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    Subject[PATCH RFC v1 3/3] crypto: sha1_generic - import lib/sha1.c locally
    Date
    With no non-crypto API users of this function, we can move it into the
    generic crypto/ code where it belongs.

    Cc: Geert Uytterhoeven <geert@linux-m68k.org>
    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: Ard Biesheuvel <ardb@kernel.org>
    Cc: linux-crypto@vger.kernel.org
    Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
    ---
    crypto/sha1_generic.c | 114 +++++++++++++++++++++++++++++++++++
    include/crypto/sha1.h | 10 ---
    lib/Makefile | 2 +-
    lib/sha1.c | 137 ------------------------------------------
    4 files changed, 115 insertions(+), 148 deletions(-)
    delete mode 100644 lib/sha1.c

    diff --git a/crypto/sha1_generic.c b/crypto/sha1_generic.c
    index 325b57fe28dc..a2b019803561 100644
    --- a/crypto/sha1_generic.c
    +++ b/crypto/sha1_generic.c
    @@ -16,9 +16,123 @@
    #include <linux/module.h>
    #include <linux/mm.h>
    #include <linux/types.h>
    +#include <linux/bitops.h>
    +#include <linux/string.h>
    #include <crypto/sha1.h>
    #include <crypto/sha1_base.h>
    #include <asm/byteorder.h>
    +#include <asm/unaligned.h>
    +
    +#define SHA1_DIGEST_WORDS (SHA1_DIGEST_SIZE / 4)
    +#define SHA1_WORKSPACE_WORDS 16
    +
    +/*
    + * If you have 32 registers or more, the compiler can (and should)
    + * try to change the array[] accesses into registers. However, on
    + * machines with less than ~25 registers, that won't really work,
    + * and at least gcc will make an unholy mess of it.
    + *
    + * So to avoid that mess which just slows things down, we force
    + * the stores to memory to actually happen (we might be better off
    + * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
    + * suggested by Artur Skawina - that will also make gcc unable to
    + * try to do the silly "optimize away loads" part because it won't
    + * see what the value will be).
    + *
    + * Ben Herrenschmidt reports that on PPC, the C version comes close
    + * to the optimized asm with this (ie on PPC you don't want that
    + * 'volatile', since there are lots of registers).
    + *
    + * On ARM we get the best code generation by forcing a full memory barrier
    + * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
    + * the stack frame size simply explode and performance goes down the drain.
    + */
    +
    +#ifdef CONFIG_X86
    + #define setW(x, val) (*(volatile __u32 *)&W(x) = (val))
    +#elif defined(CONFIG_ARM)
    + #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
    +#else
    + #define setW(x, val) (W(x) = (val))
    +#endif
    +
    +/* This "rolls" over the 512-bit array */
    +#define W(x) (array[(x)&15])
    +
    +/*
    + * Where do we get the source from? The first 16 iterations get it from
    + * the input data, the next mix it from the 512-bit array.
    + */
    +#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t)
    +#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
    +
    +#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
    + __u32 TEMP = input(t); setW(t, TEMP); \
    + E += TEMP + rol32(A,5) + (fn) + (constant); \
    + B = ror32(B, 2); \
    + TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0)
    +
    +#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
    +#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
    +#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
    +#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
    +#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E )
    +
    +/**
    + * sha1_transform - single block SHA1 transform (deprecated)
    + *
    + * @digest: 160 bit digest to update
    + * @data: 512 bits of data to hash
    + * @array: 16 words of workspace (see note)
    + *
    + * This function executes SHA-1's internal compression function. It updates the
    + * 160-bit internal state (@digest) with a single 512-bit data block (@data).
    + *
    + * Don't use this function. SHA-1 is no longer considered secure. And even if
    + * you do have to use SHA-1, this isn't the correct way to hash something with
    + * SHA-1 as this doesn't handle padding and finalization.
    + *
    + * Note: If the hash is security sensitive, the caller should be sure
    + * to clear the workspace. This is left to the caller to avoid
    + * unnecessary clears between chained hashing operations.
    + */
    +static void sha1_transform(__u32 *digest, const char *data, __u32 *array)
    +{
    + __u32 A, B, C, D, E;
    + unsigned int i = 0;
    +
    + A = digest[0];
    + B = digest[1];
    + C = digest[2];
    + D = digest[3];
    + E = digest[4];
    +
    + /* Round 1 - iterations 0-16 take their input from 'data' */
    + for (; i < 16; ++i)
    + T_0_15(i, A, B, C, D, E);
    +
    + /* Round 1 - tail. Input from 512-bit mixing array */
    + for (; i < 20; ++i)
    + T_16_19(i, A, B, C, D, E);
    +
    + /* Round 2 */
    + for (; i < 40; ++i)
    + T_20_39(i, A, B, C, D, E);
    +
    + /* Round 3 */
    + for (; i < 60; ++i)
    + T_40_59(i, A, B, C, D, E);
    +
    + /* Round 4 */
    + for (; i < 80; ++i)
    + T_60_79(i, A, B, C, D, E);
    +
    + digest[0] += A;
    + digest[1] += B;
    + digest[2] += C;
    + digest[3] += D;
    + digest[4] += E;
    +}

    const u8 sha1_zero_message_hash[SHA1_DIGEST_SIZE] = {
    0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d,
    diff --git a/include/crypto/sha1.h b/include/crypto/sha1.h
    index 044ecea60ac8..118a3cad5eb3 100644
    --- a/include/crypto/sha1.h
    +++ b/include/crypto/sha1.h
    @@ -33,14 +33,4 @@ extern int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
    extern int crypto_sha1_finup(struct shash_desc *desc, const u8 *data,
    unsigned int len, u8 *hash);

    -/*
    - * An implementation of SHA-1's compression function. Don't use in new code!
    - * You shouldn't be using SHA-1, and even if you *have* to use SHA-1, this isn't
    - * the correct way to hash something with SHA-1 (use crypto_shash instead).
    - */
    -#define SHA1_DIGEST_WORDS (SHA1_DIGEST_SIZE / 4)
    -#define SHA1_WORKSPACE_WORDS 16
    -void sha1_init(__u32 *buf);
    -void sha1_transform(__u32 *digest, const char *data, __u32 *W);
    -
    #endif /* _CRYPTO_SHA1_H */
    diff --git a/lib/Makefile b/lib/Makefile
    index 364c23f15578..83ac3f0c1fbe 100644
    --- a/lib/Makefile
    +++ b/lib/Makefile
    @@ -29,7 +29,7 @@ endif

    lib-y := ctype.o string.o vsprintf.o cmdline.o \
    rbtree.o radix-tree.o timerqueue.o xarray.o \
    - idr.o extable.o sha1.o irq_regs.o argv_split.o \
    + idr.o extable.o irq_regs.o argv_split.o \
    flex_proportions.o ratelimit.o show_mem.o \
    is_single_threaded.o plist.o decompress.o kobject_uevent.o \
    earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
    diff --git a/lib/sha1.c b/lib/sha1.c
    deleted file mode 100644
    index 0494766fc574..000000000000
    --- a/lib/sha1.c
    +++ /dev/null
    @@ -1,137 +0,0 @@
    -// SPDX-License-Identifier: GPL-2.0
    -/*
    - * SHA1 routine optimized to do word accesses rather than byte accesses,
    - * and to avoid unnecessary copies into the context array.
    - *
    - * This was based on the git SHA1 implementation.
    - */
    -
    -#include <linux/kernel.h>
    -#include <linux/export.h>
    -#include <linux/bitops.h>
    -#include <linux/string.h>
    -#include <crypto/sha1.h>
    -#include <asm/unaligned.h>
    -
    -/*
    - * If you have 32 registers or more, the compiler can (and should)
    - * try to change the array[] accesses into registers. However, on
    - * machines with less than ~25 registers, that won't really work,
    - * and at least gcc will make an unholy mess of it.
    - *
    - * So to avoid that mess which just slows things down, we force
    - * the stores to memory to actually happen (we might be better off
    - * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
    - * suggested by Artur Skawina - that will also make gcc unable to
    - * try to do the silly "optimize away loads" part because it won't
    - * see what the value will be).
    - *
    - * Ben Herrenschmidt reports that on PPC, the C version comes close
    - * to the optimized asm with this (ie on PPC you don't want that
    - * 'volatile', since there are lots of registers).
    - *
    - * On ARM we get the best code generation by forcing a full memory barrier
    - * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
    - * the stack frame size simply explode and performance goes down the drain.
    - */
    -
    -#ifdef CONFIG_X86
    - #define setW(x, val) (*(volatile __u32 *)&W(x) = (val))
    -#elif defined(CONFIG_ARM)
    - #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
    -#else
    - #define setW(x, val) (W(x) = (val))
    -#endif
    -
    -/* This "rolls" over the 512-bit array */
    -#define W(x) (array[(x)&15])
    -
    -/*
    - * Where do we get the source from? The first 16 iterations get it from
    - * the input data, the next mix it from the 512-bit array.
    - */
    -#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t)
    -#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
    -
    -#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
    - __u32 TEMP = input(t); setW(t, TEMP); \
    - E += TEMP + rol32(A,5) + (fn) + (constant); \
    - B = ror32(B, 2); \
    - TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0)
    -
    -#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
    -#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
    -#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
    -#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
    -#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E )
    -
    -/**
    - * sha1_transform - single block SHA1 transform (deprecated)
    - *
    - * @digest: 160 bit digest to update
    - * @data: 512 bits of data to hash
    - * @array: 16 words of workspace (see note)
    - *
    - * This function executes SHA-1's internal compression function. It updates the
    - * 160-bit internal state (@digest) with a single 512-bit data block (@data).
    - *
    - * Don't use this function. SHA-1 is no longer considered secure. And even if
    - * you do have to use SHA-1, this isn't the correct way to hash something with
    - * SHA-1 as this doesn't handle padding and finalization.
    - *
    - * Note: If the hash is security sensitive, the caller should be sure
    - * to clear the workspace. This is left to the caller to avoid
    - * unnecessary clears between chained hashing operations.
    - */
    -void sha1_transform(__u32 *digest, const char *data, __u32 *array)
    -{
    - __u32 A, B, C, D, E;
    - unsigned int i = 0;
    -
    - A = digest[0];
    - B = digest[1];
    - C = digest[2];
    - D = digest[3];
    - E = digest[4];
    -
    - /* Round 1 - iterations 0-16 take their input from 'data' */
    - for (; i < 16; ++i)
    - T_0_15(i, A, B, C, D, E);
    -
    - /* Round 1 - tail. Input from 512-bit mixing array */
    - for (; i < 20; ++i)
    - T_16_19(i, A, B, C, D, E);
    -
    - /* Round 2 */
    - for (; i < 40; ++i)
    - T_20_39(i, A, B, C, D, E);
    -
    - /* Round 3 */
    - for (; i < 60; ++i)
    - T_40_59(i, A, B, C, D, E);
    -
    - /* Round 4 */
    - for (; i < 80; ++i)
    - T_60_79(i, A, B, C, D, E);
    -
    - digest[0] += A;
    - digest[1] += B;
    - digest[2] += C;
    - digest[3] += D;
    - digest[4] += E;
    -}
    -EXPORT_SYMBOL(sha1_transform);
    -
    -/**
    - * sha1_init - initialize the vectors for a SHA1 digest
    - * @buf: vector to initialize
    - */
    -void sha1_init(__u32 *buf)
    -{
    - buf[0] = 0x67452301;
    - buf[1] = 0xefcdab89;
    - buf[2] = 0x98badcfe;
    - buf[3] = 0x10325476;
    - buf[4] = 0xc3d2e1f0;
    -}
    -EXPORT_SYMBOL(sha1_init);
    --
    2.34.1
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