linux/crypto/aead.c
Eric Biggers 37db69e0b4 crypto: user - clean up report structure copying
There have been a pretty ridiculous number of issues with initializing
the report structures that are copied to userspace by NETLINK_CRYPTO.
Commit 4473710df1 ("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/

Commit cac5818c25 ("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>
2018-11-09 17:41:39 +08:00

432 lines
10 KiB
C

/*
* AEAD: Authenticated Encryption with Associated Data
*
* This file provides API support for AEAD algorithms.
*
* Copyright (c) 2007-2015 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/geniv.h>
#include <crypto/internal/rng.h>
#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <linux/compiler.h>
#include <net/netlink.h>
#include "internal.h"
static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen)
{
unsigned long alignmask = crypto_aead_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 = crypto_aead_alg(tfm)->setkey(tfm, alignbuffer, keylen);
memset(alignbuffer, 0, keylen);
kfree(buffer);
return ret;
}
int crypto_aead_setkey(struct crypto_aead *tfm,
const u8 *key, unsigned int keylen)
{
unsigned long alignmask = crypto_aead_alignmask(tfm);
int err;
if ((unsigned long)key & alignmask)
err = setkey_unaligned(tfm, key, keylen);
else
err = crypto_aead_alg(tfm)->setkey(tfm, key, keylen);
if (err)
return err;
crypto_aead_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_aead_setkey);
int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
{
int err;
if (authsize > crypto_aead_maxauthsize(tfm))
return -EINVAL;
if (crypto_aead_alg(tfm)->setauthsize) {
err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
if (err)
return err;
}
tfm->authsize = authsize;
return 0;
}
EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_aead *aead = __crypto_aead_cast(tfm);
struct aead_alg *alg = crypto_aead_alg(aead);
alg->exit(aead);
}
static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_aead *aead = __crypto_aead_cast(tfm);
struct aead_alg *alg = crypto_aead_alg(aead);
crypto_aead_set_flags(aead, CRYPTO_TFM_NEED_KEY);
aead->authsize = alg->maxauthsize;
if (alg->exit)
aead->base.exit = crypto_aead_exit_tfm;
if (alg->init)
return alg->init(aead);
return 0;
}
#ifdef CONFIG_NET
static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_aead raead;
struct aead_alg *aead = container_of(alg, struct aead_alg, base);
memset(&raead, 0, sizeof(raead));
strscpy(raead.type, "aead", sizeof(raead.type));
strscpy(raead.geniv, "<none>", sizeof(raead.geniv));
raead.blocksize = alg->cra_blocksize;
raead.maxauthsize = aead->maxauthsize;
raead.ivsize = aead->ivsize;
return nla_put(skb, CRYPTOCFGA_REPORT_AEAD, sizeof(raead), &raead);
}
#else
static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
{
struct aead_alg *aead = container_of(alg, struct aead_alg, base);
seq_printf(m, "type : aead\n");
seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
"yes" : "no");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "ivsize : %u\n", aead->ivsize);
seq_printf(m, "maxauthsize : %u\n", aead->maxauthsize);
seq_printf(m, "geniv : <none>\n");
}
static void crypto_aead_free_instance(struct crypto_instance *inst)
{
struct aead_instance *aead = aead_instance(inst);
if (!aead->free) {
inst->tmpl->free(inst);
return;
}
aead->free(aead);
}
static const struct crypto_type crypto_aead_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_aead_init_tfm,
.free = crypto_aead_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_aead_show,
#endif
.report = crypto_aead_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_AEAD,
.tfmsize = offsetof(struct crypto_aead, base),
};
static int aead_geniv_setkey(struct crypto_aead *tfm,
const u8 *key, unsigned int keylen)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
return crypto_aead_setkey(ctx->child, key, keylen);
}
static int aead_geniv_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
return crypto_aead_setauthsize(ctx->child, authsize);
}
struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
struct rtattr **tb, u32 type, u32 mask)
{
const char *name;
struct crypto_aead_spawn *spawn;
struct crypto_attr_type *algt;
struct aead_instance *inst;
struct aead_alg *alg;
unsigned int ivsize;
unsigned int maxauthsize;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return ERR_CAST(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return ERR_PTR(-EINVAL);
name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(name))
return ERR_CAST(name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
spawn = aead_instance_ctx(inst);
/* Ignore async algorithms if necessary. */
mask |= crypto_requires_sync(algt->type, algt->mask);
crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
err = crypto_grab_aead(spawn, name, type, mask);
if (err)
goto err_free_inst;
alg = crypto_spawn_aead_alg(spawn);
ivsize = crypto_aead_alg_ivsize(alg);
maxauthsize = crypto_aead_alg_maxauthsize(alg);
err = -EINVAL;
if (ivsize < sizeof(u64))
goto err_drop_alg;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"%s(%s)", tmpl->name, alg->base.cra_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_drop_alg;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_drop_alg;
inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
inst->alg.setkey = aead_geniv_setkey;
inst->alg.setauthsize = aead_geniv_setauthsize;
inst->alg.ivsize = ivsize;
inst->alg.maxauthsize = maxauthsize;
out:
return inst;
err_drop_alg:
crypto_drop_aead(spawn);
err_free_inst:
kfree(inst);
inst = ERR_PTR(err);
goto out;
}
EXPORT_SYMBOL_GPL(aead_geniv_alloc);
void aead_geniv_free(struct aead_instance *inst)
{
crypto_drop_aead(aead_instance_ctx(inst));
kfree(inst);
}
EXPORT_SYMBOL_GPL(aead_geniv_free);
int aead_init_geniv(struct crypto_aead *aead)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
struct aead_instance *inst = aead_alg_instance(aead);
struct crypto_aead *child;
int err;
spin_lock_init(&ctx->lock);
err = crypto_get_default_rng();
if (err)
goto out;
err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
crypto_aead_ivsize(aead));
crypto_put_default_rng();
if (err)
goto out;
ctx->sknull = crypto_get_default_null_skcipher();
err = PTR_ERR(ctx->sknull);
if (IS_ERR(ctx->sknull))
goto out;
child = crypto_spawn_aead(aead_instance_ctx(inst));
err = PTR_ERR(child);
if (IS_ERR(child))
goto drop_null;
ctx->child = child;
crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
sizeof(struct aead_request));
err = 0;
out:
return err;
drop_null:
crypto_put_default_null_skcipher();
goto out;
}
EXPORT_SYMBOL_GPL(aead_init_geniv);
void aead_exit_geniv(struct crypto_aead *tfm)
{
struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_aead(ctx->child);
crypto_put_default_null_skcipher();
}
EXPORT_SYMBOL_GPL(aead_exit_geniv);
int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
u32 type, u32 mask)
{
spawn->base.frontend = &crypto_aead_type;
return crypto_grab_spawn(&spawn->base, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_aead);
struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_aead);
static int aead_prepare_alg(struct aead_alg *alg)
{
struct crypto_alg *base = &alg->base;
if (max3(alg->maxauthsize, alg->ivsize, alg->chunksize) >
PAGE_SIZE / 8)
return -EINVAL;
if (!alg->chunksize)
alg->chunksize = base->cra_blocksize;
base->cra_type = &crypto_aead_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_AEAD;
return 0;
}
int crypto_register_aead(struct aead_alg *alg)
{
struct crypto_alg *base = &alg->base;
int err;
err = aead_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_aead);
void crypto_unregister_aead(struct aead_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_aead);
int crypto_register_aeads(struct aead_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_aead(&algs[i]);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_aead(&algs[i]);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_aeads);
void crypto_unregister_aeads(struct aead_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_aead(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_aeads);
int aead_register_instance(struct crypto_template *tmpl,
struct aead_instance *inst)
{
int err;
err = aead_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, aead_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(aead_register_instance);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");