Re: [PATCH 15/17] crypto: arm/aes-ce - implement ciphertext stealing for CBC
flat view
From: Ard Biesheuvel <hidden>
Date: 2019-09-30 21:07:26
On Mon, 30 Sep 2019 at 18:32, Guenter Roeck [off-list ref] wrote:
On Wed, Aug 21, 2019 at 05:32:51PM +0300, Ard Biesheuvel wrote:quoted
Instead of relying on the CTS template to wrap the accelerated CBC skcipher, implement the ciphertext stealing part directly. Signed-off-by: Ard Biesheuvel <redacted>For arm:allmodconfig built with gcc 9.2.0, this patch results in arch/arm/crypto/aes-ce-core.S: Assembler messages: arch/arm/crypto/aes-ce-core.S:299: Error: selected processor does not support `movw ip,:lower16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:300: Error: selected processor does not support `movt ip,:upper16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:337: Error: selected processor does not support `movw ip,:lower16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:338: Error: selected processor does not support `movt ip,:upper16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:552: Error: selected processor does not support `movw ip,:lower16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:553: Error: selected processor does not support `movt ip,:upper16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:638: Error: selected processor does not support `movw ip,:lower16:.Lcts_permute_table' in ARM mode arch/arm/crypto/aes-ce-core.S:639: Error: selected processor does not support `movt ip,:upper16:.Lcts_permute_table' in ARM mode Any idea how to avoid that ?
Yes, this should fix it: https://lore.kernel.org/linux-crypto/20190917085001.792-1-ard.biesheuvel@arm.com/ (local)
quoted
--- arch/arm/crypto/aes-ce-core.S | 85 +++++++++ arch/arm/crypto/aes-ce-glue.c | 188 ++++++++++++++++++-- 2 files changed, 256 insertions(+), 17 deletions(-)diff --git a/arch/arm/crypto/aes-ce-core.S b/arch/arm/crypto/aes-ce-core.S index 763e51604ab6..b978cdf133af 100644 --- a/arch/arm/crypto/aes-ce-core.S +++ b/arch/arm/crypto/aes-ce-core.S@@ -284,6 +284,91 @@ ENTRY(ce_aes_cbc_decrypt) pop {r4-r6, pc} ENDPROC(ce_aes_cbc_decrypt) + + /* + * ce_aes_cbc_cts_encrypt(u8 out[], u8 const in[], u32 const rk[], + * int rounds, int bytes, u8 const iv[]) + * ce_aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[], + * int rounds, int bytes, u8 const iv[]) + */ + +ENTRY(ce_aes_cbc_cts_encrypt) + push {r4-r6, lr} + ldrd r4, r5, [sp, #16] + + movw ip, :lower16:.Lcts_permute_table + movt ip, :upper16:.Lcts_permute_table + sub r4, r4, #16 + add lr, ip, #32 + add ip, ip, r4 + sub lr, lr, r4 + vld1.8 {q5}, [ip] + vld1.8 {q6}, [lr] + + add ip, r1, r4 + vld1.8 {q0}, [r1] @ overlapping loads + vld1.8 {q3}, [ip] + + vld1.8 {q1}, [r5] @ get iv + prepare_key r2, r3 + + veor q0, q0, q1 @ xor with iv + bl aes_encrypt + + vtbl.8 d4, {d0-d1}, d10 + vtbl.8 d5, {d0-d1}, d11 + vtbl.8 d2, {d6-d7}, d12 + vtbl.8 d3, {d6-d7}, d13 + + veor q0, q0, q1 + bl aes_encrypt + + add r4, r0, r4 + vst1.8 {q2}, [r4] @ overlapping stores + vst1.8 {q0}, [r0] + + pop {r4-r6, pc} +ENDPROC(ce_aes_cbc_cts_encrypt) + +ENTRY(ce_aes_cbc_cts_decrypt) + push {r4-r6, lr} + ldrd r4, r5, [sp, #16] + + movw ip, :lower16:.Lcts_permute_table + movt ip, :upper16:.Lcts_permute_table + sub r4, r4, #16 + add lr, ip, #32 + add ip, ip, r4 + sub lr, lr, r4 + vld1.8 {q5}, [ip] + vld1.8 {q6}, [lr] + + add ip, r1, r4 + vld1.8 {q0}, [r1] @ overlapping loads + vld1.8 {q1}, [ip] + + vld1.8 {q3}, [r5] @ get iv + prepare_key r2, r3 + + bl aes_decrypt + + vtbl.8 d4, {d0-d1}, d10 + vtbl.8 d5, {d0-d1}, d11 + vtbx.8 d0, {d2-d3}, d12 + vtbx.8 d1, {d2-d3}, d13 + + veor q1, q1, q2 + bl aes_decrypt + veor q0, q0, q3 @ xor with iv + + add r4, r0, r4 + vst1.8 {q1}, [r4] @ overlapping stores + vst1.8 {q0}, [r0] + + pop {r4-r6, pc} +ENDPROC(ce_aes_cbc_cts_decrypt) + + /* * aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[], int rounds, * int blocks, u8 ctr[])diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c index c215792a2494..cdb1a07e7ad0 100644 --- a/arch/arm/crypto/aes-ce-glue.c +++ b/arch/arm/crypto/aes-ce-glue.c@@ -35,6 +35,10 @@ asmlinkage void ce_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[], int rounds, int blocks, u8 iv[]); asmlinkage void ce_aes_cbc_decrypt(u8 out[], u8 const in[], u32 const rk[], int rounds, int blocks, u8 iv[]); +asmlinkage void ce_aes_cbc_cts_encrypt(u8 out[], u8 const in[], u32 const rk[], + int rounds, int bytes, u8 const iv[]); +asmlinkage void ce_aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[], + int rounds, int bytes, u8 const iv[]); asmlinkage void ce_aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[], int rounds, int blocks, u8 ctr[]);@@ -210,48 +214,182 @@ static int ecb_decrypt(struct skcipher_request *req) return err; } -static int cbc_encrypt(struct skcipher_request *req) +static int cbc_encrypt_walk(struct skcipher_request *req, + struct skcipher_walk *walk) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm); - struct skcipher_walk walk; unsigned int blocks; - int err; + int err = 0; - err = skcipher_walk_virt(&walk, req, false); - - while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) { + while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) { kernel_neon_begin(); - ce_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr, + ce_aes_cbc_encrypt(walk->dst.virt.addr, walk->src.virt.addr, ctx->key_enc, num_rounds(ctx), blocks, - walk.iv); + walk->iv); kernel_neon_end(); - err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE); + err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE); } return err; } -static int cbc_decrypt(struct skcipher_request *req) +static int cbc_encrypt(struct skcipher_request *req) { - struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); - struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm); struct skcipher_walk walk; - unsigned int blocks; int err; err = skcipher_walk_virt(&walk, req, false); + if (err) + return err; + return cbc_encrypt_walk(req, &walk); +} - while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) { +static int cbc_decrypt_walk(struct skcipher_request *req, + struct skcipher_walk *walk) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm); + unsigned int blocks; + int err = 0; + + while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) { kernel_neon_begin(); - ce_aes_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr, + ce_aes_cbc_decrypt(walk->dst.virt.addr, walk->src.virt.addr, ctx->key_dec, num_rounds(ctx), blocks, - walk.iv); + walk->iv); kernel_neon_end(); - err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE); + err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE); } return err; } +static int cbc_decrypt(struct skcipher_request *req) +{ + struct skcipher_walk walk; + int err; + + err = skcipher_walk_virt(&walk, req, false); + if (err) + return err; + return cbc_decrypt_walk(req, &walk); +} + +static int cts_cbc_encrypt(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_aes_ctx *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 = skcipher_walk_virt(&walk, &subreq, false) ?: + cbc_encrypt_walk(&subreq, &walk); + 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_neon_begin(); + ce_aes_cbc_cts_encrypt(walk.dst.virt.addr, walk.src.virt.addr, + ctx->key_enc, num_rounds(ctx), walk.nbytes, + walk.iv); + kernel_neon_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 = 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 = skcipher_walk_virt(&walk, &subreq, false) ?: + cbc_decrypt_walk(&subreq, &walk); + 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_neon_begin(); + ce_aes_cbc_cts_decrypt(walk.dst.virt.addr, walk.src.virt.addr, + ctx->key_dec, num_rounds(ctx), walk.nbytes, + walk.iv); + kernel_neon_end(); + + return skcipher_walk_done(&walk, 0); +} + static int ctr_encrypt(struct skcipher_request *req) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);@@ -486,6 +624,22 @@ static struct skcipher_alg aes_algs[] = { { .setkey = ce_aes_setkey, .encrypt = cbc_encrypt, .decrypt = cbc_decrypt, +}, { + .base.cra_name = "__cts(cbc(aes))", + .base.cra_driver_name = "__cts-cbc-aes-ce", + .base.cra_priority = 300, + .base.cra_flags = CRYPTO_ALG_INTERNAL, + .base.cra_blocksize = AES_BLOCK_SIZE, + .base.cra_ctxsize = sizeof(struct crypto_aes_ctx), + .base.cra_module = THIS_MODULE, + + .min_keysize = AES_MIN_KEY_SIZE, + .max_keysize = AES_MAX_KEY_SIZE, + .ivsize = AES_BLOCK_SIZE, + .walksize = 2 * AES_BLOCK_SIZE, + .setkey = ce_aes_setkey, + .encrypt = cts_cbc_encrypt, + .decrypt = cts_cbc_decrypt, }, { .base.cra_name = "__ctr(aes)", .base.cra_driver_name = "__ctr-aes-ce",