From patchwork Fri Mar 22 06:29:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herbert Xu X-Patchwork-Id: 160843 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp451853jan; Thu, 21 Mar 2019 23:39:16 -0700 (PDT) X-Google-Smtp-Source: APXvYqyJyuJDFc4VyLf/Ihbt27X6GWnQdOBFrA2yYccLqVBf5vskyc9cHYHXVq8cgUSn/Ik7oW9C X-Received: by 2002:a63:6e02:: with SMTP id j2mr7035982pgc.229.1553236755974; Thu, 21 Mar 2019 23:39:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553236755; cv=none; d=google.com; s=arc-20160816; b=vYBKz1WNqPqsuaAodgVdaEVEogwamctwPzP6WNbpNrS07OuerxpmoTsW1RPUJRWhKT H0kRTvZCY145CzWgxCgdSbHqoMM8jJutqQsNcYatvGrzACY9YP1tpo7YHtoPU8is4XfF 3Xyqz9j4sSKHJZvaREydv3Udjc+zRGLmbb4Fel1PRUsRwzXtXt+NSJKdAtLC0SN6oi3n jKgOGrOnERgp2t97JmgKpN7lNxz2OE0v0FxieOt+Yr2Q7QLn/SCxvKgxyPz5HyE3vSwY /OqpAqwgN45kM4F0KFTZlpnHJjlRUo9iO5IIHxdHipoGy1h8y4UnlaTCQIEWObKaCkqA DZFQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:date:from:message-id:to:references :subject; bh=EeTX8ff8xhYtSMVmpPGJ+0VG0OdW7Gic80dH4K9z6XE=; b=bMahO+ZpAUJ+en/IvkoJ875BLpWhz9oUOw/ziUjLzhv43num+WlPIkSewy8dZ2wQnn qfcxNuGo7kVy5LItL8PmZit/wmy9M8Dg+CvIwH9k19wB2q+fD1wiqBSkXFM2qecrCBaS LDeEhrb6ovgy7nbbrAb00iaQzxWaImTxf6pzhxw7jnd8iHisRwEgEtllC0RTq/ssPHD2 AXZ41c9hXX0EsIPhIxrNCoXg0HoG2cXhqzRPTH0OCbxHlW1ONiLbFmbws5Lv0Hfyn5Gd dAm/DM7UpIdhAw+kh6LYkX0UO/gFvAhTy0J82vTLZUfjoC/W4mFNPPN2wT6Jv0zw3tUW VUyw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-crypto-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-crypto-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b4si6164618pfj.16.2019.03.21.23.39.15; Thu, 21 Mar 2019 23:39:15 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-crypto-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-crypto-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-crypto-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727745AbfCVGjP (ORCPT + 3 others); Fri, 22 Mar 2019 02:39:15 -0400 Received: from orcrist.hmeau.com ([104.223.48.154]:44304 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727461AbfCVGjP (ORCPT ); Fri, 22 Mar 2019 02:39:15 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1h7Dh3-0002ZM-Aw; Fri, 22 Mar 2019 14:30:20 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1h7Dgk-0001K4-Mg; Fri, 22 Mar 2019 14:29:59 +0800 Subject: [PATCH 17/17] security/keys: rewrite big_key crypto to use Zinc References: <20190322062740.nrwfx2rvmt7lzotj@gondor.apana.org.au> To: Linus Torvalds , "David S. Miller" , "Jason A. Donenfeld" , Eric Biggers , Ard Biesheuvel , Linux Crypto Mailing List , linux-fscrypt@vger.kernel.org, linux-arm-kernel@lists.infradead.org, LKML , Paul Crowley , Greg Kaiser , Samuel Neves , Tomer Ashur , Martin Willi Message-Id: From: Herbert Xu Date: Fri, 22 Mar 2019 14:29:58 +0800 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org From: Jason A. Donenfeld A while back, I noticed that the crypto and crypto API usage in big_keys were entirely broken in multiple ways, so I rewrote it. Now, I'm rewriting it again, but this time using Zinc's ChaCha20Poly1305 function. This makes the file considerably more simple; the diffstat alone should justify this commit. It also should be faster, since it no longer requires a mutex around the "aead api object" (nor allocations), allowing us to encrypt multiple items in parallel. We also benefit from being able to pass any type of pointer to Zinc, so we can get rid of the ridiculously complex custom page allocator that big_key really doesn't need. Signed-off-by: Jason A. Donenfeld Cc: David Howells Cc: Samuel Neves Cc: Jean-Philippe Aumasson Cc: Andy Lutomirski Cc: Greg KH Cc: Andrew Morton Cc: Linus Torvalds Cc: kernel-hardening@lists.openwall.com Signed-off-by: Herbert Xu --- security/keys/Kconfig | 4 security/keys/big_key.c | 230 +++++------------------------------------------- 2 files changed, 28 insertions(+), 206 deletions(-) diff --git a/security/keys/Kconfig b/security/keys/Kconfig index 6462e6654ccf..66ff26298fb3 100644 --- a/security/keys/Kconfig +++ b/security/keys/Kconfig @@ -45,9 +45,7 @@ config BIG_KEYS bool "Large payload keys" depends on KEYS depends on TMPFS - select CRYPTO - select CRYPTO_AES - select CRYPTO_GCM + select ZINC_CHACHA20POLY1305 help This option provides support for holding large keys within the kernel (for example Kerberos ticket caches). The data may be stored out to diff --git a/security/keys/big_key.c b/security/keys/big_key.c index 2806e70d7f8f..bb15360221d8 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -1,6 +1,6 @@ /* Large capacity key type * - * Copyright (C) 2017 Jason A. Donenfeld . All Rights Reserved. + * Copyright (C) 2017-2018 Jason A. Donenfeld . All Rights Reserved. * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * @@ -16,20 +16,10 @@ #include #include #include -#include #include -#include #include #include -#include -#include - -struct big_key_buf { - unsigned int nr_pages; - void *virt; - struct scatterlist *sg; - struct page *pages[]; -}; +#include /* * Layout of key payload words. @@ -42,14 +32,6 @@ enum { }; /* - * Crypto operation with big_key data - */ -enum big_key_op { - BIG_KEY_ENC, - BIG_KEY_DEC, -}; - -/* * If the data is under this limit, there's no point creating a shm file to * hold it as the permanently resident metadata for the shmem fs will be at * least as large as the data. @@ -57,16 +39,6 @@ enum big_key_op { #define BIG_KEY_FILE_THRESHOLD (sizeof(struct inode) + sizeof(struct dentry)) /* - * Key size for big_key data encryption - */ -#define ENC_KEY_SIZE 32 - -/* - * Authentication tag length - */ -#define ENC_AUTHTAG_SIZE 16 - -/* * big_key defined keys take an arbitrary string as the description and an * arbitrary blob of data as the payload */ @@ -79,136 +51,20 @@ struct key_type key_type_big_key = { .destroy = big_key_destroy, .describe = big_key_describe, .read = big_key_read, - /* no ->update(); don't add it without changing big_key_crypt() nonce */ + /* no ->update(); don't add it without changing chacha20poly1305's nonce */ }; /* - * Crypto names for big_key data authenticated encryption - */ -static const char big_key_alg_name[] = "gcm(aes)"; -#define BIG_KEY_IV_SIZE GCM_AES_IV_SIZE - -/* - * Crypto algorithms for big_key data authenticated encryption - */ -static struct crypto_aead *big_key_aead; - -/* - * Since changing the key affects the entire object, we need a mutex. - */ -static DEFINE_MUTEX(big_key_aead_lock); - -/* - * Encrypt/decrypt big_key data - */ -static int big_key_crypt(enum big_key_op op, struct big_key_buf *buf, size_t datalen, u8 *key) -{ - int ret; - struct aead_request *aead_req; - /* We always use a zero nonce. The reason we can get away with this is - * because we're using a different randomly generated key for every - * different encryption. Notably, too, key_type_big_key doesn't define - * an .update function, so there's no chance we'll wind up reusing the - * key to encrypt updated data. Simply put: one key, one encryption. - */ - u8 zero_nonce[BIG_KEY_IV_SIZE]; - - aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL); - if (!aead_req) - return -ENOMEM; - - memset(zero_nonce, 0, sizeof(zero_nonce)); - aead_request_set_crypt(aead_req, buf->sg, buf->sg, datalen, zero_nonce); - aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); - aead_request_set_ad(aead_req, 0); - - mutex_lock(&big_key_aead_lock); - if (crypto_aead_setkey(big_key_aead, key, ENC_KEY_SIZE)) { - ret = -EAGAIN; - goto error; - } - if (op == BIG_KEY_ENC) - ret = crypto_aead_encrypt(aead_req); - else - ret = crypto_aead_decrypt(aead_req); -error: - mutex_unlock(&big_key_aead_lock); - aead_request_free(aead_req); - return ret; -} - -/* - * Free up the buffer. - */ -static void big_key_free_buffer(struct big_key_buf *buf) -{ - unsigned int i; - - if (buf->virt) { - memset(buf->virt, 0, buf->nr_pages * PAGE_SIZE); - vunmap(buf->virt); - } - - for (i = 0; i < buf->nr_pages; i++) - if (buf->pages[i]) - __free_page(buf->pages[i]); - - kfree(buf); -} - -/* - * Allocate a buffer consisting of a set of pages with a virtual mapping - * applied over them. - */ -static void *big_key_alloc_buffer(size_t len) -{ - struct big_key_buf *buf; - unsigned int npg = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; - unsigned int i, l; - - buf = kzalloc(sizeof(struct big_key_buf) + - sizeof(struct page) * npg + - sizeof(struct scatterlist) * npg, - GFP_KERNEL); - if (!buf) - return NULL; - - buf->nr_pages = npg; - buf->sg = (void *)(buf->pages + npg); - sg_init_table(buf->sg, npg); - - for (i = 0; i < buf->nr_pages; i++) { - buf->pages[i] = alloc_page(GFP_KERNEL); - if (!buf->pages[i]) - goto nomem; - - l = min_t(size_t, len, PAGE_SIZE); - sg_set_page(&buf->sg[i], buf->pages[i], l, 0); - len -= l; - } - - buf->virt = vmap(buf->pages, buf->nr_pages, VM_MAP, PAGE_KERNEL); - if (!buf->virt) - goto nomem; - - return buf; - -nomem: - big_key_free_buffer(buf); - return NULL; -} - -/* * Preparse a big key */ int big_key_preparse(struct key_preparsed_payload *prep) { - struct big_key_buf *buf; struct path *path = (struct path *)&prep->payload.data[big_key_path]; struct file *file; - u8 *enckey; + u8 *buf, *enckey; ssize_t written; - size_t datalen = prep->datalen, enclen = datalen + ENC_AUTHTAG_SIZE; + size_t datalen = prep->datalen; + size_t enclen = datalen + CHACHA20POLY1305_AUTHTAG_SIZE; int ret; if (datalen <= 0 || datalen > 1024 * 1024 || !prep->data) @@ -224,28 +80,28 @@ int big_key_preparse(struct key_preparsed_payload *prep) * to be swapped out if needed. * * File content is stored encrypted with randomly generated key. + * Since the key is random for each file, we can set the nonce + * to zero, provided we never define a ->update() call. */ loff_t pos = 0; - buf = big_key_alloc_buffer(enclen); + buf = kvmalloc(enclen, GFP_KERNEL); if (!buf) return -ENOMEM; - memcpy(buf->virt, prep->data, datalen); /* generate random key */ - enckey = kmalloc(ENC_KEY_SIZE, GFP_KERNEL); + enckey = kmalloc(CHACHA20POLY1305_KEY_SIZE, GFP_KERNEL); if (!enckey) { ret = -ENOMEM; goto error; } - ret = get_random_bytes_wait(enckey, ENC_KEY_SIZE); + ret = get_random_bytes_wait(enckey, CHACHA20POLY1305_KEY_SIZE); if (unlikely(ret)) goto err_enckey; - /* encrypt aligned data */ - ret = big_key_crypt(BIG_KEY_ENC, buf, datalen, enckey); - if (ret) - goto err_enckey; + /* encrypt data */ + chacha20poly1305_encrypt(buf, prep->data, datalen, NULL, 0, + 0, enckey); /* save aligned data to file */ file = shmem_kernel_file_setup("", enclen, 0); @@ -254,7 +110,7 @@ int big_key_preparse(struct key_preparsed_payload *prep) goto err_enckey; } - written = kernel_write(file, buf->virt, enclen, &pos); + written = kernel_write(file, buf, enclen, &pos); if (written != enclen) { ret = written; if (written >= 0) @@ -269,7 +125,7 @@ int big_key_preparse(struct key_preparsed_payload *prep) *path = file->f_path; path_get(path); fput(file); - big_key_free_buffer(buf); + kvfree(buf); } else { /* Just store the data in a buffer */ void *data = kmalloc(datalen, GFP_KERNEL); @@ -287,7 +143,7 @@ int big_key_preparse(struct key_preparsed_payload *prep) err_enckey: kzfree(enckey); error: - big_key_free_buffer(buf); + kvfree(buf); return ret; } @@ -365,14 +221,13 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen) return datalen; if (datalen > BIG_KEY_FILE_THRESHOLD) { - struct big_key_buf *buf; struct path *path = (struct path *)&key->payload.data[big_key_path]; struct file *file; - u8 *enckey = (u8 *)key->payload.data[big_key_data]; - size_t enclen = datalen + ENC_AUTHTAG_SIZE; + u8 *buf, *enckey = (u8 *)key->payload.data[big_key_data]; + size_t enclen = datalen + CHACHA20POLY1305_AUTHTAG_SIZE; loff_t pos = 0; - buf = big_key_alloc_buffer(enclen); + buf = kvmalloc(enclen, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -383,26 +238,27 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen) } /* read file to kernel and decrypt */ - ret = kernel_read(file, buf->virt, enclen, &pos); + ret = kernel_read(file, buf, enclen, &pos); if (ret >= 0 && ret != enclen) { ret = -EIO; goto err_fput; } - ret = big_key_crypt(BIG_KEY_DEC, buf, enclen, enckey); - if (ret) + ret = chacha20poly1305_decrypt(buf, buf, enclen, NULL, 0, 0, + enckey) ? 0 : -EINVAL; + if (unlikely(ret)) goto err_fput; ret = datalen; /* copy decrypted data to user */ - if (copy_to_user(buffer, buf->virt, datalen) != 0) + if (copy_to_user(buffer, buf, datalen) != 0) ret = -EFAULT; err_fput: fput(file); error: - big_key_free_buffer(buf); + kvfree(buf); } else { ret = datalen; if (copy_to_user(buffer, key->payload.data[big_key_data], @@ -418,39 +274,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen) */ static int __init big_key_init(void) { - int ret; - - /* init block cipher */ - big_key_aead = crypto_alloc_aead(big_key_alg_name, 0, CRYPTO_ALG_ASYNC); - if (IS_ERR(big_key_aead)) { - ret = PTR_ERR(big_key_aead); - pr_err("Can't alloc crypto: %d\n", ret); - return ret; - } - - if (unlikely(crypto_aead_ivsize(big_key_aead) != BIG_KEY_IV_SIZE)) { - WARN(1, "big key algorithm changed?"); - ret = -EINVAL; - goto free_aead; - } - - ret = crypto_aead_setauthsize(big_key_aead, ENC_AUTHTAG_SIZE); - if (ret < 0) { - pr_err("Can't set crypto auth tag len: %d\n", ret); - goto free_aead; - } - - ret = register_key_type(&key_type_big_key); - if (ret < 0) { - pr_err("Can't register type: %d\n", ret); - goto free_aead; - } - - return 0; - -free_aead: - crypto_free_aead(big_key_aead); - return ret; + return register_key_type(&key_type_big_key); } late_initcall(big_key_init);