From: Salvatore Mesoraca <s.mesoraca16@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: kernel-hardening@lists.openwall.com,
linux-crypto@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
Kees Cook <keescook@chromium.org>,
Salvatore Mesoraca <s.mesoraca16@gmail.com>,
Eric Biggers <ebiggers3@gmail.com>,
Laura Abbott <labbott@redhat.com>
Subject: [PATCH 3/6] crypto: api - avoid VLA use
Date: Mon, 9 Apr 2018 15:54:01 +0200 [thread overview]
Message-ID: <1523282044-22075-4-git-send-email-s.mesoraca16@gmail.com> (raw)
In-Reply-To: <1523282044-22075-1-git-send-email-s.mesoraca16@gmail.com>
We avoid a VLA[1] by always allocating MAX_BLOCKSIZE +
MAX_ALIGNMASK bytes.
We also check the selected cipher at initialization time, if
it doesn't comply with these limits, the initialization will
fail.
[1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Salvatore Mesoraca <s.mesoraca16@gmail.com>
---
crypto/cipher.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/crypto/cipher.c b/crypto/cipher.c
index 94fa355..9cedf23 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -67,7 +67,7 @@ static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
{
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
unsigned int size = crypto_tfm_alg_blocksize(tfm);
- u8 buffer[size + alignmask];
+ u8 buffer[MAX_BLOCKSIZE + MAX_ALIGNMASK];
u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
memcpy(tmp, src, size);
@@ -105,9 +105,14 @@ static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
int crypto_init_cipher_ops(struct crypto_tfm *tfm)
{
+ const unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
+ const unsigned int size = crypto_tfm_alg_blocksize(tfm);
struct cipher_tfm *ops = &tfm->crt_cipher;
struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+ if (size > MAX_BLOCKSIZE || alignmask > MAX_ALIGNMASK)
+ return -EINVAL;
+
ops->cit_setkey = setkey;
ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
cipher_encrypt_unaligned : cipher->cia_encrypt;
--
1.9.1
next prev parent reply other threads:[~2018-04-09 13:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-09 13:53 [PATCH 0/6] Remove several VLAs in the crypto subsystem Salvatore Mesoraca
2018-04-09 13:53 ` [PATCH 1/6] crypto: api - laying macros for statically allocated buffers Salvatore Mesoraca
2018-04-09 13:54 ` [PATCH 2/6] crypto: ctr - avoid VLA use Salvatore Mesoraca
2018-04-09 13:54 ` Salvatore Mesoraca [this message]
2018-04-09 13:54 ` [PATCH 4/6] crypto: pcbc " Salvatore Mesoraca
2018-04-09 13:54 ` [PATCH 5/6] crypto: cts " Salvatore Mesoraca
2018-04-09 13:54 ` [PATCH 6/6] crypto: cfb " Salvatore Mesoraca
2018-04-09 13:57 ` [PATCH 0/6] Remove several VLAs in the crypto subsystem Salvatore Mesoraca
2018-04-09 14:02 ` Salvatore Mesoraca
-- strict thread matches above, loose matches on Subject: below --
2018-04-07 18:38 Salvatore Mesoraca
2018-04-07 18:38 ` [PATCH 3/6] crypto: api - avoid VLA use Salvatore Mesoraca
2018-04-08 3:16 ` Herbert Xu
2018-04-08 9:07 ` Salvatore Mesoraca
2018-04-08 9:22 ` Herbert Xu
2018-04-09 13:27 ` Salvatore Mesoraca
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