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linux_dsm_epyc7002/crypto/blkcipher.c
Eric Biggers 0868def3e4 crypto: blkcipher - fix crash flushing dcache in error path 
Like the skcipher_walk case:

scatterwalk_done() is only meant to be called after a nonzero number of
bytes have been processed, since scatterwalk_pagedone() will flush the
dcache of the *previous* page.  But in the error case of
blkcipher_walk_done(), e.g. if the input wasn't an integer number of
blocks, scatterwalk_done() was actually called after advancing 0 bytes.
This caused a crash ("BUG: unable to handle kernel paging request")
during '!PageSlab(page)' on architectures like arm and arm64 that define
ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, provided that the input was
page-aligned as in that case walk->offset == 0.

Fix it by reorganizing blkcipher_walk_done() to skip the
scatterwalk_advance() and scatterwalk_done() if an error has occurred.

This bug was found by syzkaller fuzzing.

Reproducer, assuming ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE:

	#include <linux/if_alg.h>
	#include <sys/socket.h>
	#include <unistd.h>

	int main()
	{
		struct sockaddr_alg addr = {
			.salg_type = "skcipher",
			.salg_name = "ecb(aes-generic)",
		};
		char buffer[4096] __attribute__((aligned(4096))) = { 0 };
		int fd;

		fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
		bind(fd, (void *)&addr, sizeof(addr));
		setsockopt(fd, SOL_ALG, ALG_SET_KEY, buffer, 16);
		fd = accept(fd, NULL, NULL);
		write(fd, buffer, 15);
		read(fd, buffer, 15);
	}

Reported-by: Liu Chao <liuchao741@huawei.com>
Fixes: 5cde0af2a9 ("[CRYPTO] cipher: Added block cipher type")
Cc: <stable@vger.kernel.org> # v2.6.19+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-08-03 18:06:04 +08:00

560 lines
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/*
* Block chaining 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) 2006 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/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cryptouser.h>
#include <linux/compiler.h>
#include <net/netlink.h>
#include "internal.h"
enum {
BLKCIPHER_WALK_PHYS = 1 << 0,
BLKCIPHER_WALK_SLOW = 1 << 1,
BLKCIPHER_WALK_COPY = 1 << 2,
BLKCIPHER_WALK_DIFF = 1 << 3,
};
static int blkcipher_walk_next(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
static int blkcipher_walk_first(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
static inline void blkcipher_map_src(struct blkcipher_walk *walk)
{
walk->src.virt.addr = scatterwalk_map(&walk->in);
}
static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
{
walk->dst.virt.addr = scatterwalk_map(&walk->out);
}
static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
{
scatterwalk_unmap(walk->src.virt.addr);
}
static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
{
scatterwalk_unmap(walk->dst.virt.addr);
}
/* 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 *blkcipher_get_spot(u8 *start, unsigned int len)
{
u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
return max(start, end_page);
}
static inline void blkcipher_done_slow(struct blkcipher_walk *walk,
unsigned int bsize)
{
u8 *addr;
addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
addr = blkcipher_get_spot(addr, bsize);
scatterwalk_copychunks(addr, &walk->out, bsize, 1);
}
static inline void blkcipher_done_fast(struct blkcipher_walk *walk,
unsigned int n)
{
if (walk->flags & BLKCIPHER_WALK_COPY) {
blkcipher_map_dst(walk);
memcpy(walk->dst.virt.addr, walk->page, n);
blkcipher_unmap_dst(walk);
} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
if (walk->flags & BLKCIPHER_WALK_DIFF)
blkcipher_unmap_dst(walk);
blkcipher_unmap_src(walk);
}
scatterwalk_advance(&walk->in, n);
scatterwalk_advance(&walk->out, n);
}
int blkcipher_walk_done(struct blkcipher_desc *desc,
struct blkcipher_walk *walk, int err)
{
unsigned int n; /* bytes processed */
bool more;
if (unlikely(err < 0))
goto finish;
n = walk->nbytes - err;
walk->total -= n;
more = (walk->total != 0);
if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) {
blkcipher_done_fast(walk, n);
} else {
if (WARN_ON(err)) {
/* unexpected case; didn't process all bytes */
err = -EINVAL;
goto finish;
}
blkcipher_done_slow(walk, n);
}
scatterwalk_done(&walk->in, 0, more);
scatterwalk_done(&walk->out, 1, more);
if (more) {
crypto_yield(desc->flags);
return blkcipher_walk_next(desc, walk);
}
err = 0;
finish:
walk->nbytes = 0;
if (walk->iv != desc->info)
memcpy(desc->info, walk->iv, walk->ivsize);
if (walk->buffer != walk->page)
kfree(walk->buffer);
if (walk->page)
free_page((unsigned long)walk->page);
return err;
}
EXPORT_SYMBOL_GPL(blkcipher_walk_done);
static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
unsigned int bsize,
unsigned int alignmask)
{
unsigned int n;
unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
if (walk->buffer)
goto ok;
walk->buffer = walk->page;
if (walk->buffer)
goto ok;
n = aligned_bsize * 3 - (alignmask + 1) +
(alignmask & ~(crypto_tfm_ctx_alignment() - 1));
walk->buffer = kmalloc(n, GFP_ATOMIC);
if (!walk->buffer)
return blkcipher_walk_done(desc, walk, -ENOMEM);
ok:
walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
alignmask + 1);
walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
aligned_bsize, bsize);
scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
walk->nbytes = bsize;
walk->flags |= BLKCIPHER_WALK_SLOW;
return 0;
}
static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
{
u8 *tmp = walk->page;
blkcipher_map_src(walk);
memcpy(tmp, walk->src.virt.addr, walk->nbytes);
blkcipher_unmap_src(walk);
walk->src.virt.addr = tmp;
walk->dst.virt.addr = tmp;
return 0;
}
static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
struct blkcipher_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 & BLKCIPHER_WALK_PHYS)
return 0;
diff = walk->src.phys.offset - walk->dst.phys.offset;
diff |= walk->src.virt.page - walk->dst.virt.page;
blkcipher_map_src(walk);
walk->dst.virt.addr = walk->src.virt.addr;
if (diff) {
walk->flags |= BLKCIPHER_WALK_DIFF;
blkcipher_map_dst(walk);
}
return 0;
}
static int blkcipher_walk_next(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
unsigned int bsize;
unsigned int n;
int err;
n = walk->total;
if (unlikely(n < walk->cipher_blocksize)) {
desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return blkcipher_walk_done(desc, walk, -EINVAL);
}
bsize = min(walk->walk_blocksize, n);
walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
BLKCIPHER_WALK_DIFF);
if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
!scatterwalk_aligned(&walk->out, walk->alignmask)) {
walk->flags |= BLKCIPHER_WALK_COPY;
if (!walk->page) {
walk->page = (void *)__get_free_page(GFP_ATOMIC);
if (!walk->page)
n = 0;
}
}
n = scatterwalk_clamp(&walk->in, n);
n = scatterwalk_clamp(&walk->out, n);
if (unlikely(n < bsize)) {
err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
goto set_phys_lowmem;
}
walk->nbytes = n;
if (walk->flags & BLKCIPHER_WALK_COPY) {
err = blkcipher_next_copy(walk);
goto set_phys_lowmem;
}
return blkcipher_next_fast(desc, walk);
set_phys_lowmem:
if (walk->flags & BLKCIPHER_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;
}
static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
{
unsigned bs = walk->walk_blocksize;
unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
unsigned int size = aligned_bs * 2 +
walk->ivsize + max(aligned_bs, walk->ivsize) -
(walk->alignmask + 1);
u8 *iv;
size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
walk->buffer = kmalloc(size, GFP_ATOMIC);
if (!walk->buffer)
return -ENOMEM;
iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
iv = blkcipher_get_spot(iv, bs) + aligned_bs;
iv = blkcipher_get_spot(iv, bs) + aligned_bs;
iv = blkcipher_get_spot(iv, walk->ivsize);
walk->iv = memcpy(iv, walk->iv, walk->ivsize);
return 0;
}
int blkcipher_walk_virt(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
walk->flags &= ~BLKCIPHER_WALK_PHYS;
walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
walk->cipher_blocksize = walk->walk_blocksize;
walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
int blkcipher_walk_phys(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
walk->flags |= BLKCIPHER_WALK_PHYS;
walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
walk->cipher_blocksize = walk->walk_blocksize;
walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
static int blkcipher_walk_first(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;
walk->iv = desc->info;
walk->nbytes = walk->total;
if (unlikely(!walk->total))
return 0;
walk->buffer = NULL;
if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
int err = blkcipher_copy_iv(walk);
if (err)
return err;
}
scatterwalk_start(&walk->in, walk->in.sg);
scatterwalk_start(&walk->out, walk->out.sg);
walk->page = NULL;
return blkcipher_walk_next(desc, walk);
}
int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
unsigned int blocksize)
{
walk->flags &= ~BLKCIPHER_WALK_PHYS;
walk->walk_blocksize = blocksize;
walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_aead *tfm,
unsigned int blocksize)
{
walk->flags &= ~BLKCIPHER_WALK_PHYS;
walk->walk_blocksize = blocksize;
walk->cipher_blocksize = crypto_aead_blocksize(tfm);
walk->ivsize = crypto_aead_ivsize(tfm);
walk->alignmask = crypto_aead_alignmask(tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
int ret;
u8 *buffer, *alignbuffer;
unsigned long absize;
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);
memset(alignbuffer, 0, keylen);
kfree(buffer);
return ret;
}
static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}
if ((unsigned long)key & alignmask)
return setkey_unaligned(tfm, key, keylen);
return cipher->setkey(tfm, key, keylen);
}
static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int keylen)
{
return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
}
static int async_encrypt(struct ablkcipher_request *req)
{
struct crypto_tfm *tfm = req->base.tfm;
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
struct blkcipher_desc desc = {
.tfm = __crypto_blkcipher_cast(tfm),
.info = req->info,
.flags = req->base.flags,
};
return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
}
static int async_decrypt(struct ablkcipher_request *req)
{
struct crypto_tfm *tfm = req->base.tfm;
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
struct blkcipher_desc desc = {
.tfm = __crypto_blkcipher_cast(tfm),
.info = req->info,
.flags = req->base.flags,
};
return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
}
static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
u32 mask)
{
struct blkcipher_alg *cipher = &alg->cra_blkcipher;
unsigned int len = alg->cra_ctxsize;
if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
cipher->ivsize) {
len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
len += cipher->ivsize;
}
return len;
}
static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
{
struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
crt->setkey = async_setkey;
crt->encrypt = async_encrypt;
crt->decrypt = async_decrypt;
crt->base = __crypto_ablkcipher_cast(tfm);
crt->ivsize = alg->ivsize;
return 0;
}
static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
{
struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
unsigned long addr;
crt->setkey = setkey;
crt->encrypt = alg->encrypt;
crt->decrypt = alg->decrypt;
addr = (unsigned long)crypto_tfm_ctx(tfm);
addr = ALIGN(addr, align);
addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
crt->iv = (void *)addr;
return 0;
}
static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
if (alg->ivsize > PAGE_SIZE / 8)
return -EINVAL;
if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
return crypto_init_blkcipher_ops_sync(tfm);
else
return crypto_init_blkcipher_ops_async(tfm);
}
#ifdef CONFIG_NET
static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_blkcipher rblkcipher;
strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
sizeof(rblkcipher.geniv));
rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
rblkcipher.blocksize = alg->cra_blocksize;
rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
sizeof(struct crypto_report_blkcipher), &rblkcipher))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_printf(m, "type : blkcipher\n");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize);
seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize);
seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize);
seq_printf(m, "geniv : %s\n", alg->cra_blkcipher.geniv ?:
"<default>");
}
const struct crypto_type crypto_blkcipher_type = {
.ctxsize = crypto_blkcipher_ctxsize,
.init = crypto_init_blkcipher_ops,
#ifdef CONFIG_PROC_FS
.show = crypto_blkcipher_show,
#endif
.report = crypto_blkcipher_report,
};
EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic block chaining cipher type");
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