From: Kees Cook <keescook@chromium.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>,
Eric Biggers <ebiggers@google.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Gilad Ben-Yossef <gilad@benyossef.com>,
Alexander Stein <alexander.stein@systec-electronic.com>,
Antoine Tenart <antoine.tenart@bootlin.com>,
Boris Brezillon <boris.brezillon@bootlin.com>,
Arnaud Ebalard <arno@natisbad.org>,
Corentin Labbe <clabbe.montjoie@gmail.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Chen-Yu Tsai <wens@csie.org>,
Christian Lamparter <chunkeey@gmail.com>,
Philippe Ombredanne <pombredanne@nexb.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/4] crypto: skcipher - Enforce non-ASYNC for on-stack requests
Date: Thu, 6 Sep 2018 15:58:52 -0700 [thread overview]
Message-ID: <20180906225854.40989-3-keescook@chromium.org> (raw)
In-Reply-To: <20180906225854.40989-1-keescook@chromium.org>
Check at use-time whether an skcipher request is on the stack. If it
is, enforce that it must be backed by a synchronous algorithm, as is
required:
https://www.redhat.com/archives/dm-devel/2018-January/msg00087.html
Co-developed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/crypto/skcipher.h | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h
index 6e954d398e0f..3aabd5d098ed 100644
--- a/include/crypto/skcipher.h
+++ b/include/crypto/skcipher.h
@@ -19,6 +19,7 @@
/**
* struct skcipher_request - Symmetric key cipher request
+ * @__onstack: 1 if the request was allocated by SKCIPHER_REQUEST_ON_STACK
* @cryptlen: Number of bytes to encrypt or decrypt
* @iv: Initialisation Vector
* @src: Source SG list
@@ -27,6 +28,7 @@
* @__ctx: Start of private context data
*/
struct skcipher_request {
+ unsigned char __onstack;
unsigned int cryptlen;
u8 *iv;
@@ -139,9 +141,12 @@ struct skcipher_alg {
struct crypto_alg base;
};
+/*
+ * This must only ever be used with synchronous algorithms.
+ */
#define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
char __##name##_desc[sizeof(struct skcipher_request) + \
- crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
+ crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR = { 1 }; \
struct skcipher_request *name = (void *)__##name##_desc
/**
@@ -437,6 +442,12 @@ static inline struct crypto_skcipher *crypto_skcipher_reqtfm_check(
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ if (req->__onstack) {
+ if (WARN_ON(crypto_skcipher_alg(tfm)->base.cra_flags &
+ CRYPTO_ALG_ASYNC))
+ return ERR_PTR(-EINVAL);
+ }
+
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return ERR_PTR(-ENOKEY);
--
2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: keescook@chromium.org (Kees Cook)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/4] crypto: skcipher - Enforce non-ASYNC for on-stack requests
Date: Thu, 6 Sep 2018 15:58:52 -0700 [thread overview]
Message-ID: <20180906225854.40989-3-keescook@chromium.org> (raw)
In-Reply-To: <20180906225854.40989-1-keescook@chromium.org>
Check at use-time whether an skcipher request is on the stack. If it
is, enforce that it must be backed by a synchronous algorithm, as is
required:
https://www.redhat.com/archives/dm-devel/2018-January/msg00087.html
Co-developed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/crypto/skcipher.h | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h
index 6e954d398e0f..3aabd5d098ed 100644
--- a/include/crypto/skcipher.h
+++ b/include/crypto/skcipher.h
@@ -19,6 +19,7 @@
/**
* struct skcipher_request - Symmetric key cipher request
+ * @__onstack: 1 if the request was allocated by SKCIPHER_REQUEST_ON_STACK
* @cryptlen: Number of bytes to encrypt or decrypt
* @iv: Initialisation Vector
* @src: Source SG list
@@ -27,6 +28,7 @@
* @__ctx: Start of private context data
*/
struct skcipher_request {
+ unsigned char __onstack;
unsigned int cryptlen;
u8 *iv;
@@ -139,9 +141,12 @@ struct skcipher_alg {
struct crypto_alg base;
};
+/*
+ * This must only ever be used with synchronous algorithms.
+ */
#define SKCIPHER_REQUEST_ON_STACK(name, tfm) \
char __##name##_desc[sizeof(struct skcipher_request) + \
- crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR; \
+ crypto_skcipher_reqsize(tfm)] CRYPTO_MINALIGN_ATTR = { 1 }; \
struct skcipher_request *name = (void *)__##name##_desc
/**
@@ -437,6 +442,12 @@ static inline struct crypto_skcipher *crypto_skcipher_reqtfm_check(
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ if (req->__onstack) {
+ if (WARN_ON(crypto_skcipher_alg(tfm)->base.cra_flags &
+ CRYPTO_ALG_ASYNC))
+ return ERR_PTR(-EINVAL);
+ }
+
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return ERR_PTR(-ENOKEY);
--
2.17.1
next prev parent reply other threads:[~2018-09-06 22:58 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 22:58 [PATCH v2 0/4] crypto: skcipher - Remove VLA usage Kees Cook
2018-09-06 22:58 ` Kees Cook
2018-09-06 22:58 ` [PATCH v2 1/4] crypto: skcipher - Consolidate encrypt/decrypt sanity check Kees Cook
2018-09-06 22:58 ` Kees Cook
2018-09-06 22:58 ` Kees Cook [this message]
2018-09-06 22:58 ` [PATCH v2 2/4] crypto: skcipher - Enforce non-ASYNC for on-stack requests Kees Cook
2018-09-07 3:42 ` Herbert Xu
2018-09-07 3:42 ` Herbert Xu
2018-09-07 6:56 ` Ard Biesheuvel
2018-09-07 6:56 ` Ard Biesheuvel
2018-09-07 6:56 ` Ard Biesheuvel
2018-09-11 5:52 ` Herbert Xu
2018-09-11 5:52 ` Herbert Xu
2018-09-11 5:52 ` Herbert Xu
2018-09-13 16:46 ` Kees Cook
2018-09-13 16:46 ` Kees Cook
2018-09-13 16:46 ` Kees Cook
2018-09-13 17:40 ` Kees Cook
2018-09-13 17:40 ` Kees Cook
2018-09-13 17:40 ` Kees Cook
2018-09-07 16:02 ` Kees Cook
2018-09-07 16:02 ` Kees Cook
2018-09-11 5:53 ` Herbert Xu
2018-09-11 5:53 ` Herbert Xu
2018-09-06 22:58 ` [PATCH v2 3/4] crypto: skcipher - Remove VLA usage for SKCIPHER_REQUEST_ON_STACK Kees Cook
2018-09-06 22:58 ` Kees Cook
2018-09-06 22:58 ` [PATCH 4/4] crypto: skcipher - Remove unused argument to SKCIPHER_REQUEST_ON_STACK() Kees Cook
2018-09-06 22:58 ` Kees Cook
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