From: Kees Cook <keescook@chromium.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>,
Herbert Xu <herbert@gondor.apana.org.au>,
Arnd Bergmann <arnd@arndb.de>, Eric Biggers <ebiggers@google.com>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] x86/power/64: Remove VLA usage
Date: Sun, 15 Jul 2018 20:56:57 -0700 [thread overview]
Message-ID: <20180716035657.GA32180@beast> (raw)
In the quest to remove all stack VLA usage from the kernel[1], this
removes the discouraged use of AHASH_REQUEST_ON_STACK by switching to
shash directly and allocating the descriptor in heap memory (which should
be fine: the tfm has already been allocated there too).
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/power/hibernate_64.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index 67ccf64c8bd8..0ed01bb935a6 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -233,28 +233,31 @@ struct restore_data_record {
*/
static int get_e820_md5(struct e820_table *table, void *buf)
{
- struct scatterlist sg;
- struct crypto_ahash *tfm;
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
int size;
int ret = 0;
- tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
+ tfm = crypto_alloc_shash("md5", 0, 0);
if (IS_ERR(tfm))
return -ENOMEM;
- {
- AHASH_REQUEST_ON_STACK(req, tfm);
- size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
- ahash_request_set_tfm(req, tfm);
- sg_init_one(&sg, (u8 *)table, size);
- ahash_request_set_callback(req, 0, NULL, NULL);
- ahash_request_set_crypt(req, &sg, buf, size);
-
- if (crypto_ahash_digest(req))
- ret = -EINVAL;
- ahash_request_zero(req);
- }
- crypto_free_ahash(tfm);
+ desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
+ GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+
+ desc->tfm = tfm;
+ desc->flags = 0;
+
+ size = offsetof(struct e820_table, entries) +
+ sizeof(struct e820_entry) * table->nr_entries;
+
+ if (crypto_shash_digest(desc, (u8 *)table, size, buf))
+ ret = -EINVAL;
+
+ kzfree(desc);
+ crypto_free_shash(tfm);
return ret;
}
--
2.17.1
--
Kees Cook
Pixel Security
next reply other threads:[~2018-07-16 3:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 3:56 Kees Cook [this message]
2018-07-16 8:52 ` [PATCH] x86/power/64: Remove VLA usage Pavel Machek
2018-07-16 17:22 ` Eric Biggers
2018-07-19 4:39 ` Kees Cook
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