8ec970d856
When I backed out of using the generic sg chaining (as it isn't currently portable) and introduced scatterwalk_sg_chain/scatterwalk_sg_next I left out the sg_is_last check in the latter. This causes it to potentially dereference beyond the end of the sg array. As most uses of scatterwalk_sg_next are bound by an overall length, this only affected the chaining code in authenc and eseqiv. Thanks to Patrick McHardy for identifying this problem. This patch also clears the "last" bit on the head of the chained list as it's no longer last. This also went missing in scatterwalk_sg_chain and is present in sg_chain. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/*
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* Cryptographic scatter and gather helpers.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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* Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
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* Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _CRYPTO_SCATTERWALK_H
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#define _CRYPTO_SCATTERWALK_H
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#include <asm/kmap_types.h>
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#include <crypto/algapi.h>
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#include <linux/hardirq.h>
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#include <linux/highmem.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/scatterlist.h>
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#include <linux/sched.h>
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static inline enum km_type crypto_kmap_type(int out)
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{
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enum km_type type;
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if (in_softirq())
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type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
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else
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type = out * (KM_USER1 - KM_USER0) + KM_USER0;
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return type;
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}
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static inline void *crypto_kmap(struct page *page, int out)
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{
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return kmap_atomic(page, crypto_kmap_type(out));
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}
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static inline void crypto_kunmap(void *vaddr, int out)
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{
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kunmap_atomic(vaddr, crypto_kmap_type(out));
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}
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static inline void crypto_yield(u32 flags)
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{
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if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
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cond_resched();
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}
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static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
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struct scatterlist *sg2)
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{
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sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
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sg1[num - 1].page_link &= ~0x02;
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}
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static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
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{
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if (sg_is_last(sg))
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return NULL;
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return (++sg)->length ? sg : (void *)sg_page(sg);
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}
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static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
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struct scatter_walk *walk_out)
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{
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return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
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(int)(walk_in->offset - walk_out->offset));
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}
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static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
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{
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unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
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unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
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return len_this_page > len ? len : len_this_page;
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}
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static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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unsigned int len_this_page = scatterwalk_pagelen(walk);
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return nbytes > len_this_page ? len_this_page : nbytes;
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}
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static inline void scatterwalk_advance(struct scatter_walk *walk,
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unsigned int nbytes)
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{
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walk->offset += nbytes;
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}
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static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
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unsigned int alignmask)
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{
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return !(walk->offset & alignmask);
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}
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static inline struct page *scatterwalk_page(struct scatter_walk *walk)
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{
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return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
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}
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static inline void scatterwalk_unmap(void *vaddr, int out)
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{
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crypto_kunmap(vaddr, out);
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}
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void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
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void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
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size_t nbytes, int out);
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void *scatterwalk_map(struct scatter_walk *walk, int out);
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void scatterwalk_done(struct scatter_walk *walk, int out, int more);
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void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
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unsigned int start, unsigned int nbytes, int out);
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#endif /* _CRYPTO_SCATTERWALK_H */
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