From fca5cb4dd2b4a9423cb6d112cc71c33899955a1f Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 10 Aug 2024 14:20:55 +0800 Subject: Revert "lib/mpi: Extend the MPI library" This partially reverts commit a8ea8bdd9df92a0e5db5b43900abb7a288b8a53e. Most of it is no longer needed since sm2 has been removed. However, the following functions have been kept as they have developed other uses: mpi_copy mpi_mod mpi_test_bit mpi_set_bit mpi_rshift mpi_add mpi_sub mpi_addm mpi_subm mpi_mul mpi_mulm mpi_tdiv_r mpi_fdiv_r Signed-off-by: Herbert Xu --- lib/crypto/mpi/mpi-mod.c | 144 ----------------------------------------------- 1 file changed, 144 deletions(-) (limited to 'lib/crypto/mpi/mpi-mod.c') diff --git a/lib/crypto/mpi/mpi-mod.c b/lib/crypto/mpi/mpi-mod.c index 54fcc01564d9..691bbdc52fc6 100644 --- a/lib/crypto/mpi/mpi-mod.c +++ b/lib/crypto/mpi/mpi-mod.c @@ -5,153 +5,9 @@ * 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); -} -- cgit From 8e3a67f2de87ee94ac11ea69beb4edc2993b17a0 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 10 Aug 2024 14:20:57 +0800 Subject: crypto: lib/mpi - Add error checks to extension The remaining functions added by commit a8ea8bdd9df92a0e5db5b43900abb7a288b8a53e did not check for memory allocation errors. Add the checks and change the API to allow errors to be returned. Fixes: a8ea8bdd9df9 ("lib/mpi: Extend the MPI library") Signed-off-by: Herbert Xu --- lib/crypto/mpi/mpi-mod.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib/crypto/mpi/mpi-mod.c') diff --git a/lib/crypto/mpi/mpi-mod.c b/lib/crypto/mpi/mpi-mod.c index 691bbdc52fc6..d5fdaec3d0b6 100644 --- a/lib/crypto/mpi/mpi-mod.c +++ b/lib/crypto/mpi/mpi-mod.c @@ -7,7 +7,7 @@ #include "mpi-internal.h" -void mpi_mod(MPI rem, MPI dividend, MPI divisor) +int mpi_mod(MPI rem, MPI dividend, MPI divisor) { - mpi_fdiv_r(rem, dividend, divisor); + return mpi_fdiv_r(rem, dividend, divisor); } -- cgit