// SPDX-License-Identifier: GPL-2.0-or-later/* * Symmetric key cipher operations. * * Generic encrypt/decrypt wrapper for ciphers, handles operations across * multiple page boundaries by using temporary blocks.  In user context, * the kernel is given a chance to schedule us once per page. * * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> */ #include <crypto/internal/aead.h>#include <crypto/internal/cipher.h>#include <crypto/internal/skcipher.h>#include <crypto/scatterwalk.h>#include <linux/bug.h>#include <linux/cryptouser.h>#include <linux/err.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/seq_file.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/string_choices.h>#include <net/netlink.h>#include "skcipher.h" #define CRYPTO_ALG_TYPE_SKCIPHER_MASK	0x0000000e enum {	SKCIPHER_WALK_SLOW = 1 << 0,	SKCIPHER_WALK_COPY = 1 << 1,	SKCIPHER_WALK_DIFF = 1 << 2,	SKCIPHER_WALK_SLEEP = 1 << 3,}; static const struct crypto_type crypto_skcipher_type; static int skcipher_walk_next(struct skcipher_walk *walk); static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk){	return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;} static inline struct skcipher_alg *__crypto_skcipher_alg(	struct crypto_alg *alg){	return container_of(alg, struct skcipher_alg, base);} /** * skcipher_walk_done() - finish one step of a skcipher_walk * @walk: the skcipher_walk * @res: number of bytes *not* processed (>= 0) from walk->nbytes, *	 or a -errno value to terminate the walk due to an error * * This function cleans up after one step of walking through the source and * destination scatterlists, and advances to the next step if applicable. * walk->nbytes is set to the number of bytes available in the next step, * walk->total is set to the new total number of bytes remaining, and * walk->{src,dst}.virt.addr is set to the next pair of data pointers.  If there * is no more data, or if an error occurred (i.e. -errno return), then * walk->nbytes and walk->total are set to 0 and all resources owned by the * skcipher_walk are freed. * * Return: 0 or a -errno value.  If @res was a -errno value then it will be *	   returned, but other errors may occur too. */int skcipher_walk_done(struct skcipher_walk *walk, int res){	unsigned int n = walk->nbytes; /* num bytes processed this step */	unsigned int total = 0; /* new total remaining */ 	if (!n)		goto finish; 	if (likely(res >= 0)) {		n -= res; /* subtract num bytes *not* processed */		total = walk->total - n;	} 	if (likely(!(walk->flags & (SKCIPHER_WALK_SLOW |				    SKCIPHER_WALK_COPY |				    SKCIPHER_WALK_DIFF)))) {		scatterwalk_advance(&walk->in, n);	} else if (walk->flags & SKCIPHER_WALK_DIFF) {		scatterwalk_done_src(&walk->in, n);	} else if (walk->flags & SKCIPHER_WALK_COPY) {		scatterwalk_advance(&walk->in, n);		scatterwalk_map(&walk->out);		memcpy(walk->out.addr, walk->page, n);	} else { /* SKCIPHER_WALK_SLOW */		if (res > 0) {			/*			 * Didn't process all bytes.  Either the algorithm is			 * broken, or this was the last step and it turned out			 * the message wasn't evenly divisible into blocks but			 * the algorithm requires it.			 */			res = -EINVAL;			total = 0;		} else			memcpy_to_scatterwalk(&walk->out, walk->out.addr, n);		goto dst_done;	} 	scatterwalk_done_dst(&walk->out, n);dst_done: 	if (res > 0)		res = 0; 	walk->total = total;	walk->nbytes = 0; 	if (total) {		if (walk->flags & SKCIPHER_WALK_SLEEP)			cond_resched();		walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |				 SKCIPHER_WALK_DIFF);		return skcipher_walk_next(walk);	} finish:	/* Short-circuit for the common/fast path. */	if (!((unsigned long)walk->buffer | (unsigned long)walk->page))		goto out; 	if (walk->iv != walk->oiv)		memcpy(walk->oiv, walk->iv, walk->ivsize);	if (walk->buffer != walk->page)		kfree(walk->buffer);	if (walk->page)		free_page((unsigned long)walk->page); out:	return res;}EXPORT_SYMBOL_GPL(skcipher_walk_done); static int skcipher_next_slow(struct skcipher_walk *walk, unsigned int bsize){	unsigned alignmask = walk->alignmask;	unsigned n;	void *buffer; 	if (!walk->buffer)		walk->buffer = walk->page;	buffer = walk->buffer;	if (!buffer) {		/* Min size for a buffer of bsize bytes aligned to alignmask */		n = bsize + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); 		buffer = kzalloc(n, skcipher_walk_gfp(walk));		if (!buffer)			return skcipher_walk_done(walk, -ENOMEM);		walk->buffer = buffer;	} 	buffer = PTR_ALIGN(buffer, alignmask + 1);	memcpy_from_scatterwalk(buffer, &walk->in, bsize);	walk->out.__addr = buffer;	walk->in.__addr = walk->out.addr; 	walk->nbytes = bsize;	walk->flags |= SKCIPHER_WALK_SLOW; 	return 0;} static int skcipher_next_copy(struct skcipher_walk *walk){	void *tmp = walk->page; 	scatterwalk_map(&walk->in);	memcpy(tmp, walk->in.addr, walk->nbytes);	scatterwalk_unmap(&walk->in);	/*	 * walk->in is advanced later when the number of bytes actually	 * processed (which might be less than walk->nbytes) is known.	 */ 	walk->in.__addr = tmp;	walk->out.__addr = tmp;	return 0;} static int skcipher_next_fast(struct skcipher_walk *walk){	unsigned long diff; 	diff = offset_in_page(walk->in.offset) -	       offset_in_page(walk->out.offset);	diff |= (u8 *)(sg_page(walk->in.sg) + (walk->in.offset >> PAGE_SHIFT)) -		(u8 *)(sg_page(walk->out.sg) + (walk->out.offset >> PAGE_SHIFT)); 	scatterwalk_map(&walk->out);	walk->in.__addr = walk->out.__addr; 	if (diff) {		walk->flags |= SKCIPHER_WALK_DIFF;		scatterwalk_map(&walk->in);	} 	return 0;} static int skcipher_walk_next(struct skcipher_walk *walk){	unsigned int bsize;	unsigned int n; 	n = walk->total;	bsize = min(walk->stride, max(n, walk->blocksize));	n = scatterwalk_clamp(&walk->in, n);	n = scatterwalk_clamp(&walk->out, n); 	if (unlikely(n < bsize)) {		if (unlikely(walk->total < walk->blocksize))			return skcipher_walk_done(walk, -EINVAL); slow_path:		return skcipher_next_slow(walk, bsize);	}	walk->nbytes = n; 	if (unlikely((walk->in.offset | walk->out.offset) & walk->alignmask)) {		if (!walk->page) {			gfp_t gfp = skcipher_walk_gfp(walk); 			walk->page = (void *)__get_free_page(gfp);			if (!walk->page)				goto slow_path;		}		walk->flags |= SKCIPHER_WALK_COPY;		return skcipher_next_copy(walk);	} 	return skcipher_next_fast(walk);} static int skcipher_copy_iv(struct skcipher_walk *walk){	unsigned alignmask = walk->alignmask;	unsigned ivsize = walk->ivsize;	unsigned aligned_stride = ALIGN(walk->stride, alignmask + 1);	unsigned size;	u8 *iv; 	/* Min size for a buffer of stride + ivsize, aligned to alignmask */	size = aligned_stride + ivsize +	       (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); 	walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));	if (!walk->buffer)		return -ENOMEM; 	iv = PTR_ALIGN(walk->buffer, alignmask + 1) + aligned_stride; 	walk->iv = memcpy(iv, walk->iv, walk->ivsize);	return 0;} static int skcipher_walk_first(struct skcipher_walk *walk){	if (WARN_ON_ONCE(in_hardirq()))		return -EDEADLK; 	walk->buffer = NULL;	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {		int err = skcipher_copy_iv(walk);		if (err)			return err;	} 	walk->page = NULL; 	return skcipher_walk_next(walk);} int skcipher_walk_virt(struct skcipher_walk *__restrict walk,		       struct skcipher_request *__restrict req, bool atomic){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct skcipher_alg *alg; 	might_sleep_if(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP); 	alg = crypto_skcipher_alg(tfm); 	walk->total = req->cryptlen;	walk->nbytes = 0;	walk->iv = req->iv;	walk->oiv = req->iv;	if ((req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) && !atomic)		walk->flags = SKCIPHER_WALK_SLEEP;	else		walk->flags = 0; 	if (unlikely(!walk->total))		return 0; 	scatterwalk_start(&walk->in, req->src);	scatterwalk_start(&walk->out, req->dst); 	walk->blocksize = crypto_skcipher_blocksize(tfm);	walk->ivsize = crypto_skcipher_ivsize(tfm);	walk->alignmask = crypto_skcipher_alignmask(tfm); 	if (alg->co.base.cra_type != &crypto_skcipher_type)		walk->stride = alg->co.chunksize;	else		walk->stride = alg->walksize; 	return skcipher_walk_first(walk);}EXPORT_SYMBOL_GPL(skcipher_walk_virt); static int skcipher_walk_aead_common(struct skcipher_walk *__restrict walk,				     struct aead_request *__restrict req,				     bool atomic){	struct crypto_aead *tfm = crypto_aead_reqtfm(req); 	walk->nbytes = 0;	walk->iv = req->iv;	walk->oiv = req->iv;	if ((req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) && !atomic)		walk->flags = SKCIPHER_WALK_SLEEP;	else		walk->flags = 0; 	if (unlikely(!walk->total))		return 0; 	scatterwalk_start_at_pos(&walk->in, req->src, req->assoclen);	scatterwalk_start_at_pos(&walk->out, req->dst, req->assoclen); 	walk->blocksize = crypto_aead_blocksize(tfm);	walk->stride = crypto_aead_chunksize(tfm);	walk->ivsize = crypto_aead_ivsize(tfm);	walk->alignmask = crypto_aead_alignmask(tfm); 	return skcipher_walk_first(walk);} int skcipher_walk_aead_encrypt(struct skcipher_walk *__restrict walk,			       struct aead_request *__restrict req,			       bool atomic){	walk->total = req->cryptlen; 	return skcipher_walk_aead_common(walk, req, atomic);}EXPORT_SYMBOL_GPL(skcipher_walk_aead_encrypt); int skcipher_walk_aead_decrypt(struct skcipher_walk *__restrict walk,			       struct aead_request *__restrict req,			       bool atomic){	struct crypto_aead *tfm = crypto_aead_reqtfm(req); 	walk->total = req->cryptlen - crypto_aead_authsize(tfm); 	return skcipher_walk_aead_common(walk, req, atomic);}EXPORT_SYMBOL_GPL(skcipher_walk_aead_decrypt); static void skcipher_set_needkey(struct crypto_skcipher *tfm){	if (crypto_skcipher_max_keysize(tfm) != 0)		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_NEED_KEY);} static int skcipher_setkey_unaligned(struct crypto_skcipher *tfm,				     const u8 *key, unsigned int keylen){	unsigned long alignmask = crypto_skcipher_alignmask(tfm);	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);	u8 *buffer, *alignbuffer;	unsigned long absize;	int ret; 	absize = keylen + alignmask;	buffer = kmalloc(absize, GFP_ATOMIC);	if (!buffer)		return -ENOMEM; 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);	memcpy(alignbuffer, key, keylen);	ret = cipher->setkey(tfm, alignbuffer, keylen);	kfree_sensitive(buffer);	return ret;} int crypto_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,			   unsigned int keylen){	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);	unsigned long alignmask = crypto_skcipher_alignmask(tfm);	int err; 	if (cipher->co.base.cra_type != &crypto_skcipher_type) {		struct crypto_lskcipher **ctx = crypto_skcipher_ctx(tfm); 		crypto_lskcipher_clear_flags(*ctx, CRYPTO_TFM_REQ_MASK);		crypto_lskcipher_set_flags(*ctx,					   crypto_skcipher_get_flags(tfm) &					   CRYPTO_TFM_REQ_MASK);		err = crypto_lskcipher_setkey(*ctx, key, keylen);		goto out;	} 	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize)		return -EINVAL; 	if ((unsigned long)key & alignmask)		err = skcipher_setkey_unaligned(tfm, key, keylen);	else		err = cipher->setkey(tfm, key, keylen); out:	if (unlikely(err)) {		skcipher_set_needkey(tfm);		return err;	} 	crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);	return 0;}EXPORT_SYMBOL_GPL(crypto_skcipher_setkey); int crypto_skcipher_encrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct skcipher_alg *alg = crypto_skcipher_alg(tfm); 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)		return -ENOKEY;	if (alg->co.base.cra_type != &crypto_skcipher_type)		return crypto_lskcipher_encrypt_sg(req);	return alg->encrypt(req);}EXPORT_SYMBOL_GPL(crypto_skcipher_encrypt); int crypto_skcipher_decrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct skcipher_alg *alg = crypto_skcipher_alg(tfm); 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)		return -ENOKEY;	if (alg->co.base.cra_type != &crypto_skcipher_type)		return crypto_lskcipher_decrypt_sg(req);	return alg->decrypt(req);}EXPORT_SYMBOL_GPL(crypto_skcipher_decrypt); static int crypto_lskcipher_export(struct skcipher_request *req, void *out){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	u8 *ivs = skcipher_request_ctx(req); 	ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1); 	memcpy(out, ivs + crypto_skcipher_ivsize(tfm),	       crypto_skcipher_statesize(tfm)); 	return 0;} static int crypto_lskcipher_import(struct skcipher_request *req, const void *in){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	u8 *ivs = skcipher_request_ctx(req); 	ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1); 	memcpy(ivs + crypto_skcipher_ivsize(tfm), in,	       crypto_skcipher_statesize(tfm)); 	return 0;} static int skcipher_noexport(struct skcipher_request *req, void *out){	return 0;} static int skcipher_noimport(struct skcipher_request *req, const void *in){	return 0;} int crypto_skcipher_export(struct skcipher_request *req, void *out){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);

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