From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZqq0ocBY1PaZDhB9/Q+sG8XsdHN1n+1slJQSNCyN6LBjOzYLOnm8p7tNklGegAmzPZy72Hl ARC-Seal: i=1; a=rsa-sha256; t=1526426293; cv=none; d=google.com; s=arc-20160816; b=QHnRJTSbrQr8LvLLmPr9kmEHH+A/DjPMozKvVj8oVolxJ/+kpiSxUfaNl7jUTSq1zg kacCXVfwhbjZr0m8xvkM9KrmD4YlXvAQsLOy8f/ytWPrwSaCKlkk2fRhGELFEkhipVz/ 3o+BEZ/2NinCOPKWutHYBTrm6BK0nV0gxKnU6DGD4L8B2VzxpBwVFKJQRefzpgiosMFJ lzuiPEV98Rs7hWRX0JeK9NjF2BJl686dMq2le36Kv3xpD5qjyYAqTlvWGRhczfcxN3+E 2KIFmwPPNjFo7OW3/cvZPvl/7iGeQUlI5JfnsrbmIQPr73T2fhmnEZHncEd7Mt83yGal s7AQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:dkim-signature:arc-authentication-results; bh=WGmCoyZw6kfQig0vmyrnjLAxcK/WAAtSlqoT6hKcZCs=; b=XSgrxqyQcm9R/6hAVDqXgd6BtCQIR18R3NUL7o7cdKsyCxXQCwmJf8epj4Fh4ItKdL OQZED+/EHwVLwqBTbfnynri6mIRKzJposzTwJuRnGmdFTHXVoNVOKqcpQOowcWDTWBWS D8pYwYZE53JhC/z3+yK+QZD0wSIOV0lITIht3+Rwh5zjxow+leD73GmqZVuBiDx85c5b QjVN3AQMfoj+yWM1XOTnn+IAVQ9nLtw8o38u26WM5qARqMdgW8oJriibEdbq/x0QnPfd nsJZNlkd2SWcaOvJFGcCofX9XiwthUqjeA+wT0yHByT5GXcBj8XP3VdcfK3f3lK1hk6T QKTQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@tobin.cc header.s=fm3 header.b=IVlASwN1; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=WNa6TPVj; spf=neutral (google.com: 66.111.4.26 is neither permitted nor denied by best guess record for domain of me@tobin.cc) smtp.mailfrom=me@tobin.cc Authentication-Results: mx.google.com; dkim=pass header.i=@tobin.cc header.s=fm3 header.b=IVlASwN1; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b=WNa6TPVj; spf=neutral (google.com: 66.111.4.26 is neither permitted nor denied by best guess record for domain of me@tobin.cc) smtp.mailfrom=me@tobin.cc X-ME-Sender: From: "Tobin C. Harding" To: "Theodore Ts'o" Cc: "Tobin C. Harding" , Linus Torvalds , Randy Dunlap , Steven Rostedt , Kees Cook , Anna-Maria Gleixner , Andrew Morton , Greg Kroah-Hartman , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: [PATCH v5 3/3] vsprintf: Use hw RNG for ptr_key Date: Wed, 16 May 2018 09:17:39 +1000 Message-Id: <1526426259-23012-4-git-send-email-me@tobin.cc> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1526426259-23012-1-git-send-email-me@tobin.cc> References: <1526426259-23012-1-git-send-email-me@tobin.cc> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600497770894213434?= X-GMAIL-MSGID: =?utf-8?q?1600573976593127048?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Currently we must wait for enough entropy to become available before hashed pointers can be printed. We can remove this wait by using the hw RNG if available. Use hw RNG to get keying material. Suggested-by: Kees Cook Signed-off-by: Tobin C. Harding Reviewed-by: Steven Rostedt (VMware) --- lib/vsprintf.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index b82f0c6c2aec..a1567dd7066c 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1657,9 +1657,8 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, static bool have_filled_random_ptr_key __read_mostly; static siphash_key_t ptr_key __read_mostly; -static void fill_random_ptr_key(struct random_ready_callback *unused) +static void ptr_key_ready(void) { - get_random_bytes(&ptr_key, sizeof(ptr_key)); /* * have_filled_random_ptr_key==true is dependent on get_random_bytes(). * ptr_to_id() needs to see have_filled_random_ptr_key==true @@ -1669,14 +1668,28 @@ static void fill_random_ptr_key(struct random_ready_callback *unused) WRITE_ONCE(have_filled_random_ptr_key, true); } +static void fill_random_ptr_key(struct random_ready_callback *unused) +{ + get_random_bytes(&ptr_key, sizeof(ptr_key)); + ptr_key_ready(); +} + static struct random_ready_callback random_ready = { .func = fill_random_ptr_key }; static int __init initialize_ptr_random(void) { - int ret = add_random_ready_callback(&random_ready); + int key_size = sizeof(ptr_key); + int ret; + + /* Use hw RNG if available */ + if (get_random_bytes_arch(&ptr_key, key_size) == key_size) { + ptr_key_ready(); + return 0; + } + ret = add_random_ready_callback(&random_ready); if (!ret) { return 0; } else if (ret == -EALREADY) { -- 2.7.4