/* * 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> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #include <crypto/internal/aead.h>#include <crypto/internal/skcipher.h>#include <crypto/scatterwalk.h>#include <linux/bug.h>#include <linux/cryptouser.h>#include <linux/compiler.h>#include <linux/list.h>#include <linux/module.h>#include <linux/rtnetlink.h>#include <linux/seq_file.h>#include <net/netlink.h> #include "internal.h" enum {	SKCIPHER_WALK_PHYS = 1 << 0,	SKCIPHER_WALK_SLOW = 1 << 1,	SKCIPHER_WALK_COPY = 1 << 2,	SKCIPHER_WALK_DIFF = 1 << 3,	SKCIPHER_WALK_SLEEP = 1 << 4,}; struct skcipher_walk_buffer {	struct list_head entry;	struct scatter_walk dst;	unsigned int len;	u8 *data;	u8 buffer[];}; static int skcipher_walk_next(struct skcipher_walk *walk); static inline void skcipher_unmap(struct scatter_walk *walk, void *vaddr){	if (PageHighMem(scatterwalk_page(walk)))		kunmap_atomic(vaddr);} static inline void *skcipher_map(struct scatter_walk *walk){	struct page *page = scatterwalk_page(walk); 	return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) +	       offset_in_page(walk->offset);} static inline void skcipher_map_src(struct skcipher_walk *walk){	walk->src.virt.addr = skcipher_map(&walk->in);} static inline void skcipher_map_dst(struct skcipher_walk *walk){	walk->dst.virt.addr = skcipher_map(&walk->out);} static inline void skcipher_unmap_src(struct skcipher_walk *walk){	skcipher_unmap(&walk->in, walk->src.virt.addr);} static inline void skcipher_unmap_dst(struct skcipher_walk *walk){	skcipher_unmap(&walk->out, walk->dst.virt.addr);} static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk){	return walk->flags & SKCIPHER_WALK_SLEEP ? GFP_KERNEL : GFP_ATOMIC;} /* Get a spot of the specified length that does not straddle a page. * The caller needs to ensure that there is enough space for this operation. */static inline u8 *skcipher_get_spot(u8 *start, unsigned int len){	u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK); 	return max(start, end_page);} static int skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize){	u8 *addr; 	addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);	addr = skcipher_get_spot(addr, bsize);	scatterwalk_copychunks(addr, &walk->out, bsize,			       (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1);	return 0;} int skcipher_walk_done(struct skcipher_walk *walk, int err){	unsigned int n = walk->nbytes - err;	unsigned int nbytes; 	nbytes = walk->total - n; 	if (unlikely(err < 0)) {		nbytes = 0;		n = 0;	} else if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS |					   SKCIPHER_WALK_SLOW |					   SKCIPHER_WALK_COPY |					   SKCIPHER_WALK_DIFF)))) {unmap_src:		skcipher_unmap_src(walk);	} else if (walk->flags & SKCIPHER_WALK_DIFF) {		skcipher_unmap_dst(walk);		goto unmap_src;	} else if (walk->flags & SKCIPHER_WALK_COPY) {		skcipher_map_dst(walk);		memcpy(walk->dst.virt.addr, walk->page, n);		skcipher_unmap_dst(walk);	} else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {		if (WARN_ON(err)) {			err = -EINVAL;			nbytes = 0;		} else			n = skcipher_done_slow(walk, n);	} 	if (err > 0)		err = 0; 	walk->total = nbytes;	walk->nbytes = nbytes; 	scatterwalk_advance(&walk->in, n);	scatterwalk_advance(&walk->out, n);	scatterwalk_done(&walk->in, 0, nbytes);	scatterwalk_done(&walk->out, 1, nbytes); 	if (nbytes) {		crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?			     CRYPTO_TFM_REQ_MAY_SLEEP : 0);		return skcipher_walk_next(walk);	} 	/* Short-circuit for the common/fast path. */	if (!((unsigned long)walk->buffer | (unsigned long)walk->page))		goto out; 	if (walk->flags & SKCIPHER_WALK_PHYS)		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 err;}EXPORT_SYMBOL_GPL(skcipher_walk_done); void skcipher_walk_complete(struct skcipher_walk *walk, int err){	struct skcipher_walk_buffer *p, *tmp; 	list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {		u8 *data; 		if (err)			goto done; 		data = p->data;		if (!data) {			data = PTR_ALIGN(&p->buffer[0], walk->alignmask + 1);			data = skcipher_get_spot(data, walk->stride);		} 		scatterwalk_copychunks(data, &p->dst, p->len, 1); 		if (offset_in_page(p->data) + p->len + walk->stride >		    PAGE_SIZE)			free_page((unsigned long)p->data); done:		list_del(&p->entry);		kfree(p);	} 	if (!err && 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);}EXPORT_SYMBOL_GPL(skcipher_walk_complete); static void skcipher_queue_write(struct skcipher_walk *walk,				 struct skcipher_walk_buffer *p){	p->dst = walk->out;	list_add_tail(&p->entry, &walk->buffers);} static int skcipher_next_slow(struct skcipher_walk *walk, unsigned int bsize){	bool phys = walk->flags & SKCIPHER_WALK_PHYS;	unsigned alignmask = walk->alignmask;	struct skcipher_walk_buffer *p;	unsigned a;	unsigned n;	u8 *buffer;	void *v; 	if (!phys) {		if (!walk->buffer)			walk->buffer = walk->page;		buffer = walk->buffer;		if (buffer)			goto ok;	} 	/* Start with the minimum alignment of kmalloc. */	a = crypto_tfm_ctx_alignment() - 1;	n = bsize; 	if (phys) {		/* Calculate the minimum alignment of p->buffer. */		a &= (sizeof(*p) ^ (sizeof(*p) - 1)) >> 1;		n += sizeof(*p);	} 	/* Minimum size to align p->buffer by alignmask. */	n += alignmask & ~a; 	/* Minimum size to ensure p->buffer does not straddle a page. */	n += (bsize - 1) & ~(alignmask | a); 	v = kzalloc(n, skcipher_walk_gfp(walk));	if (!v)		return skcipher_walk_done(walk, -ENOMEM); 	if (phys) {		p = v;		p->len = bsize;		skcipher_queue_write(walk, p);		buffer = p->buffer;	} else {		walk->buffer = v;		buffer = v;	} ok:	walk->dst.virt.addr = PTR_ALIGN(buffer, alignmask + 1);	walk->dst.virt.addr = skcipher_get_spot(walk->dst.virt.addr, bsize);	walk->src.virt.addr = walk->dst.virt.addr; 	scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); 	walk->nbytes = bsize;	walk->flags |= SKCIPHER_WALK_SLOW; 	return 0;} static int skcipher_next_copy(struct skcipher_walk *walk){	struct skcipher_walk_buffer *p;	u8 *tmp = walk->page; 	skcipher_map_src(walk);	memcpy(tmp, walk->src.virt.addr, walk->nbytes);	skcipher_unmap_src(walk); 	walk->src.virt.addr = tmp;	walk->dst.virt.addr = tmp; 	if (!(walk->flags & SKCIPHER_WALK_PHYS))		return 0; 	p = kmalloc(sizeof(*p), skcipher_walk_gfp(walk));	if (!p)		return -ENOMEM; 	p->data = walk->page;	p->len = walk->nbytes;	skcipher_queue_write(walk, p); 	if (offset_in_page(walk->page) + walk->nbytes + walk->stride >	    PAGE_SIZE)		walk->page = NULL;	else		walk->page += walk->nbytes; 	return 0;} static int skcipher_next_fast(struct skcipher_walk *walk){	unsigned long diff; 	walk->src.phys.page = scatterwalk_page(&walk->in);	walk->src.phys.offset = offset_in_page(walk->in.offset);	walk->dst.phys.page = scatterwalk_page(&walk->out);	walk->dst.phys.offset = offset_in_page(walk->out.offset); 	if (walk->flags & SKCIPHER_WALK_PHYS)		return 0; 	diff = walk->src.phys.offset - walk->dst.phys.offset;	diff |= walk->src.virt.page - walk->dst.virt.page; 	skcipher_map_src(walk);	walk->dst.virt.addr = walk->src.virt.addr; 	if (diff) {		walk->flags |= SKCIPHER_WALK_DIFF;		skcipher_map_dst(walk);	} 	return 0;} static int skcipher_walk_next(struct skcipher_walk *walk){	unsigned int bsize;	unsigned int n;	int err; 	walk->flags &= ~(SKCIPHER_WALK_SLOW | SKCIPHER_WALK_COPY |			 SKCIPHER_WALK_DIFF); 	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:		err = skcipher_next_slow(walk, bsize);		goto set_phys_lowmem;	} 	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->nbytes = min_t(unsigned, n,				     PAGE_SIZE - offset_in_page(walk->page));		walk->flags |= SKCIPHER_WALK_COPY;		err = skcipher_next_copy(walk);		goto set_phys_lowmem;	} 	walk->nbytes = n; 	return skcipher_next_fast(walk); set_phys_lowmem:	if (!err && (walk->flags & SKCIPHER_WALK_PHYS)) {		walk->src.phys.page = virt_to_page(walk->src.virt.addr);		walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);		walk->src.phys.offset &= PAGE_SIZE - 1;		walk->dst.phys.offset &= PAGE_SIZE - 1;	}	return err;}EXPORT_SYMBOL_GPL(skcipher_walk_next); static int skcipher_copy_iv(struct skcipher_walk *walk){	unsigned a = crypto_tfm_ctx_alignment() - 1;	unsigned alignmask = walk->alignmask;	unsigned ivsize = walk->ivsize;	unsigned bs = walk->stride;	unsigned aligned_bs;	unsigned size;	u8 *iv; 	aligned_bs = ALIGN(bs, alignmask); 	/* Minimum size to align buffer by alignmask. */	size = alignmask & ~a; 	if (walk->flags & SKCIPHER_WALK_PHYS)		size += ivsize;	else {		size += aligned_bs + ivsize; 		/* Minimum size to ensure buffer does not straddle a page. */		size += (bs - 1) & ~(alignmask | a);	} 	walk->buffer = kmalloc(size, skcipher_walk_gfp(walk));	if (!walk->buffer)		return -ENOMEM; 	iv = PTR_ALIGN(walk->buffer, alignmask + 1);	iv = skcipher_get_spot(iv, bs) + aligned_bs; 	walk->iv = memcpy(iv, walk->iv, walk->ivsize);	return 0;} static int skcipher_walk_first(struct skcipher_walk *walk){	walk->nbytes = 0; 	if (WARN_ON_ONCE(in_irq()))		return -EDEADLK; 	if (unlikely(!walk->total))		return 0; 	walk->buffer = NULL;	if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {		int err = skcipher_copy_iv(walk);		if (err)			return err;	} 	walk->page = NULL;	walk->nbytes = walk->total; 	return skcipher_walk_next(walk);} static int skcipher_walk_skcipher(struct skcipher_walk *walk,				  struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 	scatterwalk_start(&walk->in, req->src);	scatterwalk_start(&walk->out, req->dst); 	walk->total = req->cryptlen;	walk->iv = req->iv;	walk->oiv = req->iv; 	walk->flags &= ~SKCIPHER_WALK_SLEEP;	walk->flags |= req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?		       SKCIPHER_WALK_SLEEP : 0; 	walk->blocksize = crypto_skcipher_blocksize(tfm);	walk->stride = crypto_skcipher_walksize(tfm);	walk->ivsize = crypto_skcipher_ivsize(tfm);	walk->alignmask = crypto_skcipher_alignmask(tfm); 	return skcipher_walk_first(walk);} int skcipher_walk_virt(struct skcipher_walk *walk,		       struct skcipher_request *req, bool atomic){	int err; 	walk->flags &= ~SKCIPHER_WALK_PHYS; 	err = skcipher_walk_skcipher(walk, req); 	walk->flags &= atomic ? ~SKCIPHER_WALK_SLEEP : ~0; 	return err;}EXPORT_SYMBOL_GPL(skcipher_walk_virt); void skcipher_walk_atomise(struct skcipher_walk *walk){	walk->flags &= ~SKCIPHER_WALK_SLEEP;}EXPORT_SYMBOL_GPL(skcipher_walk_atomise); int skcipher_walk_async(struct skcipher_walk *walk,			struct skcipher_request *req){	walk->flags |= SKCIPHER_WALK_PHYS; 	INIT_LIST_HEAD(&walk->buffers);

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