From: Kees Cook <keescook@chromium.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Arnd Bergmann <arnd@arndb.de>, Eric Biggers <ebiggers@google.com>,
Alasdair Kergon <agk@redhat.com>,
Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
Lars Persson <larper@axis.com>, Mike Snitzer <snitzer@redhat.com>,
Rabin Vincent <rabinv@axis.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
"David S. Miller" <davem@davemloft.net>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-crypto@vger.kernel.org, qat-linux@intel.com,
dm-devel@redhat.com, linux-kernel@vger.kernel.org
Subject: [PATCH v4 03/14] crypto: shash: Remove VLA usage
Date: Wed, 11 Jul 2018 13:36:08 -0700 [thread overview]
Message-ID: <20180711203619.1020-4-keescook@chromium.org> (raw)
In-Reply-To: <20180711203619.1020-1-keescook@chromium.org>
In the quest to remove all stack VLA usage from the kernel[1], this
removes the VLAs in SHASH_DESC_ON_STACK (via crypto_shash_descsize())
by using the maximum allowable size (which is now more clearly captured
in a macro). Similar limits are turned into macros as well.
A review of existing sizes shows that SHA512_DIGEST_SIZE (64) is the
largest digest size and that sizeof(struct sha3_state) (360) is the
largest descriptor size. The corresponding maximums are reduced.
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
crypto/shash.c | 6 +++---
include/crypto/hash.h | 6 +++++-
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/crypto/shash.c b/crypto/shash.c
index 5d732c6bb4b2..ab6902c6dae7 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -458,9 +458,9 @@ static int shash_prepare_alg(struct shash_alg *alg)
{
struct crypto_alg *base = &alg->base;
- if (alg->digestsize > PAGE_SIZE / 8 ||
- alg->descsize > PAGE_SIZE / 8 ||
- alg->statesize > PAGE_SIZE / 8)
+ if (alg->digestsize > SHASH_MAX_DIGESTSIZE ||
+ alg->descsize > SHASH_MAX_DESCSIZE ||
+ alg->statesize > SHASH_MAX_STATESIZE)
return -EINVAL;
base->cra_type = &crypto_shash_type;
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 76e432cab75d..ae14cc0e0cdb 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -151,9 +151,13 @@ struct shash_desc {
void *__ctx[] CRYPTO_MINALIGN_ATTR;
};
+#define SHASH_MAX_DIGESTSIZE 64
+#define SHASH_MAX_DESCSIZE 360
+#define SHASH_MAX_STATESIZE 512
+
#define SHASH_DESC_ON_STACK(shash, ctx) \
char __##shash##_desc[sizeof(struct shash_desc) + \
- crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
+ SHASH_MAX_DESCSIZE] CRYPTO_MINALIGN_ATTR; \
struct shash_desc *shash = (struct shash_desc *)__##shash##_desc
/**
--
2.17.1
next prev parent reply other threads:[~2018-07-11 20:36 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-11 20:36 [PATCH v4 00/14] crypto: Remove VLA usage Kees Cook
2018-07-11 20:36 ` [PATCH v4 01/14] crypto: xcbc: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 02/14] crypto: cbc: " Kees Cook
2018-07-11 20:36 ` Kees Cook [this message]
2018-07-11 20:36 ` [PATCH v4 04/14] dm integrity: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 05/14] crypto: ahash: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 06/14] dm verity fec: " Kees Cook
2018-07-11 20:36 ` [PATCH v4 07/14] crypto alg: Introduce generic max blocksize and alignmask Kees Cook
2018-07-11 20:36 ` [PATCH v4 08/14] crypto: qat: Remove VLA usage Kees Cook
2018-07-11 20:36 ` [PATCH v4 09/14] crypto: shash: Remove VLA usage in unaligned hashing Kees Cook
2018-07-11 20:36 ` [PATCH v4 10/14] kbuild: Introduce FRAME_WARN_BUMP_FLAG Kees Cook
2018-07-11 20:36 ` [PATCH v4 11/14] treewide: Prepare to remove VLA usage for AHASH_REQUEST_ON_STACK Kees Cook
2018-07-12 16:02 ` Arnd Bergmann
2018-07-12 20:17 ` Kees Cook
2018-07-12 21:38 ` Arnd Bergmann
2018-07-13 0:40 ` Herbert Xu
2018-07-13 3:33 ` Kees Cook
2018-07-13 3:44 ` Herbert Xu
2018-07-13 5:17 ` Kees Cook
2018-07-13 5:20 ` Herbert Xu
2018-07-13 6:00 ` Kees Cook
2018-07-13 10:14 ` Arnd Bergmann
2018-07-15 4:28 ` Kees Cook
2018-07-17 20:59 ` Arnd Bergmann
2018-07-18 14:50 ` Ard Biesheuvel
2018-07-18 15:19 ` Ard Biesheuvel
2018-07-18 15:33 ` Arnd Bergmann
2018-07-18 15:33 ` Ard Biesheuvel
2018-07-19 2:51 ` Kees Cook
2018-07-19 2:55 ` Ard Biesheuvel
2018-07-19 3:09 ` Kees Cook
2018-07-19 3:13 ` Ard Biesheuvel
2018-07-19 14:54 ` Ard Biesheuvel
2018-07-19 18:44 ` Kees Cook
2018-07-13 6:16 ` Kees Cook
2018-07-13 6:22 ` Herbert Xu
2018-07-14 3:07 ` Kees Cook
2018-07-15 2:44 ` Herbert Xu
2018-07-15 2:59 ` Kees Cook
2018-07-16 0:01 ` Herbert Xu
2018-07-16 3:39 ` Kees Cook
2018-07-16 7:24 ` Arnd Bergmann
2018-07-11 20:36 ` [PATCH v4 12/14] crypto: ahash: Remove " Kees Cook
2018-07-11 20:36 ` [PATCH v4 13/14] rxrpc: Prepare to remove VLA usage for SKCIPHER_REQUEST_ON_STACK Kees Cook
2018-07-12 15:11 ` Arnd Bergmann
2018-07-12 20:23 ` Kees Cook
2018-07-12 20:30 ` Kees Cook
2018-07-12 21:15 ` Arnd Bergmann
2018-07-12 21:38 ` Kees Cook
2018-07-12 21:28 ` David Howells
2018-07-12 21:34 ` Kees Cook
2018-07-12 22:05 ` David Howells
2018-07-11 20:36 ` [PATCH v4 14/14] crypto: skcipher: Remove " Kees Cook
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