From patchwork Sat May 6 04:07:20 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 9714533 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 C72EC60234 for ; Sat, 6 May 2017 04:07:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B8F8F281B7 for ; Sat, 6 May 2017 04:07:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ABCE728678; Sat, 6 May 2017 04:07:44 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED 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 BE3C2281B7 for ; Sat, 6 May 2017 04:07:43 +0000 (UTC) Received: (qmail 25666 invoked by uid 550); 6 May 2017 04:07:42 -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 25637 invoked from network); 6 May 2017 04:07:40 -0000 Date: Fri, 5 May 2017 21:07:20 -0700 From: Greg KH To: kernel-hardening@lists.openwall.com, Petr Mladek , Sergey Senozhatsky Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Steven Rostedt , William Roberts , Chris Fries , Dave Weinstein Message-ID: <20170506040720.GD32707@kroah.com> References: <20170506040641.GA32707@kroah.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170506040641.GA32707@kroah.com> User-Agent: Mutt/1.8.2 (2017-04-18) Subject: [kernel-hardening] [RFC 3/6] lib: vsprintf: physical address kernel pointer filtering options X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Weinstein Add the kptr_restrict setting of 4 which results in %pa and %p[rR] values being replaced by zeros. Cc: William Roberts Cc: Chris Fries Signed-off-by: Dave Weinstein Signed-off-by: Greg Kroah-Hartman --- Documentation/sysctl/kernel.txt | 8 +++++++- kernel/sysctl.c | 3 +-- lib/vsprintf.c | 33 ++++++++++++++++++++++++++++++--- 3 files changed, 38 insertions(+), 6 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index c9f5da409868..df069ec42e4a 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -393,7 +393,13 @@ When kptr_restrict is set to (2), kernel pointers printed using %pK will be replaced with 0's regardless of privileges. When kptr_restrict is set to (3), kernel pointers printed using -%p and %pK will be replaced with 0's regardless of privileges. +%p and %pK will be replaced with 0's regardless of privileges, +however kernel pointers printed using %pP will continue to be printed. + +When kptr_restrict is set to (4), kernel pointers printed with +%p, %pK, %pa, and %p[rR] will be replaced with 0's regardless of +privileges. Kernel pointers printed using %pP will continue to be +printed. ============================================================== diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1bfdd262c66a..acf7e6cb00b4 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -129,7 +129,6 @@ static unsigned long one_ul = 1; static int one_hundred = 100; static int one_thousand = 1000; #ifdef CONFIG_PRINTK -static int three = 3; static int ten_thousand = 10000; #endif #ifdef CONFIG_PERF_EVENTS @@ -831,7 +830,7 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax_sysadmin, .extra1 = &zero, - .extra2 = &three, + .extra2 = &four, }, #endif { diff --git a/lib/vsprintf.c b/lib/vsprintf.c index f4e11dade1ab..75a49795fcae 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -405,6 +405,22 @@ static inline int kptr_restrict_always_cleanse_pointers(void) return kptr_restrict >= 3; } +/* + * Always cleanse physical addresses (%pa* specifiers) + */ +static inline int kptr_restrict_cleanse_addresses(void) +{ + return kptr_restrict >= 4; +} + +/* + * Always cleanse resource addresses (%p[rR] specifiers) + */ +static inline int kptr_restrict_cleanse_resources(void) +{ + return kptr_restrict >= 4; +} + static noinline_for_stack char *number(char *buf, char *end, unsigned long long num, struct printf_spec spec) @@ -757,6 +773,7 @@ char *resource_string(char *buf, char *end, struct resource *res, char *p = sym, *pend = sym + sizeof(sym); int decode = (fmt[0] == 'R') ? 1 : 0; + int cleanse = kptr_restrict_cleanse_resources(); const struct printf_spec *specp; *p++ = '['; @@ -784,10 +801,11 @@ char *resource_string(char *buf, char *end, struct resource *res, p = string(p, pend, "size ", str_spec); p = number(p, pend, resource_size(res), *specp); } else { - p = number(p, pend, res->start, *specp); + p = number(p, pend, cleanse ? 0UL : res->start, *specp); if (res->start != res->end) { *p++ = '-'; - p = number(p, pend, res->end, *specp); + p = number(p, pend, cleanse ? + res->end - res->start : res->end, *specp); } } if (decode) { @@ -1390,7 +1408,9 @@ char *address_val(char *buf, char *end, const void *addr, const char *fmt) break; } - return special_hex_number(buf, end, num, size); + return special_hex_number(buf, end, + kptr_restrict_cleanse_addresses() ? 0UL : num, + size); } static noinline_for_stack @@ -1581,6 +1601,12 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt) * * Note: That for kptr_restrict set to 3, %p and %pK have the same * meaning. + * + * Note: That for kptr_restrict set to 4, %pa will null out the physical + * address. + * + * Note: That for kptr_restrict set to 4, %p[rR] will null out the memory + * address. */ static noinline_for_stack char *pointer(const char *fmt, char *buf, char *end, void *ptr, @@ -1738,6 +1764,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, } case 2: /* restrict only %pK */ case 3: /* restrict all non-extensioned %p and %pK */ + case 4: /* restrict all non-extensioned %p, %pK, %pa*, %p[rR] */ default: ptr = NULL; break;