original authTag */ - scatterwalk_map_and_copy(authTagMsg, req->src, - req->assoclen + req->cryptlen - - auth_tag_len, - auth_tag_len, 0); + while (walk.nbytes > 0) { + kernel_fpu_begin(); + (enc ? gcm_tfm->enc_update + : gcm_tfm->dec_update)(aes_ctx, data, walk.dst.virt.addr, + walk.src.virt.addr, walk.nbytes); + kernel_fpu_end(); - /* Compare generated tag with passed in tag. */ - return crypto_memneq(authTagMsg, authTag, auth_tag_len) ? - -EBADMSG : 0; + err = skcipher_walk_done(&walk, 0); } - /* Copy in the authTag */ - scatterwalk_map_and_copy(authTag, req->dst, - req->assoclen + req->cryptlen, - auth_tag_len, 1); + if (err) + return err; + + kernel_fpu_begin(); + gcm_tfm->finalize(aes_ctx, data, auth_tag, auth_tag_len); + kernel_fpu_end(); return 0; } @@ -770,15 +711,47 @@ static int gcmaes_crypt_by_sg(bool enc, struct aead_request *req, static int gcmaes_encrypt(struct aead_request *req, unsigned int assoclen, u8 *hash_subkey, u8 *iv, void *aes_ctx) { - return gcmaes_crypt_by_sg(true, req, assoclen, hash_subkey, iv, - aes_ctx); + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + unsigned long auth_tag_len = crypto_aead_authsize(tfm); + u8 auth_tag[16]; + int err; + + err = gcmaes_crypt_by_sg(true, req, assoclen, hash_subkey, iv, aes_ctx, + auth_tag, auth_tag_len); + if (err) + return err; + + scatterwalk_map_and_copy(auth_tag, req->dst, + req->assoclen + req->cryptlen, + auth_tag_len, 1); + return 0; } static int gcmaes_decrypt(struct aead_request *req, unsigned int assoclen, u8 *hash_subkey, u8 *iv, void *aes_ctx) { - return gcmaes_crypt_by_sg(false, req, assoclen, hash_subkey, iv, - aes_ctx); + struct crypto_aead *tfm = crypto_aead_reqtfm(req); + unsigned long auth_tag_len = crypto_aead_authsize(tfm); + u8 auth_tag_msg[16]; + u8 auth_tag[16]; + int err; + + err = gcmaes_crypt_by_sg(false, req, assoclen, hash_subkey, iv, aes_ctx, + auth_tag, auth_tag_len); + if (err) + return err; + + /* Copy out original auth_tag */ + scatterwalk_map_and_copy(auth_tag_msg, req->src, + req->assoclen + req->cryptlen - auth_tag_len, + auth_tag_len, 0); + + /* Compare generated tag with passed in tag. */ + if (crypto_memneq(auth_tag_msg, auth_tag, auth_tag_len)) { + memzero_explicit(auth_tag, sizeof(auth_tag)); + return -EBADMSG; + } + return 0; } static int helper_rfc4106_encrypt(struct aead_request *req) -- 2.11.0