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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-08-29 21:23:29 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-08-29 21:23:29 +0300 |
commit | 68cf01760bc0891074e813b9bb06d2696cac1c01 (patch) | |
tree | 0bfbd6a995c19df689476782450a7df8bd51b213 /lib/crypto/mpi/mpi-mod.c | |
parent | f97e18a3f2fb78a4ed0d25e427535d9f853b9e9e (diff) | |
parent | 85b9bf9a514d991fcecb118d0a8a35e754ff9265 (diff) | |
download | linux-68cf01760bc0891074e813b9bb06d2696cac1c01.tar.xz |
Merge tag 'v6.6-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"API:
- Move crypto engine callback from tfm ctx into algorithm object
- Fix atomic sleep bug in crypto_destroy_instance
- Move lib/mpi into lib/crypto
Algorithms:
- Add chacha20 and poly1305 implementation for powerpc p10
Drivers:
- Add AES skcipher and aead support to starfive
- Add Dynamic Boost Control support to ccp
- Add support for STM32P13 platform to stm32"
* tag 'v6.6-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (149 commits)
Revert "dt-bindings: crypto: qcom,prng: Add SM8450"
crypto: chelsio - Remove unused declarations
X.509: if signature is unsupported skip validation
crypto: qat - fix crypto capability detection for 4xxx
crypto: drivers - Explicitly include correct DT includes
crypto: engine - Remove crypto_engine_ctx
crypto: zynqmp - Use new crypto_engine_op interface
crypto: virtio - Use new crypto_engine_op interface
crypto: stm32 - Use new crypto_engine_op interface
crypto: jh7110 - Use new crypto_engine_op interface
crypto: rk3288 - Use new crypto_engine_op interface
crypto: omap - Use new crypto_engine_op interface
crypto: keembay - Use new crypto_engine_op interface
crypto: sl3516 - Use new crypto_engine_op interface
crypto: caam - Use new crypto_engine_op interface
crypto: aspeed - Remove non-standard sha512 algorithms
crypto: aspeed - Use new crypto_engine_op interface
crypto: amlogic - Use new crypto_engine_op interface
crypto: sun8i-ss - Use new crypto_engine_op interface
crypto: sun8i-ce - Use new crypto_engine_op interface
...
Diffstat (limited to 'lib/crypto/mpi/mpi-mod.c')
-rw-r--r-- | lib/crypto/mpi/mpi-mod.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/lib/crypto/mpi/mpi-mod.c b/lib/crypto/mpi/mpi-mod.c new file mode 100644 index 000000000000..54fcc01564d9 --- /dev/null +++ b/lib/crypto/mpi/mpi-mod.c @@ -0,0 +1,157 @@ +/* mpi-mod.c - Modular reduction + * Copyright (C) 1998, 1999, 2001, 2002, 2003, + * 2007 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + */ + + +#include "mpi-internal.h" +#include "longlong.h" + +/* Context used with Barrett reduction. */ +struct barrett_ctx_s { + MPI m; /* The modulus - may not be modified. */ + int m_copied; /* If true, M needs to be released. */ + int k; + MPI y; + MPI r1; /* Helper MPI. */ + MPI r2; /* Helper MPI. */ + MPI r3; /* Helper MPI allocated on demand. */ +}; + + + +void mpi_mod(MPI rem, MPI dividend, MPI divisor) +{ + mpi_fdiv_r(rem, dividend, divisor); +} + +/* This function returns a new context for Barrett based operations on + * the modulus M. This context needs to be released using + * _gcry_mpi_barrett_free. If COPY is true M will be transferred to + * the context and the user may change M. If COPY is false, M may not + * be changed until gcry_mpi_barrett_free has been called. + */ +mpi_barrett_t mpi_barrett_init(MPI m, int copy) +{ + mpi_barrett_t ctx; + MPI tmp; + + mpi_normalize(m); + ctx = kcalloc(1, sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return NULL; + + if (copy) { + ctx->m = mpi_copy(m); + ctx->m_copied = 1; + } else + ctx->m = m; + + ctx->k = mpi_get_nlimbs(m); + tmp = mpi_alloc(ctx->k + 1); + + /* Barrett precalculation: y = floor(b^(2k) / m). */ + mpi_set_ui(tmp, 1); + mpi_lshift_limbs(tmp, 2 * ctx->k); + mpi_fdiv_q(tmp, tmp, m); + + ctx->y = tmp; + ctx->r1 = mpi_alloc(2 * ctx->k + 1); + ctx->r2 = mpi_alloc(2 * ctx->k + 1); + + return ctx; +} + +void mpi_barrett_free(mpi_barrett_t ctx) +{ + if (ctx) { + mpi_free(ctx->y); + mpi_free(ctx->r1); + mpi_free(ctx->r2); + if (ctx->r3) + mpi_free(ctx->r3); + if (ctx->m_copied) + mpi_free(ctx->m); + kfree(ctx); + } +} + + +/* R = X mod M + * + * Using Barrett reduction. Before using this function + * _gcry_mpi_barrett_init must have been called to do the + * precalculations. CTX is the context created by this precalculation + * and also conveys M. If the Barret reduction could no be done a + * straightforward reduction method is used. + * + * We assume that these conditions are met: + * Input: x =(x_2k-1 ...x_0)_b + * m =(m_k-1 ....m_0)_b with m_k-1 != 0 + * Output: r = x mod m + */ +void mpi_mod_barrett(MPI r, MPI x, mpi_barrett_t ctx) +{ + MPI m = ctx->m; + int k = ctx->k; + MPI y = ctx->y; + MPI r1 = ctx->r1; + MPI r2 = ctx->r2; + int sign; + + mpi_normalize(x); + if (mpi_get_nlimbs(x) > 2*k) { + mpi_mod(r, x, m); + return; + } + + sign = x->sign; + x->sign = 0; + + /* 1. q1 = floor( x / b^k-1) + * q2 = q1 * y + * q3 = floor( q2 / b^k+1 ) + * Actually, we don't need qx, we can work direct on r2 + */ + mpi_set(r2, x); + mpi_rshift_limbs(r2, k-1); + mpi_mul(r2, r2, y); + mpi_rshift_limbs(r2, k+1); + + /* 2. r1 = x mod b^k+1 + * r2 = q3 * m mod b^k+1 + * r = r1 - r2 + * 3. if r < 0 then r = r + b^k+1 + */ + mpi_set(r1, x); + if (r1->nlimbs > k+1) /* Quick modulo operation. */ + r1->nlimbs = k+1; + mpi_mul(r2, r2, m); + if (r2->nlimbs > k+1) /* Quick modulo operation. */ + r2->nlimbs = k+1; + mpi_sub(r, r1, r2); + + if (mpi_has_sign(r)) { + if (!ctx->r3) { + ctx->r3 = mpi_alloc(k + 2); + mpi_set_ui(ctx->r3, 1); + mpi_lshift_limbs(ctx->r3, k + 1); + } + mpi_add(r, r, ctx->r3); + } + + /* 4. while r >= m do r = r - m */ + while (mpi_cmp(r, m) >= 0) + mpi_sub(r, r, m); + + x->sign = sign; +} + + +void mpi_mul_barrett(MPI w, MPI u, MPI v, mpi_barrett_t ctx) +{ + mpi_mul(w, u, v); + mpi_mod_barrett(w, w, ctx); +} |