From patchwork Sun Oct 1 00:06:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tobin Harding X-Patchwork-Id: 9979605 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 C13C060327 for ; Sun, 1 Oct 2017 00:09:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B376927E63 for ; Sun, 1 Oct 2017 00:09:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A5D7A28D00; Sun, 1 Oct 2017 00:09:31 +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=-4.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, 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 C5E7927E63 for ; Sun, 1 Oct 2017 00:09:30 +0000 (UTC) Received: (qmail 7237 invoked by uid 550); 1 Oct 2017 00:09:24 -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 Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 32669 invoked from network); 1 Oct 2017 00:07:29 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tobin.cc; h=cc :date:from:in-reply-to:message-id:references:subject:to :x-me-sender:x-me-sender:x-sasl-enc:x-sasl-enc; s=fm1; bh=KJ/GWI L1X64/xXI2ZdtLgmXaP9ToVYoJGGctLemrWF8=; b=RXWM96DRHxdBrTkrBb6qhN geJ4bG8xGpCpdF+YZ4geG6cvXq2tDXA8ccKKHChZofCaVwYft/oKMoMtl+iCVAun nAlZD5HdScXFe14nL2zhEL+2xE3AJNGqLee6O8SPlnw1gMeaWjW+Fku6uH2RWqCz lTkYmD3uJQrW5QaTLxAhdFVHS/GjSA3oP7hX/3PtFRQ3VVMYyL9xGnQ+jAotZhAV MLEk+Q4LusXMYUKUsxVQdVamHTx+D/YMd2iA84VYNbCLEZrKJcVgBpmV+VLPfyAp 1+SPhvaMnoQnhCxxzbJop15xKw2l+HXdqdhBbamvsF619TlTtTLgdNKsyOkNWDRg == DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:date:from:in-reply-to:message-id :references:subject:to:x-me-sender:x-me-sender:x-sasl-enc :x-sasl-enc; s=fm1; bh=KJ/GWIL1X64/xXI2ZdtLgmXaP9ToVYoJGGctLemrW F8=; b=OVLbDNmCeLwABWRhoZiTG6rIJjrFUXibZU9/HDklkiYyzofz7kfxSaucQ DhzTLAJ8+51gkzchhNhYlxC0Oa4ZleFMN1Qyk+5K/3UPrjRpOTkTF/+Qo3WZvvsf 9leyJnREq5ZbXlJ4XArjSzee8I6ZhqK2r0oLt0QCTnTRd+SDn/9KEWK8tV8fi2LB IjXMobZjoVWnZWf7Ze8VGPxcgg71n6JWPS4Asny1Sy+UwNyFzf6+fz6Us32Q1LqQ 2rq9xTRnpzgqs2W5ZOkhGt/UjTPraM7rzQ1dOj1nINiy6rcMfkJvc/Ak3yit45BO Q3M7KwO2Jbuvih1m6ENJ8gH4+aXGQ== X-ME-Sender: X-Sasl-enc: fM07hdMPWPb+IHQBYeQuGJZ8TLiJQBwWXfxfdVZsrfAz 1506816437 From: "Tobin C. Harding" To: Greg KH , Petr Mladek , Joe Perches , Ian Campbell , Sergey Senozhatsky Cc: "Tobin C. Harding" , kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , Steven Rostedt , William Roberts , Chris Fries , Dave Weinstein Date: Sun, 1 Oct 2017 11:06:47 +1100 Message-Id: <1506816410-10230-4-git-send-email-me@tobin.cc> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1506816410-10230-1-git-send-email-me@tobin.cc> References: <1506816410-10230-1-git-send-email-me@tobin.cc> Subject: [kernel-hardening] [RFC V2 3/6] lib: vsprintf: physical address kernel pointer filtering options X-Virus-Scanned: ClamAV using ClamSMTP Add the kptr_restrict setting of 4 which results in %pa and %p[rR] values being cleansed. Address types printed with %pa are replaced by zeros. Resources printed with %p[rR] have the starting address replaced by zeros, resource size is still shown. Signed-off-by: Tobin C. Harding Signed-off-by: Greg Kroah-Hartman --- Documentation/sysctl/kernel.txt | 5 +++++ kernel/sysctl.c | 3 +-- lib/vsprintf.c | 31 +++++++++++++++++++++++++++++-- 3 files changed, 35 insertions(+), 4 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 7ee183af..b6d45bc 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -398,6 +398,11 @@ When kptr_restrict is set to (3), kernel pointers printed using %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. + ============================================================== l2cr: (PPC only) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 37ba637..f777b32 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 @@ -852,7 +851,7 @@ 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 e6eace0..0271223 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -406,6 +406,22 @@ static inline int kptr_restrict_cleanse_kernel_pointers(void) return kptr_restrict >= 3; } +/* + * return non-zero if we should cleanse pointers for %pa* specifiers. + */ +static inline int kptr_restrict_cleanse_addresses(void) +{ + return kptr_restrict >= 4; +} + +/* + * return non-zero if we should cleanse pointers for %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) @@ -758,6 +774,7 @@ 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++ = '['; @@ -785,10 +802,11 @@ 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) { @@ -1391,6 +1409,9 @@ char *address_val(char *buf, char *end, const void *addr, const char *fmt) break; } + if (kptr_restrict_cleanse_addresses()) + num = 0UL; + return special_hex_number(buf, end, num, size); } @@ -1714,6 +1735,12 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, * pointer to the real address. * * 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,