From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- lib/crypto/md5.c | 302 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 302 insertions(+) create mode 100644 lib/crypto/md5.c (limited to 'lib/crypto/md5.c') diff --git a/lib/crypto/md5.c b/lib/crypto/md5.c new file mode 100644 index 000000000..3d2b017a0 --- /dev/null +++ b/lib/crypto/md5.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * MD5 and HMAC-MD5 library functions + * + * md5_block() is derived from cryptoapi implementation, originally based on the + * public domain implementation written by Colin Plumb in 1993. + * + * Copyright (c) Cryptoapi developers. + * Copyright (c) 2002 James Morris + * Copyright 2025 Google LLC + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static const struct md5_block_state md5_iv = { + .h = { MD5_H0, MD5_H1, MD5_H2, MD5_H3 }, +}; + +#define F1(x, y, z) (z ^ (x & (y ^ z))) +#define F2(x, y, z) F1(z, x, y) +#define F3(x, y, z) (x ^ y ^ z) +#define F4(x, y, z) (y ^ (x | ~z)) + +#define MD5STEP(f, w, x, y, z, in, s) \ + (w += f(x, y, z) + in, w = rol32(w, s) + x) + +static void md5_block(struct md5_block_state *state, + const u8 data[MD5_BLOCK_SIZE]) +{ + u32 in[MD5_BLOCK_WORDS]; + u32 a, b, c, d; + + memcpy(in, data, MD5_BLOCK_SIZE); + le32_to_cpu_array(in, ARRAY_SIZE(in)); + + a = state->h[0]; + b = state->h[1]; + c = state->h[2]; + d = state->h[3]; + + MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); + MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); + MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); + MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); + MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); + MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); + MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); + MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); + MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); + MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); + MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); + MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); + MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); + MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); + MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); + MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); + + MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); + MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); + MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); + MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); + MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); + MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); + MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); + MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); + MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); + MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); + MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); + MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); + MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); + MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); + MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); + MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); + + MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); + MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); + MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); + MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); + MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); + MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); + MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); + MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); + MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); + MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); + MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); + MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); + MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); + MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); + MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); + MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); + + MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); + MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); + MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); + MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); + MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); + MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); + MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); + MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); + MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); + MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); + MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); + MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); + MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); + MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); + MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); + MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); + + state->h[0] += a; + state->h[1] += b; + state->h[2] += c; + state->h[3] += d; +} + +static void md5_blocks(struct md5_block_state *state, + const u8 *data, size_t nblocks) +{ + do { + md5_block(state, data); + data += MD5_BLOCK_SIZE; + } while (--nblocks); +} + +void md5_init(struct md5_ctx *ctx) +{ + ctx->state = md5_iv; + ctx->bytecount = 0; +} +EXPORT_SYMBOL_GPL(md5_init); + +void md5_update(struct md5_ctx *ctx, const u8 *data, size_t len) +{ + size_t partial = ctx->bytecount % MD5_BLOCK_SIZE; + + ctx->bytecount += len; + + if (partial + len >= MD5_BLOCK_SIZE) { + size_t nblocks; + + if (partial) { + size_t l = MD5_BLOCK_SIZE - partial; + + memcpy(&ctx->buf[partial], data, l); + data += l; + len -= l; + + md5_blocks(&ctx->state, ctx->buf, 1); + } + + nblocks = len / MD5_BLOCK_SIZE; + len %= MD5_BLOCK_SIZE; + + if (nblocks) { + md5_blocks(&ctx->state, data, nblocks); + data += nblocks * MD5_BLOCK_SIZE; + } + partial = 0; + } + if (len) + memcpy(&ctx->buf[partial], data, len); +} +EXPORT_SYMBOL_GPL(md5_update); + +static void __md5_final(struct md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) +{ + u64 bitcount = ctx->bytecount << 3; + size_t partial = ctx->bytecount % MD5_BLOCK_SIZE; + + ctx->buf[partial++] = 0x80; + if (partial > MD5_BLOCK_SIZE - 8) { + memset(&ctx->buf[partial], 0, MD5_BLOCK_SIZE - partial); + md5_blocks(&ctx->state, ctx->buf, 1); + partial = 0; + } + memset(&ctx->buf[partial], 0, MD5_BLOCK_SIZE - 8 - partial); + *(__le64 *)&ctx->buf[MD5_BLOCK_SIZE - 8] = cpu_to_le64(bitcount); + md5_blocks(&ctx->state, ctx->buf, 1); + + cpu_to_le32_array(ctx->state.h, ARRAY_SIZE(ctx->state.h)); + memcpy(out, ctx->state.h, MD5_DIGEST_SIZE); +} + +void md5_final(struct md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) +{ + __md5_final(ctx, out); + memzero_explicit(ctx, sizeof(*ctx)); +} +EXPORT_SYMBOL_GPL(md5_final); + +void md5(const u8 *data, size_t len, u8 out[MD5_DIGEST_SIZE]) +{ + struct md5_ctx ctx; + + md5_init(&ctx); + md5_update(&ctx, data, len); + md5_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(md5); + +static void __hmac_md5_preparekey(struct md5_block_state *istate, + struct md5_block_state *ostate, + const u8 *raw_key, size_t raw_key_len) +{ + union { + u8 b[MD5_BLOCK_SIZE]; + unsigned long w[MD5_BLOCK_SIZE / sizeof(unsigned long)]; + } derived_key = { 0 }; + + if (unlikely(raw_key_len > MD5_BLOCK_SIZE)) + md5(raw_key, raw_key_len, derived_key.b); + else + memcpy(derived_key.b, raw_key, raw_key_len); + + for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) + derived_key.w[i] ^= REPEAT_BYTE(HMAC_IPAD_VALUE); + *istate = md5_iv; + md5_blocks(istate, derived_key.b, 1); + + for (size_t i = 0; i < ARRAY_SIZE(derived_key.w); i++) + derived_key.w[i] ^= REPEAT_BYTE(HMAC_OPAD_VALUE ^ + HMAC_IPAD_VALUE); + *ostate = md5_iv; + md5_blocks(ostate, derived_key.b, 1); + + memzero_explicit(&derived_key, sizeof(derived_key)); +} + +void hmac_md5_preparekey(struct hmac_md5_key *key, + const u8 *raw_key, size_t raw_key_len) +{ + __hmac_md5_preparekey(&key->istate, &key->ostate, raw_key, raw_key_len); +} +EXPORT_SYMBOL_GPL(hmac_md5_preparekey); + +void hmac_md5_init(struct hmac_md5_ctx *ctx, const struct hmac_md5_key *key) +{ + ctx->hash_ctx.state = key->istate; + ctx->hash_ctx.bytecount = MD5_BLOCK_SIZE; + ctx->ostate = key->ostate; +} +EXPORT_SYMBOL_GPL(hmac_md5_init); + +void hmac_md5_init_usingrawkey(struct hmac_md5_ctx *ctx, + const u8 *raw_key, size_t raw_key_len) +{ + __hmac_md5_preparekey(&ctx->hash_ctx.state, &ctx->ostate, + raw_key, raw_key_len); + ctx->hash_ctx.bytecount = MD5_BLOCK_SIZE; +} +EXPORT_SYMBOL_GPL(hmac_md5_init_usingrawkey); + +void hmac_md5_final(struct hmac_md5_ctx *ctx, u8 out[MD5_DIGEST_SIZE]) +{ + /* Generate the padded input for the outer hash in ctx->hash_ctx.buf. */ + __md5_final(&ctx->hash_ctx, ctx->hash_ctx.buf); + memset(&ctx->hash_ctx.buf[MD5_DIGEST_SIZE], 0, + MD5_BLOCK_SIZE - MD5_DIGEST_SIZE); + ctx->hash_ctx.buf[MD5_DIGEST_SIZE] = 0x80; + *(__le64 *)&ctx->hash_ctx.buf[MD5_BLOCK_SIZE - 8] = + cpu_to_le64(8 * (MD5_BLOCK_SIZE + MD5_DIGEST_SIZE)); + + /* Compute the outer hash, which gives the HMAC value. */ + md5_blocks(&ctx->ostate, ctx->hash_ctx.buf, 1); + cpu_to_le32_array(ctx->ostate.h, ARRAY_SIZE(ctx->ostate.h)); + memcpy(out, ctx->ostate.h, MD5_DIGEST_SIZE); + + memzero_explicit(ctx, sizeof(*ctx)); +} +EXPORT_SYMBOL_GPL(hmac_md5_final); + +void hmac_md5(const struct hmac_md5_key *key, + const u8 *data, size_t data_len, u8 out[MD5_DIGEST_SIZE]) +{ + struct hmac_md5_ctx ctx; + + hmac_md5_init(&ctx, key); + hmac_md5_update(&ctx, data, data_len); + hmac_md5_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(hmac_md5); + +void hmac_md5_usingrawkey(const u8 *raw_key, size_t raw_key_len, + const u8 *data, size_t data_len, + u8 out[MD5_DIGEST_SIZE]) +{ + struct hmac_md5_ctx ctx; + + hmac_md5_init_usingrawkey(&ctx, raw_key, raw_key_len); + hmac_md5_update(&ctx, data, data_len); + hmac_md5_final(&ctx, out); +} +EXPORT_SYMBOL_GPL(hmac_md5_usingrawkey); + +MODULE_DESCRIPTION("MD5 and HMAC-MD5 library functions"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1