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![Eric Biggers](/assets/img/avatar_default.png)
The flag CRYPTO_ALG_ASYNC is "inherited" in the sense that when a template is instantiated, the template will have CRYPTO_ALG_ASYNC set if any of the algorithms it uses has CRYPTO_ALG_ASYNC set. We'd like to add a second flag (CRYPTO_ALG_ALLOCATES_MEMORY) that gets "inherited" in the same way. This is difficult because the handling of CRYPTO_ALG_ASYNC is hardcoded everywhere. Address this by: - Add CRYPTO_ALG_INHERITED_FLAGS, which contains the set of flags that have these inheritance semantics. - Add crypto_algt_inherited_mask(), for use by template ->create() methods. It returns any of these flags that the user asked to be unset and thus must be passed in the 'mask' to crypto_grab_*(). - Also modify crypto_check_attr_type() to handle computing the 'mask' so that most templates can just use this. - Make crypto_grab_*() propagate these flags to the template instance being created so that templates don't have to do this themselves. Make crypto/simd.c propagate these flags too, since it "wraps" another algorithm, similar to a template. Based on a patch by Mikulas Patocka <mpatocka@redhat.com> (https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
259 lines
6.4 KiB
C
259 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Cryptographic API.
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*
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* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* The HMAC implementation is derived from USAGI.
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* Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
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*/
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#include <crypto/hmac.h>
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#include <crypto/internal/hash.h>
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#include <crypto/scatterwalk.h>
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#include <linux/err.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/scatterlist.h>
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#include <linux/string.h>
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struct hmac_ctx {
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struct crypto_shash *hash;
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};
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static inline void *align_ptr(void *p, unsigned int align)
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{
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return (void *)ALIGN((unsigned long)p, align);
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}
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static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
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{
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return align_ptr(crypto_shash_ctx_aligned(tfm) +
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crypto_shash_statesize(tfm) * 2,
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crypto_tfm_ctx_alignment());
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}
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static int hmac_setkey(struct crypto_shash *parent,
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const u8 *inkey, unsigned int keylen)
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{
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int bs = crypto_shash_blocksize(parent);
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int ds = crypto_shash_digestsize(parent);
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int ss = crypto_shash_statesize(parent);
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char *ipad = crypto_shash_ctx_aligned(parent);
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char *opad = ipad + ss;
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struct hmac_ctx *ctx = align_ptr(opad + ss,
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crypto_tfm_ctx_alignment());
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struct crypto_shash *hash = ctx->hash;
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SHASH_DESC_ON_STACK(shash, hash);
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unsigned int i;
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shash->tfm = hash;
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if (keylen > bs) {
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int err;
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err = crypto_shash_digest(shash, inkey, keylen, ipad);
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if (err)
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return err;
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keylen = ds;
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} else
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memcpy(ipad, inkey, keylen);
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memset(ipad + keylen, 0, bs - keylen);
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memcpy(opad, ipad, bs);
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for (i = 0; i < bs; i++) {
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ipad[i] ^= HMAC_IPAD_VALUE;
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opad[i] ^= HMAC_OPAD_VALUE;
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}
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return crypto_shash_init(shash) ?:
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crypto_shash_update(shash, ipad, bs) ?:
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crypto_shash_export(shash, ipad) ?:
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crypto_shash_init(shash) ?:
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crypto_shash_update(shash, opad, bs) ?:
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crypto_shash_export(shash, opad);
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}
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static int hmac_export(struct shash_desc *pdesc, void *out)
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{
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struct shash_desc *desc = shash_desc_ctx(pdesc);
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return crypto_shash_export(desc, out);
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}
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static int hmac_import(struct shash_desc *pdesc, const void *in)
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{
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struct shash_desc *desc = shash_desc_ctx(pdesc);
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struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
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desc->tfm = ctx->hash;
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return crypto_shash_import(desc, in);
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}
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static int hmac_init(struct shash_desc *pdesc)
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{
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return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
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}
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static int hmac_update(struct shash_desc *pdesc,
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const u8 *data, unsigned int nbytes)
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{
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struct shash_desc *desc = shash_desc_ctx(pdesc);
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return crypto_shash_update(desc, data, nbytes);
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}
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static int hmac_final(struct shash_desc *pdesc, u8 *out)
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{
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struct crypto_shash *parent = pdesc->tfm;
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int ds = crypto_shash_digestsize(parent);
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int ss = crypto_shash_statesize(parent);
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char *opad = crypto_shash_ctx_aligned(parent) + ss;
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struct shash_desc *desc = shash_desc_ctx(pdesc);
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return crypto_shash_final(desc, out) ?:
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crypto_shash_import(desc, opad) ?:
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crypto_shash_finup(desc, out, ds, out);
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}
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static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
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unsigned int nbytes, u8 *out)
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{
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struct crypto_shash *parent = pdesc->tfm;
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int ds = crypto_shash_digestsize(parent);
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int ss = crypto_shash_statesize(parent);
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char *opad = crypto_shash_ctx_aligned(parent) + ss;
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struct shash_desc *desc = shash_desc_ctx(pdesc);
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return crypto_shash_finup(desc, data, nbytes, out) ?:
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crypto_shash_import(desc, opad) ?:
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crypto_shash_finup(desc, out, ds, out);
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}
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static int hmac_init_tfm(struct crypto_shash *parent)
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{
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struct crypto_shash *hash;
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struct shash_instance *inst = shash_alg_instance(parent);
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struct crypto_shash_spawn *spawn = shash_instance_ctx(inst);
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struct hmac_ctx *ctx = hmac_ctx(parent);
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hash = crypto_spawn_shash(spawn);
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if (IS_ERR(hash))
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return PTR_ERR(hash);
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parent->descsize = sizeof(struct shash_desc) +
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crypto_shash_descsize(hash);
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ctx->hash = hash;
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return 0;
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}
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static void hmac_exit_tfm(struct crypto_shash *parent)
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{
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struct hmac_ctx *ctx = hmac_ctx(parent);
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crypto_free_shash(ctx->hash);
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}
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static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct shash_instance *inst;
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struct crypto_shash_spawn *spawn;
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struct crypto_alg *alg;
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struct shash_alg *salg;
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u32 mask;
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int err;
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int ds;
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int ss;
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
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if (err)
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return err;
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inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
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if (!inst)
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return -ENOMEM;
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spawn = shash_instance_ctx(inst);
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err = crypto_grab_shash(spawn, shash_crypto_instance(inst),
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crypto_attr_alg_name(tb[1]), 0, mask);
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if (err)
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goto err_free_inst;
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salg = crypto_spawn_shash_alg(spawn);
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alg = &salg->base;
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/* The underlying hash algorithm must not require a key */
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err = -EINVAL;
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if (crypto_shash_alg_needs_key(salg))
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goto err_free_inst;
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ds = salg->digestsize;
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ss = salg->statesize;
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if (ds > alg->cra_blocksize ||
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ss < alg->cra_blocksize)
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goto err_free_inst;
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err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
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if (err)
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goto err_free_inst;
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inst->alg.base.cra_priority = alg->cra_priority;
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inst->alg.base.cra_blocksize = alg->cra_blocksize;
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inst->alg.base.cra_alignmask = alg->cra_alignmask;
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ss = ALIGN(ss, alg->cra_alignmask + 1);
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inst->alg.digestsize = ds;
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inst->alg.statesize = ss;
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inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
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ALIGN(ss * 2, crypto_tfm_ctx_alignment());
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inst->alg.init = hmac_init;
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inst->alg.update = hmac_update;
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inst->alg.final = hmac_final;
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inst->alg.finup = hmac_finup;
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inst->alg.export = hmac_export;
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inst->alg.import = hmac_import;
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inst->alg.setkey = hmac_setkey;
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inst->alg.init_tfm = hmac_init_tfm;
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inst->alg.exit_tfm = hmac_exit_tfm;
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inst->free = shash_free_singlespawn_instance;
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err = shash_register_instance(tmpl, inst);
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if (err) {
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err_free_inst:
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shash_free_singlespawn_instance(inst);
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}
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return err;
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}
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static struct crypto_template hmac_tmpl = {
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.name = "hmac",
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.create = hmac_create,
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.module = THIS_MODULE,
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};
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static int __init hmac_module_init(void)
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{
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return crypto_register_template(&hmac_tmpl);
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}
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static void __exit hmac_module_exit(void)
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{
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crypto_unregister_template(&hmac_tmpl);
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}
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subsys_initcall(hmac_module_init);
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module_exit(hmac_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("HMAC hash algorithm");
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MODULE_ALIAS_CRYPTO("hmac");
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