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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 18:09:57 +00:00
![Eric Biggers](/assets/img/avatar_default.png)
There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit4473710df1
("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commitcac5818c25
("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
484 lines
13 KiB
C
484 lines
13 KiB
C
/*
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* Asynchronous block chaining cipher operations.
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*
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* This is the asynchronous version of blkcipher.c indicating completion
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* via a callback.
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*
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* Copyright (c) 2006 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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#include <crypto/internal/skcipher.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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#include <linux/cryptouser.h>
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#include <linux/compiler.h>
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#include <net/netlink.h>
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#include <crypto/scatterwalk.h>
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#include "internal.h"
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struct ablkcipher_buffer {
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struct list_head entry;
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struct scatter_walk dst;
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unsigned int len;
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void *data;
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};
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enum {
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ABLKCIPHER_WALK_SLOW = 1 << 0,
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};
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static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
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{
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scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
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}
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void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
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{
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struct ablkcipher_buffer *p, *tmp;
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list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
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ablkcipher_buffer_write(p);
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list_del(&p->entry);
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kfree(p);
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}
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}
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EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
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static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
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struct ablkcipher_buffer *p)
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{
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p->dst = walk->out;
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list_add_tail(&p->entry, &walk->buffers);
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}
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/* Get a spot of the specified length that does not straddle a page.
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* The caller needs to ensure that there is enough space for this operation.
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*/
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static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
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{
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u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
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return max(start, end_page);
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}
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static inline void ablkcipher_done_slow(struct ablkcipher_walk *walk,
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unsigned int n)
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{
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for (;;) {
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unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
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if (len_this_page > n)
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len_this_page = n;
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scatterwalk_advance(&walk->out, n);
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if (n == len_this_page)
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break;
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n -= len_this_page;
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scatterwalk_start(&walk->out, sg_next(walk->out.sg));
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}
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}
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static inline void ablkcipher_done_fast(struct ablkcipher_walk *walk,
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unsigned int n)
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{
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scatterwalk_advance(&walk->in, n);
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scatterwalk_advance(&walk->out, n);
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}
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static int ablkcipher_walk_next(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk);
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int ablkcipher_walk_done(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk, int err)
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{
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struct crypto_tfm *tfm = req->base.tfm;
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unsigned int n; /* bytes processed */
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bool more;
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if (unlikely(err < 0))
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goto finish;
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n = walk->nbytes - err;
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walk->total -= n;
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more = (walk->total != 0);
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if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW))) {
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ablkcipher_done_fast(walk, n);
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} else {
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if (WARN_ON(err)) {
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/* unexpected case; didn't process all bytes */
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err = -EINVAL;
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goto finish;
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}
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ablkcipher_done_slow(walk, n);
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}
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scatterwalk_done(&walk->in, 0, more);
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scatterwalk_done(&walk->out, 1, more);
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if (more) {
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crypto_yield(req->base.flags);
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return ablkcipher_walk_next(req, walk);
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}
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err = 0;
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finish:
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walk->nbytes = 0;
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if (walk->iv != req->info)
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memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
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kfree(walk->iv_buffer);
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return err;
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}
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EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
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static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk,
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unsigned int bsize,
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unsigned int alignmask,
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void **src_p, void **dst_p)
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{
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unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
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struct ablkcipher_buffer *p;
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void *src, *dst, *base;
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unsigned int n;
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n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
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n += (aligned_bsize * 3 - (alignmask + 1) +
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(alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
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p = kmalloc(n, GFP_ATOMIC);
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if (!p)
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return ablkcipher_walk_done(req, walk, -ENOMEM);
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base = p + 1;
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dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
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src = dst = ablkcipher_get_spot(dst, bsize);
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p->len = bsize;
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p->data = dst;
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scatterwalk_copychunks(src, &walk->in, bsize, 0);
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ablkcipher_queue_write(walk, p);
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walk->nbytes = bsize;
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walk->flags |= ABLKCIPHER_WALK_SLOW;
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*src_p = src;
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*dst_p = dst;
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return 0;
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}
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static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
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struct crypto_tfm *tfm,
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unsigned int alignmask)
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{
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unsigned bs = walk->blocksize;
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unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
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unsigned aligned_bs = ALIGN(bs, alignmask + 1);
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unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
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(alignmask + 1);
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u8 *iv;
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size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
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walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
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if (!walk->iv_buffer)
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return -ENOMEM;
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iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
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iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
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iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
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iv = ablkcipher_get_spot(iv, ivsize);
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walk->iv = memcpy(iv, walk->iv, ivsize);
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return 0;
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}
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static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk)
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{
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walk->src.page = scatterwalk_page(&walk->in);
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walk->src.offset = offset_in_page(walk->in.offset);
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walk->dst.page = scatterwalk_page(&walk->out);
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walk->dst.offset = offset_in_page(walk->out.offset);
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return 0;
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}
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static int ablkcipher_walk_next(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk)
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{
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struct crypto_tfm *tfm = req->base.tfm;
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unsigned int alignmask, bsize, n;
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void *src, *dst;
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int err;
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alignmask = crypto_tfm_alg_alignmask(tfm);
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n = walk->total;
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if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
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req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
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return ablkcipher_walk_done(req, walk, -EINVAL);
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}
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walk->flags &= ~ABLKCIPHER_WALK_SLOW;
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src = dst = NULL;
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bsize = min(walk->blocksize, n);
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n = scatterwalk_clamp(&walk->in, n);
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n = scatterwalk_clamp(&walk->out, n);
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if (n < bsize ||
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!scatterwalk_aligned(&walk->in, alignmask) ||
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!scatterwalk_aligned(&walk->out, alignmask)) {
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err = ablkcipher_next_slow(req, walk, bsize, alignmask,
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&src, &dst);
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goto set_phys_lowmem;
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}
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walk->nbytes = n;
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return ablkcipher_next_fast(req, walk);
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set_phys_lowmem:
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if (err >= 0) {
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walk->src.page = virt_to_page(src);
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walk->dst.page = virt_to_page(dst);
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walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
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walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
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}
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return err;
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}
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static int ablkcipher_walk_first(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk)
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{
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struct crypto_tfm *tfm = req->base.tfm;
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unsigned int alignmask;
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alignmask = crypto_tfm_alg_alignmask(tfm);
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if (WARN_ON_ONCE(in_irq()))
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return -EDEADLK;
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walk->iv = req->info;
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walk->nbytes = walk->total;
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if (unlikely(!walk->total))
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return 0;
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walk->iv_buffer = NULL;
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if (unlikely(((unsigned long)walk->iv & alignmask))) {
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int err = ablkcipher_copy_iv(walk, tfm, alignmask);
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if (err)
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return err;
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}
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scatterwalk_start(&walk->in, walk->in.sg);
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scatterwalk_start(&walk->out, walk->out.sg);
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return ablkcipher_walk_next(req, walk);
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}
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int ablkcipher_walk_phys(struct ablkcipher_request *req,
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struct ablkcipher_walk *walk)
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{
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walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
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return ablkcipher_walk_first(req, walk);
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}
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EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
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static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
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unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
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int ret;
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u8 *buffer, *alignbuffer;
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unsigned long absize;
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absize = keylen + alignmask;
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buffer = kmalloc(absize, GFP_ATOMIC);
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if (!buffer)
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return -ENOMEM;
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alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
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memcpy(alignbuffer, key, keylen);
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ret = cipher->setkey(tfm, alignbuffer, keylen);
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memset(alignbuffer, 0, keylen);
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kfree(buffer);
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return ret;
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}
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static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
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unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
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if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
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crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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if ((unsigned long)key & alignmask)
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return setkey_unaligned(tfm, key, keylen);
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return cipher->setkey(tfm, key, keylen);
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}
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static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
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u32 mask)
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{
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return alg->cra_ctxsize;
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}
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static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
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u32 mask)
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{
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struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
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struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
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if (alg->ivsize > PAGE_SIZE / 8)
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return -EINVAL;
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crt->setkey = setkey;
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crt->encrypt = alg->encrypt;
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crt->decrypt = alg->decrypt;
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crt->base = __crypto_ablkcipher_cast(tfm);
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crt->ivsize = alg->ivsize;
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return 0;
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}
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#ifdef CONFIG_NET
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static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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struct crypto_report_blkcipher rblkcipher;
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memset(&rblkcipher, 0, sizeof(rblkcipher));
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strscpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
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strscpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
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sizeof(rblkcipher.geniv));
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rblkcipher.blocksize = alg->cra_blocksize;
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rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
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rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
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rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
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return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
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sizeof(rblkcipher), &rblkcipher);
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}
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#else
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static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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return -ENOSYS;
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}
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#endif
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static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
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__maybe_unused;
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static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
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{
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struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
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seq_printf(m, "type : ablkcipher\n");
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seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
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"yes" : "no");
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seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
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seq_printf(m, "min keysize : %u\n", ablkcipher->min_keysize);
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seq_printf(m, "max keysize : %u\n", ablkcipher->max_keysize);
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seq_printf(m, "ivsize : %u\n", ablkcipher->ivsize);
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seq_printf(m, "geniv : %s\n", ablkcipher->geniv ?: "<default>");
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}
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const struct crypto_type crypto_ablkcipher_type = {
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.ctxsize = crypto_ablkcipher_ctxsize,
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.init = crypto_init_ablkcipher_ops,
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#ifdef CONFIG_PROC_FS
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.show = crypto_ablkcipher_show,
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#endif
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.report = crypto_ablkcipher_report,
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};
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EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
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static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
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u32 mask)
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{
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struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
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struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
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if (alg->ivsize > PAGE_SIZE / 8)
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return -EINVAL;
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crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
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alg->setkey : setkey;
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crt->encrypt = alg->encrypt;
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crt->decrypt = alg->decrypt;
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crt->base = __crypto_ablkcipher_cast(tfm);
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crt->ivsize = alg->ivsize;
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return 0;
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}
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#ifdef CONFIG_NET
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static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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struct crypto_report_blkcipher rblkcipher;
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memset(&rblkcipher, 0, sizeof(rblkcipher));
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strscpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
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strscpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
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sizeof(rblkcipher.geniv));
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rblkcipher.blocksize = alg->cra_blocksize;
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rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
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rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
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rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
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return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
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sizeof(rblkcipher), &rblkcipher);
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}
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#else
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static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
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{
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return -ENOSYS;
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}
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#endif
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static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
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__maybe_unused;
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static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
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{
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struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
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seq_printf(m, "type : givcipher\n");
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seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
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"yes" : "no");
|
|
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
|
|
seq_printf(m, "min keysize : %u\n", ablkcipher->min_keysize);
|
|
seq_printf(m, "max keysize : %u\n", ablkcipher->max_keysize);
|
|
seq_printf(m, "ivsize : %u\n", ablkcipher->ivsize);
|
|
seq_printf(m, "geniv : %s\n", ablkcipher->geniv ?: "<built-in>");
|
|
}
|
|
|
|
const struct crypto_type crypto_givcipher_type = {
|
|
.ctxsize = crypto_ablkcipher_ctxsize,
|
|
.init = crypto_init_givcipher_ops,
|
|
#ifdef CONFIG_PROC_FS
|
|
.show = crypto_givcipher_show,
|
|
#endif
|
|
.report = crypto_givcipher_report,
|
|
};
|
|
EXPORT_SYMBOL_GPL(crypto_givcipher_type);
|