From patchwork Mon Jun 5 03:47:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 9765399 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 3000760353 for ; Mon, 5 Jun 2017 03:49:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2053726E69 for ; Mon, 5 Jun 2017 03:49:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 151E327F9F; Mon, 5 Jun 2017 03:49:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 3F96B26E69 for ; Mon, 5 Jun 2017 03:49:09 +0000 (UTC) Received: (qmail 9240 invoked by uid 550); 5 Jun 2017 03:48:46 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 8080 invoked from network); 5 Jun 2017 03:48:45 -0000 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=from:to:cc :subject:date:message-id:in-reply-to:references; s=mail; bh=yBxz aLMhpsNF1cnuJ2o1aGuP/ao=; b=Ntx7TeKJGtdicOSnQoW/vleYaUphOXlnff5Z sj2KiJBU5t6/tMZ/Ks/VTSRmPRyadot5D4gENoTDq2lUkTveLG985uEP/tnBal2U d27U4pQqFPP0rDbZ1YnnKaI0sf7W41QAKkh8lfRpcqMcCFSZD/tszlI5Z0zBHvlN 9p0lpHXqoFDVPcCcdNVWQ0V4F05MfEAAF5GRJiFo0bGvl2JT/1H1tdV98z574iKB jiB1+Tlpcl3MHrP26lEHDxUHf2lO8Ua9amVy3ZGRImM7j06myCRYWOeLrmmMGLVZ gT7Z+T2LCoAYzDUZmE6m8g+mumB75G45uLHQvrPIqhOPJqNdtg== From: "Jason A. Donenfeld" To: Theodore Ts'o , Linux Crypto Mailing List , LKML , kernel-hardening@lists.openwall.com, Greg Kroah-Hartman Cc: "Jason A. Donenfeld" , David Howells , Mimi Zohar , David Safford Date: Mon, 5 Jun 2017 05:47:54 +0200 Message-Id: <20170605034757.4803-6-Jason@zx2c4.com> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170605034757.4803-1-Jason@zx2c4.com> References: <20170605034757.4803-1-Jason@zx2c4.com> Subject: [kernel-hardening] [PATCH RFC v2 5/8] security/keys: ensure RNG is seeded before use X-Virus-Scanned: ClamAV using ClamSMTP Otherwise, we might use bad random numbers which, particularly in the case of IV generation, could be quite bad. It makes sense to use the synchronous API here, because we're always in process context (as the code is littered with GFP_KERNEL and the like). Signed-off-by: Jason A. Donenfeld Cc: David Howells Cc: Mimi Zohar Cc: David Safford --- security/keys/encrypted-keys/encrypted.c | 8 +++++--- security/keys/key.c | 13 +++++++++---- 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 0010955d7876..d51a28fc5cd5 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -777,10 +777,12 @@ static int encrypted_init(struct encrypted_key_payload *epayload, __ekey_init(epayload, format, master_desc, datalen); if (!hex_encoded_iv) { - get_random_bytes(epayload->iv, ivsize); + ret = get_random_bytes_wait(epayload->iv, ivsize); + if (unlikely(ret)) + return ret; - get_random_bytes(epayload->decrypted_data, - epayload->decrypted_datalen); + ret = get_random_bytes_wait(epayload->decrypted_data, + epayload->decrypted_datalen); } else ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv); return ret; diff --git a/security/keys/key.c b/security/keys/key.c index 455c04d80bbb..1e0367475a4c 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -134,15 +134,18 @@ void key_user_put(struct key_user *user) * Allocate a serial number for a key. These are assigned randomly to avoid * security issues through covert channel problems. */ -static inline void key_alloc_serial(struct key *key) +static inline int key_alloc_serial(struct key *key) { struct rb_node *parent, **p; struct key *xkey; + int ret; /* propose a random serial number and look for a hole for it in the * serial number tree */ do { - get_random_bytes(&key->serial, sizeof(key->serial)); + ret = get_random_bytes_wait(&key->serial, sizeof(key->serial)); + if (unlikely(ret)) + return ret; key->serial >>= 1; /* negative numbers are not permitted */ } while (key->serial < 3); @@ -170,7 +173,7 @@ static inline void key_alloc_serial(struct key *key) rb_insert_color(&key->serial_node, &key_serial_tree); spin_unlock(&key_serial_lock); - return; + return 0; /* we found a key with the proposed serial number - walk the tree from * that point looking for the next unused serial number */ @@ -314,7 +317,9 @@ struct key *key_alloc(struct key_type *type, const char *desc, /* publish the key by giving it a serial number */ atomic_inc(&user->nkeys); - key_alloc_serial(key); + ret = key_alloc_serial(key); + if (ret < 0) + goto security_error; error: return key;