From: Kees Cook <keescook@chromium.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
Matthew Wilcox <willy@infradead.org>,
linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
Mike Snitzer <snitzer@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Eric Biggers <ebiggers@google.com>,
Will Deacon <will.deacon@arm.com>,
qat-linux@intel.com, Arnd Bergmann <arnd@arndb.de>,
"David S. Miller" <davem@davemloft.net>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
dm-devel@redhat.com, Geert Uytterhoeven <geert@linux-m68k.org>,
David Woodhouse <dwmw@amazon.co.uk>,
Tudor-Dan Ambarus <tudor.ambarus@microchip.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alasdair Kergon <agk@redhat.com>,
linux-crypto@vger.kernel.org
Subject: [PATCH v8 4/9] crypto: hash: Remove VLA usage
Date: Tue, 7 Aug 2018 14:18:38 -0700 [thread overview]
Message-ID: <20180807211843.47586-5-keescook@chromium.org> (raw)
In-Reply-To: <20180807211843.47586-1-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), along with a few other cases. 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/ahash.c | 4 ++--
crypto/algif_hash.c | 2 +-
crypto/shash.c | 6 +++---
include/crypto/hash.h | 6 +++++-
4 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/crypto/ahash.c b/crypto/ahash.c
index a64c143165b1..78aaf2158c43 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -550,8 +550,8 @@ static int ahash_prepare_alg(struct ahash_alg *alg)
{
struct crypto_alg *base = &alg->halg.base;
- if (alg->halg.digestsize > PAGE_SIZE / 8 ||
- alg->halg.statesize > PAGE_SIZE / 8 ||
+ if (alg->halg.digestsize > HASH_MAX_DIGESTSIZE ||
+ alg->halg.statesize > HASH_MAX_STATESIZE ||
alg->halg.statesize == 0)
return -EINVAL;
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index bfcf595fd8f9..d0cde541beb6 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -239,7 +239,7 @@ static int hash_accept(struct socket *sock, struct socket *newsock, int flags,
struct alg_sock *ask = alg_sk(sk);
struct hash_ctx *ctx = ask->private;
struct ahash_request *req = &ctx->req;
- char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1];
+ char state[HASH_MAX_STATESIZE];
struct sock *sk2;
struct alg_sock *ask2;
struct hash_ctx *ctx2;
diff --git a/crypto/shash.c b/crypto/shash.c
index 5d732c6bb4b2..86d76b5c626c 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 > HASH_MAX_DIGESTSIZE ||
+ alg->descsize > HASH_MAX_DESCSIZE ||
+ alg->statesize > HASH_MAX_STATESIZE)
return -EINVAL;
base->cra_type = &crypto_shash_type;
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 76e432cab75d..21587011ab0f 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -151,9 +151,13 @@ struct shash_desc {
void *__ctx[] CRYPTO_MINALIGN_ATTR;
};
+#define HASH_MAX_DIGESTSIZE 64
+#define HASH_MAX_DESCSIZE 360
+#define HASH_MAX_STATESIZE 512
+
#define SHASH_DESC_ON_STACK(shash, ctx) \
char __##shash##_desc[sizeof(struct shash_desc) + \
- crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
+ HASH_MAX_DESCSIZE] CRYPTO_MINALIGN_ATTR; \
struct shash_desc *shash = (struct shash_desc *)__##shash##_desc
/**
--
2.17.1
next prev parent reply other threads:[~2018-08-07 21:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 21:18 [PATCH v8 0/9] crypto: Remove VLA usage Kees Cook
2018-08-07 21:18 ` [PATCH v8 1/9] crypto: xcbc: " Kees Cook
2018-08-07 21:18 ` [PATCH v8 2/9] crypto: cbc: " Kees Cook
2018-08-07 21:18 ` [PATCH v8 3/9] crypto: ccm: " Kees Cook
2018-08-07 21:18 ` Kees Cook [this message]
2018-08-07 21:18 ` [PATCH v8 5/9] dm: Remove VLA usage from hashes Kees Cook
2018-09-04 3:13 ` Herbert Xu
2018-09-13 16:41 ` Kees Cook
2018-09-13 17:54 ` Mike Snitzer
2018-09-14 6:10 ` Herbert Xu
2018-08-07 21:18 ` [PATCH v8 6/9] crypto alg: Introduce generic max blocksize and alignmask Kees Cook
2018-08-07 21:18 ` [PATCH v8 7/9] crypto: qat: Remove VLA usage Kees Cook
2018-09-25 16:12 ` Arnd Bergmann
2018-09-26 8:44 ` Ard Biesheuvel
2018-09-26 8:53 ` Arnd Bergmann
2018-09-26 8:55 ` Ard Biesheuvel
2018-08-07 21:18 ` [PATCH v8 8/9] crypto: shash: Remove VLA usage in unaligned hashing Kees Cook
2018-08-07 21:18 ` [PATCH v8 9/9] crypto: skcipher: Remove VLA usage for SKCIPHER_REQUEST_ON_STACK Kees Cook
2018-09-04 3:15 ` Herbert Xu
2018-09-04 5:19 ` [PATCH v8 0/9] crypto: Remove VLA usage Herbert Xu
2018-09-04 5:50 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180807211843.47586-5-keescook@chromium.org \
--to=keescook@chromium.org \
--cc=agk@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=ard.biesheuvel@linaro.org \
--cc=arnd@arndb.de \
--cc=davem@davemloft.net \
--cc=dm-devel@redhat.com \
--cc=dwmw@amazon.co.uk \
--cc=ebiggers@google.com \
--cc=geert@linux-m68k.org \
--cc=giovanni.cabiddu@intel.com \
--cc=gustavo@embeddedor.com \
--cc=herbert@gondor.apana.org.au \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=qat-linux@intel.com \
--cc=snitzer@redhat.com \
--cc=tglx@linutronix.de \
--cc=tudor.ambarus@microchip.com \
--cc=will.deacon@arm.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).