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![Eric Biggers](/assets/img/avatar_default.png)
We need to consistently enforce that keyed hashes cannot be used without setting the key. To do this we need a reliable way to determine whether a given hash algorithm is keyed or not. AF_ALG currently does this by checking for the presence of a ->setkey() method. However, this is actually slightly broken because the CRC-32 algorithms implement ->setkey() but can also be used without a key. (The CRC-32 "key" is not actually a cryptographic key but rather represents the initial state. If not overridden, then a default initial state is used.) Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which indicates that the algorithm has a ->setkey() method, but it is not required to be called. Then set it on all the CRC-32 algorithms. The same also applies to the Adler-32 implementation in Lustre. Also, the cryptd and mcryptd templates have to pass through the flag from their underlying algorithm. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
250 lines
5.6 KiB
C
250 lines
5.6 KiB
C
/*
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* Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions
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*
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* Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/cpufeature.h>
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#include <linux/crc32.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <crypto/internal/hash.h>
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#include <asm/hwcap.h>
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#include <asm/neon.h>
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#include <asm/simd.h>
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#include <asm/unaligned.h>
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#define PMULL_MIN_LEN 64L /* minimum size of buffer
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* for crc32_pmull_le_16 */
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#define SCALE_F 16L /* size of NEON register */
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asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc);
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asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len);
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asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc);
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asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len);
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static u32 (*fallback_crc32)(u32 init_crc, const u8 buf[], u32 len);
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static u32 (*fallback_crc32c)(u32 init_crc, const u8 buf[], u32 len);
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static int crc32_cra_init(struct crypto_tfm *tfm)
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{
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u32 *key = crypto_tfm_ctx(tfm);
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*key = 0;
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return 0;
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}
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static int crc32c_cra_init(struct crypto_tfm *tfm)
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{
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u32 *key = crypto_tfm_ctx(tfm);
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*key = ~0;
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return 0;
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}
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static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
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unsigned int keylen)
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{
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u32 *mctx = crypto_shash_ctx(hash);
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if (keylen != sizeof(u32)) {
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crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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*mctx = le32_to_cpup((__le32 *)key);
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return 0;
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}
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static int crc32_init(struct shash_desc *desc)
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{
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u32 *mctx = crypto_shash_ctx(desc->tfm);
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u32 *crc = shash_desc_ctx(desc);
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*crc = *mctx;
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return 0;
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}
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static int crc32_update(struct shash_desc *desc, const u8 *data,
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unsigned int length)
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{
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u32 *crc = shash_desc_ctx(desc);
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*crc = crc32_armv8_le(*crc, data, length);
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return 0;
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}
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static int crc32c_update(struct shash_desc *desc, const u8 *data,
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unsigned int length)
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{
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u32 *crc = shash_desc_ctx(desc);
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*crc = crc32c_armv8_le(*crc, data, length);
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return 0;
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}
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static int crc32_final(struct shash_desc *desc, u8 *out)
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{
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u32 *crc = shash_desc_ctx(desc);
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put_unaligned_le32(*crc, out);
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return 0;
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}
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static int crc32c_final(struct shash_desc *desc, u8 *out)
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{
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u32 *crc = shash_desc_ctx(desc);
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put_unaligned_le32(~*crc, out);
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return 0;
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}
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static int crc32_pmull_update(struct shash_desc *desc, const u8 *data,
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unsigned int length)
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{
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u32 *crc = shash_desc_ctx(desc);
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unsigned int l;
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if (may_use_simd()) {
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if ((u32)data % SCALE_F) {
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l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F));
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*crc = fallback_crc32(*crc, data, l);
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data += l;
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length -= l;
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}
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if (length >= PMULL_MIN_LEN) {
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l = round_down(length, SCALE_F);
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kernel_neon_begin();
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*crc = crc32_pmull_le(data, l, *crc);
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kernel_neon_end();
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data += l;
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length -= l;
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}
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}
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if (length > 0)
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*crc = fallback_crc32(*crc, data, length);
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return 0;
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}
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static int crc32c_pmull_update(struct shash_desc *desc, const u8 *data,
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unsigned int length)
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{
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u32 *crc = shash_desc_ctx(desc);
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unsigned int l;
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if (may_use_simd()) {
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if ((u32)data % SCALE_F) {
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l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F));
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*crc = fallback_crc32c(*crc, data, l);
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data += l;
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length -= l;
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}
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if (length >= PMULL_MIN_LEN) {
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l = round_down(length, SCALE_F);
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kernel_neon_begin();
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*crc = crc32c_pmull_le(data, l, *crc);
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kernel_neon_end();
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data += l;
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length -= l;
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}
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}
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if (length > 0)
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*crc = fallback_crc32c(*crc, data, length);
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return 0;
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}
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static struct shash_alg crc32_pmull_algs[] = { {
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.setkey = crc32_setkey,
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.init = crc32_init,
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.update = crc32_update,
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.final = crc32_final,
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.descsize = sizeof(u32),
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.digestsize = sizeof(u32),
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.base.cra_ctxsize = sizeof(u32),
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.base.cra_init = crc32_cra_init,
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.base.cra_name = "crc32",
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.base.cra_driver_name = "crc32-arm-ce",
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.base.cra_priority = 200,
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.base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
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.base.cra_blocksize = 1,
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.base.cra_module = THIS_MODULE,
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}, {
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.setkey = crc32_setkey,
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.init = crc32_init,
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.update = crc32c_update,
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.final = crc32c_final,
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.descsize = sizeof(u32),
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.digestsize = sizeof(u32),
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.base.cra_ctxsize = sizeof(u32),
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.base.cra_init = crc32c_cra_init,
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.base.cra_name = "crc32c",
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.base.cra_driver_name = "crc32c-arm-ce",
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.base.cra_priority = 200,
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.base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
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.base.cra_blocksize = 1,
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.base.cra_module = THIS_MODULE,
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} };
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static int __init crc32_pmull_mod_init(void)
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{
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if (elf_hwcap2 & HWCAP2_PMULL) {
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crc32_pmull_algs[0].update = crc32_pmull_update;
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crc32_pmull_algs[1].update = crc32c_pmull_update;
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if (elf_hwcap2 & HWCAP2_CRC32) {
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fallback_crc32 = crc32_armv8_le;
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fallback_crc32c = crc32c_armv8_le;
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} else {
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fallback_crc32 = crc32_le;
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fallback_crc32c = __crc32c_le;
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}
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} else if (!(elf_hwcap2 & HWCAP2_CRC32)) {
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return -ENODEV;
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}
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return crypto_register_shashes(crc32_pmull_algs,
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ARRAY_SIZE(crc32_pmull_algs));
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}
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static void __exit crc32_pmull_mod_exit(void)
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{
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crypto_unregister_shashes(crc32_pmull_algs,
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ARRAY_SIZE(crc32_pmull_algs));
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}
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static const struct cpu_feature crc32_cpu_feature[] = {
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{ cpu_feature(CRC32) }, { cpu_feature(PMULL) }, { }
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};
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MODULE_DEVICE_TABLE(cpu, crc32_cpu_feature);
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module_init(crc32_pmull_mod_init);
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module_exit(crc32_pmull_mod_exit);
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("crc32");
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MODULE_ALIAS_CRYPTO("crc32c");
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