WSL2-Linux-Kernel/crypto/shash.c

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17 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Synchronous Cryptographic Hash operations.
*
* Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <crypto/scatterwalk.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "hash.h"
#define MAX_SHASH_ALIGNMASK 63
static const struct crypto_type crypto_shash_type;
static inline struct crypto_istat_hash *shash_get_stat(struct shash_alg *alg)
{
return hash_get_stat(&alg->halg);
}
static inline int crypto_shash_errstat(struct shash_alg *alg, int err)
{
return crypto_hash_errstat(&alg->halg, err);
}
int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
return -ENOSYS;
}
EXPORT_SYMBOL_GPL(shash_no_setkey);
static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned long absize;
u8 *buffer, *alignbuffer;
int err;
absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
buffer = kmalloc(absize, GFP_ATOMIC);
if (!buffer)
return -ENOMEM;
alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
memcpy(alignbuffer, key, keylen);
err = shash->setkey(tfm, alignbuffer, keylen);
mm, treewide: rename kzfree() to kfree_sensitive() As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 09:18:13 +03:00
kfree_sensitive(buffer);
return err;
}
static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg)
{
if (crypto_shash_alg_needs_key(alg))
crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
}
int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
int err;
if ((unsigned long)key & alignmask)
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
err = shash_setkey_unaligned(tfm, key, keylen);
else
err = shash->setkey(tfm, key, keylen);
if (unlikely(err)) {
shash_set_needkey(tfm, shash);
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
return err;
}
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_shash_setkey);
static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
unsigned int unaligned_len = alignmask + 1 -
((unsigned long)data & alignmask);
/*
* We cannot count on __aligned() working for large values:
* https://patchwork.kernel.org/patch/9507697/
*/
u8 ubuf[MAX_SHASH_ALIGNMASK * 2];
u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
int err;
if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf)))
return -EINVAL;
if (unaligned_len > len)
unaligned_len = len;
memcpy(buf, data, unaligned_len);
err = shash->update(desc, buf, unaligned_len);
memset(buf, 0, unaligned_len);
return err ?:
shash->update(desc, data + unaligned_len, len - unaligned_len);
}
int crypto_shash_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
int err;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
atomic64_add(len, &shash_get_stat(shash)->hash_tlen);
if ((unsigned long)data & alignmask)
err = shash_update_unaligned(desc, data, len);
else
err = shash->update(desc, data, len);
return crypto_shash_errstat(shash, err);
}
EXPORT_SYMBOL_GPL(crypto_shash_update);
static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
unsigned long alignmask = crypto_shash_alignmask(tfm);
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned int ds = crypto_shash_digestsize(tfm);
/*
* We cannot count on __aligned() working for large values:
* https://patchwork.kernel.org/patch/9507697/
*/
u8 ubuf[MAX_SHASH_ALIGNMASK + HASH_MAX_DIGESTSIZE];
u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
int err;
if (WARN_ON(buf + ds > ubuf + sizeof(ubuf)))
return -EINVAL;
err = shash->final(desc, buf);
if (err)
goto out;
memcpy(out, buf, ds);
out:
memset(buf, 0, ds);
return err;
}
int crypto_shash_final(struct shash_desc *desc, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
int err;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
atomic64_inc(&shash_get_stat(shash)->hash_cnt);
if ((unsigned long)out & alignmask)
err = shash_final_unaligned(desc, out);
else
err = shash->final(desc, out);
return crypto_shash_errstat(shash, err);
}
EXPORT_SYMBOL_GPL(crypto_shash_final);
static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return shash_update_unaligned(desc, data, len) ?:
shash_final_unaligned(desc, out);
}
int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
int err;
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_hash *istat = shash_get_stat(shash);
atomic64_inc(&istat->hash_cnt);
atomic64_add(len, &istat->hash_tlen);
}
if (((unsigned long)data | (unsigned long)out) & alignmask)
err = shash_finup_unaligned(desc, data, len, out);
else
err = shash->finup(desc, data, len, out);
return crypto_shash_errstat(shash, err);
}
EXPORT_SYMBOL_GPL(crypto_shash_finup);
static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return crypto_shash_init(desc) ?:
shash_update_unaligned(desc, data, len) ?:
shash_final_unaligned(desc, out);
}
int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
struct crypto_shash *tfm = desc->tfm;
struct shash_alg *shash = crypto_shash_alg(tfm);
unsigned long alignmask = crypto_shash_alignmask(tfm);
int err;
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_hash *istat = shash_get_stat(shash);
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
atomic64_inc(&istat->hash_cnt);
atomic64_add(len, &istat->hash_tlen);
}
if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
err = -ENOKEY;
else if (((unsigned long)data | (unsigned long)out) & alignmask)
err = shash_digest_unaligned(desc, data, len, out);
else
err = shash->digest(desc, data, len, out);
return crypto_shash_errstat(shash, err);
}
EXPORT_SYMBOL_GPL(crypto_shash_digest);
int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
unsigned int len, u8 *out)
{
SHASH_DESC_ON_STACK(desc, tfm);
int err;
desc->tfm = tfm;
err = crypto_shash_digest(desc, data, len, out);
shash_desc_zero(desc);
return err;
}
EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);
static int shash_default_export(struct shash_desc *desc, void *out)
{
memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
return 0;
}
static int shash_default_import(struct shash_desc *desc, const void *in)
{
memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
return 0;
}
static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
{
struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
return crypto_shash_setkey(*ctx, key, keylen);
}
static int shash_async_init(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return crypto_shash_init(desc);
}
int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
{
struct crypto_hash_walk walk;
int nbytes;
for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
nbytes = crypto_hash_walk_done(&walk, nbytes))
nbytes = crypto_shash_update(desc, walk.data, nbytes);
return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_update);
static int shash_async_update(struct ahash_request *req)
{
return shash_ahash_update(req, ahash_request_ctx(req));
}
static int shash_async_final(struct ahash_request *req)
{
return crypto_shash_final(ahash_request_ctx(req), req->result);
}
int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
{
struct crypto_hash_walk walk;
int nbytes;
nbytes = crypto_hash_walk_first(req, &walk);
if (!nbytes)
return crypto_shash_final(desc, req->result);
do {
nbytes = crypto_hash_walk_last(&walk) ?
crypto_shash_finup(desc, walk.data, nbytes,
req->result) :
crypto_shash_update(desc, walk.data, nbytes);
nbytes = crypto_hash_walk_done(&walk, nbytes);
} while (nbytes > 0);
return nbytes;
}
EXPORT_SYMBOL_GPL(shash_ahash_finup);
static int shash_async_finup(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return shash_ahash_finup(req, desc);
}
int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
{
unsigned int nbytes = req->nbytes;
struct scatterlist *sg;
unsigned int offset;
int err;
if (nbytes &&
(sg = req->src, offset = sg->offset,
nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
void *data;
data = kmap_local_page(sg_page(sg));
err = crypto_shash_digest(desc, data + offset, nbytes,
req->result);
kunmap_local(data);
} else
err = crypto_shash_init(desc) ?:
shash_ahash_finup(req, desc);
return err;
}
EXPORT_SYMBOL_GPL(shash_ahash_digest);
static int shash_async_digest(struct ahash_request *req)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return shash_ahash_digest(req, desc);
}
static int shash_async_export(struct ahash_request *req, void *out)
{
return crypto_shash_export(ahash_request_ctx(req), out);
}
static int shash_async_import(struct ahash_request *req, const void *in)
{
struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
struct shash_desc *desc = ahash_request_ctx(req);
desc->tfm = *ctx;
return crypto_shash_import(desc, in);
}
static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
crypto_free_shash(*ctx);
}
int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
{
struct crypto_alg *calg = tfm->__crt_alg;
struct shash_alg *alg = __crypto_shash_alg(calg);
struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
struct crypto_shash *shash;
if (!crypto_mod_get(calg))
return -EAGAIN;
shash = crypto_create_tfm(calg, &crypto_shash_type);
if (IS_ERR(shash)) {
crypto_mod_put(calg);
return PTR_ERR(shash);
}
*ctx = shash;
tfm->exit = crypto_exit_shash_ops_async;
crt->init = shash_async_init;
crt->update = shash_async_update;
crt->final = shash_async_final;
crt->finup = shash_async_finup;
crt->digest = shash_async_digest;
if (crypto_shash_alg_has_setkey(alg))
crt->setkey = shash_async_setkey;
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
CRYPTO_TFM_NEED_KEY);
crt->export = shash_async_export;
crt->import = shash_async_import;
crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
return 0;
}
static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_shash *hash = __crypto_shash_cast(tfm);
struct shash_alg *alg = crypto_shash_alg(hash);
alg->exit_tfm(hash);
}
static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_shash *hash = __crypto_shash_cast(tfm);
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
struct shash_alg *alg = crypto_shash_alg(hash);
int err;
crypto: hash - prevent using keyed hashes without setting key Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot <syzkaller@googlegroups.com> Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-03 22:16:27 +03:00
hash->descsize = alg->descsize;
shash_set_needkey(hash, alg);
if (alg->exit_tfm)
tfm->exit = crypto_shash_exit_tfm;
if (!alg->init_tfm)
return 0;
err = alg->init_tfm(hash);
if (err)
return err;
/* ->init_tfm() may have increased the descsize. */
if (WARN_ON_ONCE(hash->descsize > HASH_MAX_DESCSIZE)) {
if (alg->exit_tfm)
alg->exit_tfm(hash);
return -EINVAL;
}
return 0;
}
static void crypto_shash_free_instance(struct crypto_instance *inst)
{
struct shash_instance *shash = shash_instance(inst);
shash->free(shash);
}
static int __maybe_unused crypto_shash_report(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_hash rhash;
struct shash_alg *salg = __crypto_shash_alg(alg);
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 4473710df1f8 ("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 cac5818c25d0 ("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>
2018-11-04 00:56:03 +03:00
memset(&rhash, 0, sizeof(rhash));
strscpy(rhash.type, "shash", sizeof(rhash.type));
rhash.blocksize = alg->cra_blocksize;
rhash.digestsize = salg->digestsize;
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 4473710df1f8 ("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 cac5818c25d0 ("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>
2018-11-04 00:56:03 +03:00
return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
}
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
{
struct shash_alg *salg = __crypto_shash_alg(alg);
seq_printf(m, "type : shash\n");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "digestsize : %u\n", salg->digestsize);
}
static int __maybe_unused crypto_shash_report_stat(
struct sk_buff *skb, struct crypto_alg *alg)
{
return crypto_hash_report_stat(skb, alg, "shash");
}
static const struct crypto_type crypto_shash_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_shash_init_tfm,
.free = crypto_shash_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_shash_show,
#endif
#ifdef CONFIG_CRYPTO_USER
.report = crypto_shash_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
.report_stat = crypto_shash_report_stat,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_SHASH,
.tfmsize = offsetof(struct crypto_shash, base),
};
int crypto_grab_shash(struct crypto_shash_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_shash_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_shash);
struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_shash);
int crypto_has_shash(const char *alg_name, u32 type, u32 mask)
{
return crypto_type_has_alg(alg_name, &crypto_shash_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_has_shash);
int hash_prepare_alg(struct hash_alg_common *alg)
{
struct crypto_istat_hash *istat = hash_get_stat(alg);
struct crypto_alg *base = &alg->base;
if (alg->digestsize > HASH_MAX_DIGESTSIZE)
return -EINVAL;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
memset(istat, 0, sizeof(*istat));
return 0;
}
static int shash_prepare_alg(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
int err;
if (alg->descsize > HASH_MAX_DESCSIZE)
return -EINVAL;
if (base->cra_alignmask > MAX_SHASH_ALIGNMASK)
return -EINVAL;
if ((alg->export && !alg->import) || (alg->import && !alg->export))
return -EINVAL;
err = hash_prepare_alg(&alg->halg);
if (err)
return err;
base->cra_type = &crypto_shash_type;
base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
if (!alg->finup)
alg->finup = shash_finup_unaligned;
if (!alg->digest)
alg->digest = shash_digest_unaligned;
if (!alg->export) {
alg->export = shash_default_export;
alg->import = shash_default_import;
alg->halg.statesize = alg->descsize;
}
if (!alg->setkey)
alg->setkey = shash_no_setkey;
return 0;
}
int crypto_register_shash(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->base;
int err;
err = shash_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_shash);
void crypto_unregister_shash(struct shash_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shash);
int crypto_register_shashes(struct shash_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_shash(&algs[i]);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_shash(&algs[i]);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_shashes);
void crypto_unregister_shashes(struct shash_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_shash(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_shashes);
int shash_register_instance(struct crypto_template *tmpl,
struct shash_instance *inst)
{
int err;
if (WARN_ON(!inst->free))
return -EINVAL;
err = shash_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, shash_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(shash_register_instance);
void shash_free_singlespawn_instance(struct shash_instance *inst)
{
crypto_drop_spawn(shash_instance_ctx(inst));
kfree(inst);
}
EXPORT_SYMBOL_GPL(shash_free_singlespawn_instance);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synchronous cryptographic hash type");