From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Date: Tue, 24 Jul 2018 16:49:28 +0000 Subject: [PATCH v6 10/18] x86/power/64: Remove VLA usage Message-Id: <20180724164936.37477-11-keescook@chromium.org> List-Id: References: <20180724164936.37477-1-keescook@chromium.org> In-Reply-To: <20180724164936.37477-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Herbert Xu Cc: Kees Cook , Arnd Bergmann , Eric Biggers , "Gustavo A. R. Silva" , Alasdair Kergon , Rabin Vincent , Tim Chen , "Rafael J. Wysocki" , Pavel Machek , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Philipp Reisner , Lars Ellenberg , Jens Axboe , Giovanni Cabiddu , Mike Snitzer , Paul Mackerras , Greg Kroah-Hartman , David Howells , Johannes Berg , Tudor-Dan Ambarus , Jia-Ju Bai , Andrew Morton , Geert Uytterhoeven , Josh Poimboeuf , David Woodhouse , Will Deacon , dm-devel@redhat.com, linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, qat-linux@intel.com, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-afs@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org 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 Acked-by: Pavel Machek --- arch/x86/power/hibernate_64.c | 36 ++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c index 67ccf64c8bd8..f8e3b668d20b 100644 --- a/arch/x86/power/hibernate_64.c +++ b/arch/x86/power/hibernate_64.c @@ -233,29 +233,35 @@ 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); + desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), + GFP_KERNEL); + if (!desc) { + ret = -ENOMEM; + goto free_tfm; } - crypto_free_ahash(tfm); + 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); + +free_tfm: + crypto_free_shash(tfm); return ret; } -- 2.17.1