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https://github.com/torvalds/linux
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crypto: aesni - implement support for cts(cbc(aes))
Follow the same approach as the arm64 driver for implementing a version of AES-NI in CBC mode that supports ciphertext stealing. This results in a ~2x speed increase for relatively short inputs (less than 256 bytes), which is relevant given that AES-CBC with ciphertext stealing is used for filename encryption in the fscrypt layer. For larger inputs, the speedup is still significant (~25% on decryption, ~6% on encryption) Tested-by: Eric Biggers <ebiggers@google.com> # x86_64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel
Herbert Xu
parent
a417178abc
commit
ddf169a98f
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@ -2577,13 +2577,140 @@ SYM_FUNC_START(aesni_cbc_dec)
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ret
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SYM_FUNC_END(aesni_cbc_dec)
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#ifdef __x86_64__
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/*
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* void aesni_cts_cbc_enc(struct crypto_aes_ctx *ctx, const u8 *dst, u8 *src,
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* size_t len, u8 *iv)
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*/
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SYM_FUNC_START(aesni_cts_cbc_enc)
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FRAME_BEGIN
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#ifndef __x86_64__
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pushl IVP
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pushl LEN
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pushl KEYP
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pushl KLEN
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movl (FRAME_OFFSET+20)(%esp), KEYP # ctx
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movl (FRAME_OFFSET+24)(%esp), OUTP # dst
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movl (FRAME_OFFSET+28)(%esp), INP # src
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movl (FRAME_OFFSET+32)(%esp), LEN # len
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movl (FRAME_OFFSET+36)(%esp), IVP # iv
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lea .Lcts_permute_table, T1
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#else
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lea .Lcts_permute_table(%rip), T1
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#endif
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mov 480(KEYP), KLEN
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movups (IVP), STATE
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sub $16, LEN
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mov T1, IVP
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add $32, IVP
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add LEN, T1
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sub LEN, IVP
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movups (T1), %xmm4
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movups (IVP), %xmm5
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movups (INP), IN1
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add LEN, INP
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movups (INP), IN2
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pxor IN1, STATE
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call _aesni_enc1
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pshufb %xmm5, IN2
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pxor STATE, IN2
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pshufb %xmm4, STATE
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add OUTP, LEN
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movups STATE, (LEN)
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movaps IN2, STATE
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call _aesni_enc1
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movups STATE, (OUTP)
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#ifndef __x86_64__
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popl KLEN
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popl KEYP
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popl LEN
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popl IVP
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#endif
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FRAME_END
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ret
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SYM_FUNC_END(aesni_cts_cbc_enc)
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/*
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* void aesni_cts_cbc_dec(struct crypto_aes_ctx *ctx, const u8 *dst, u8 *src,
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* size_t len, u8 *iv)
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*/
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SYM_FUNC_START(aesni_cts_cbc_dec)
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FRAME_BEGIN
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#ifndef __x86_64__
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pushl IVP
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pushl LEN
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pushl KEYP
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pushl KLEN
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movl (FRAME_OFFSET+20)(%esp), KEYP # ctx
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movl (FRAME_OFFSET+24)(%esp), OUTP # dst
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movl (FRAME_OFFSET+28)(%esp), INP # src
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movl (FRAME_OFFSET+32)(%esp), LEN # len
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movl (FRAME_OFFSET+36)(%esp), IVP # iv
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lea .Lcts_permute_table, T1
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#else
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lea .Lcts_permute_table(%rip), T1
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#endif
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mov 480(KEYP), KLEN
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add $240, KEYP
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movups (IVP), IV
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sub $16, LEN
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mov T1, IVP
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add $32, IVP
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add LEN, T1
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sub LEN, IVP
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movups (T1), %xmm4
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movups (INP), STATE
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add LEN, INP
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movups (INP), IN1
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call _aesni_dec1
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movaps STATE, IN2
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pshufb %xmm4, STATE
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pxor IN1, STATE
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add OUTP, LEN
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movups STATE, (LEN)
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movups (IVP), %xmm0
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pshufb %xmm0, IN1
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pblendvb IN2, IN1
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movaps IN1, STATE
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call _aesni_dec1
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pxor IV, STATE
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movups STATE, (OUTP)
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#ifndef __x86_64__
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popl KLEN
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popl KEYP
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popl LEN
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popl IVP
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#endif
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FRAME_END
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ret
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SYM_FUNC_END(aesni_cts_cbc_dec)
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.pushsection .rodata
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.align 16
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.Lcts_permute_table:
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.byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
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.byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
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.byte 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07
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.byte 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
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.byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
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.byte 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80
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#ifdef __x86_64__
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.Lbswap_mask:
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.byte 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
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#endif
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.popsection
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#ifdef __x86_64__
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/*
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* _aesni_inc_init: internal ABI
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* setup registers used by _aesni_inc
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@ -93,6 +93,10 @@ asmlinkage void aesni_cbc_enc(struct crypto_aes_ctx *ctx, u8 *out,
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const u8 *in, unsigned int len, u8 *iv);
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asmlinkage void aesni_cbc_dec(struct crypto_aes_ctx *ctx, u8 *out,
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const u8 *in, unsigned int len, u8 *iv);
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asmlinkage void aesni_cts_cbc_enc(struct crypto_aes_ctx *ctx, u8 *out,
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const u8 *in, unsigned int len, u8 *iv);
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asmlinkage void aesni_cts_cbc_dec(struct crypto_aes_ctx *ctx, u8 *out,
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const u8 *in, unsigned int len, u8 *iv);
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#define AVX_GEN2_OPTSIZE 640
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#define AVX_GEN4_OPTSIZE 4096
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@ -454,6 +458,118 @@ static int cbc_decrypt(struct skcipher_request *req)
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return err;
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}
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static int cts_cbc_encrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct crypto_aes_ctx *ctx = aes_ctx(crypto_skcipher_ctx(tfm));
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int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
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struct scatterlist *src = req->src, *dst = req->dst;
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struct scatterlist sg_src[2], sg_dst[2];
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struct skcipher_request subreq;
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struct skcipher_walk walk;
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int err;
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skcipher_request_set_tfm(&subreq, tfm);
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skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
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NULL, NULL);
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if (req->cryptlen <= AES_BLOCK_SIZE) {
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if (req->cryptlen < AES_BLOCK_SIZE)
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return -EINVAL;
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cbc_blocks = 1;
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}
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if (cbc_blocks > 0) {
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skcipher_request_set_crypt(&subreq, req->src, req->dst,
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cbc_blocks * AES_BLOCK_SIZE,
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req->iv);
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err = cbc_encrypt(&subreq);
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if (err)
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return err;
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if (req->cryptlen == AES_BLOCK_SIZE)
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return 0;
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dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
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if (req->dst != req->src)
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dst = scatterwalk_ffwd(sg_dst, req->dst,
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subreq.cryptlen);
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}
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/* handle ciphertext stealing */
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skcipher_request_set_crypt(&subreq, src, dst,
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req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
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req->iv);
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err = skcipher_walk_virt(&walk, &subreq, false);
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if (err)
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return err;
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kernel_fpu_begin();
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aesni_cts_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
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walk.nbytes, walk.iv);
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kernel_fpu_end();
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return skcipher_walk_done(&walk, 0);
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}
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static int cts_cbc_decrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct crypto_aes_ctx *ctx = aes_ctx(crypto_skcipher_ctx(tfm));
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int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
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struct scatterlist *src = req->src, *dst = req->dst;
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struct scatterlist sg_src[2], sg_dst[2];
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struct skcipher_request subreq;
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struct skcipher_walk walk;
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int err;
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skcipher_request_set_tfm(&subreq, tfm);
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skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
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NULL, NULL);
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if (req->cryptlen <= AES_BLOCK_SIZE) {
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if (req->cryptlen < AES_BLOCK_SIZE)
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return -EINVAL;
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cbc_blocks = 1;
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}
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if (cbc_blocks > 0) {
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skcipher_request_set_crypt(&subreq, req->src, req->dst,
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cbc_blocks * AES_BLOCK_SIZE,
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req->iv);
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err = cbc_decrypt(&subreq);
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if (err)
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return err;
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if (req->cryptlen == AES_BLOCK_SIZE)
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return 0;
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dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
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if (req->dst != req->src)
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dst = scatterwalk_ffwd(sg_dst, req->dst,
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subreq.cryptlen);
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}
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/* handle ciphertext stealing */
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skcipher_request_set_crypt(&subreq, src, dst,
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req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
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req->iv);
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err = skcipher_walk_virt(&walk, &subreq, false);
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if (err)
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return err;
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kernel_fpu_begin();
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aesni_cts_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
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walk.nbytes, walk.iv);
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kernel_fpu_end();
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return skcipher_walk_done(&walk, 0);
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}
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#ifdef CONFIG_X86_64
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static void ctr_crypt_final(struct crypto_aes_ctx *ctx,
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struct skcipher_walk *walk)
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@ -928,6 +1044,23 @@ static struct skcipher_alg aesni_skciphers[] = {
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.setkey = aesni_skcipher_setkey,
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.encrypt = cbc_encrypt,
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.decrypt = cbc_decrypt,
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}, {
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.base = {
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.cra_name = "__cts(cbc(aes))",
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.cra_driver_name = "__cts-cbc-aes-aesni",
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.cra_priority = 400,
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.cra_flags = CRYPTO_ALG_INTERNAL,
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.cra_blocksize = AES_BLOCK_SIZE,
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.cra_ctxsize = CRYPTO_AES_CTX_SIZE,
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.cra_module = THIS_MODULE,
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},
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.min_keysize = AES_MIN_KEY_SIZE,
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.max_keysize = AES_MAX_KEY_SIZE,
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.ivsize = AES_BLOCK_SIZE,
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.walksize = 2 * AES_BLOCK_SIZE,
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.setkey = aesni_skcipher_setkey,
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.encrypt = cts_cbc_encrypt,
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.decrypt = cts_cbc_decrypt,
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#ifdef CONFIG_X86_64
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}, {
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.base = {
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