From patchwork Tue Jun 26 13:15:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10489065 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 C78A7602D8 for ; Tue, 26 Jun 2018 13:33:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A428E28931 for ; Tue, 26 Jun 2018 13:33:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 973C428942; Tue, 26 Jun 2018 13:33:09 +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=-2.9 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, DKIM_VALID, MAILING_LIST_MULTI autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 1822B28931 for ; Tue, 26 Jun 2018 13:33:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=ZvPh6X/TKra8Ictdzb6oB7erqLlR5CExpkLvf4VdChw=; b=q8co9ClwtRKD7xPLQfXBmHNrjc 59SqaHXK0z5/vMvQ50cQQQ01ei+WlOTxu5EoI8pr/SkqKWNRJ6piHJKiCYZCCfCJ1HltVGENWZ6us HlKFXom6lEzQTDOe4Y0SvAhSDA08L1BczT+JYG3kDs2S/8cJvIvY8T4mNoerMH/3KmUXrwUFyUuwB iB8lxVYPIvyAb2Mj+izQ8czqrDw9xO9lssuVDesJFqt/gMTF/q6GQ1QI/Msux/hNBe8E+/gT5tnfq wOiPY7R+dQnULnfZH9ihtJ+4E3PFf3b8nc1TFF/9Nz0LR/KKU+s9qr8+cQaZIyev4h/k4ygTzB3Eq Az+Dy8pA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fXo5Y-00014M-8v; Tue, 26 Jun 2018 13:32:56 +0000 Received: from mail-wr0-x243.google.com ([2a00:1450:400c:c0c::243]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fXnpL-0007Jn-Ir for linux-arm-kernel@lists.infradead.org; Tue, 26 Jun 2018 13:16:31 +0000 Received: by mail-wr0-x243.google.com with SMTP id k6-v6so17224858wrp.4 for ; Tue, 26 Jun 2018 06:16:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=EP2Dki4EWWZ2WEvc6M+bB9+4bOXHIe54Gcv4T4SHLRg=; b=tP3T9GZTcDl6sqUhST8VsnHchEalIHYPswEFU9VUy7f9t1zbWyFcTLdS0psY+d4o/v ANdg4IwZfzGL5HClnDgybjyli/txaY22L/ymiTvnVDZpW1HrKlHsQLWSIfsXpBJItKWN zo//HeueKsd5yERZIV1bDSpwQQa0iRqD6VlwduoonlUmoyuJEHEwNvpUM6QuSBP60Uir ts/hFjdrUyd1Ix8BBh8ZYP6xGFbbpSOWuYcCkYyfCZDnOvgeRqOdk/fNn30c6tqdVLpX X+PmiFnO/EFnY37ufjibH598VtfKS2SjQ++OW5uhG52javBmd+D4MiE6X6/yjqD8qe/Q MDqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=EP2Dki4EWWZ2WEvc6M+bB9+4bOXHIe54Gcv4T4SHLRg=; b=EiJ9smPcm77OvIHJJ3pl+5Go4RD9iqPoN637yshDqCIzTEA+MY/LLxZq20vMOZOEsb RNYZiPe7S1GeFUzcoZI/jR9DGGMIeovx2u7WuKTOxSshak5DtMoBRxq3umkd27qnLQzZ oixRIO2Er7V8w68HXb0j0Qoi+mJTsbbkO1h1sLYIa3iHjDoQXxGrBzfEYmzqQI0uY27O OeVv6WlCyJB6WpWz7pzD52UfpzCiUgg5R+PaRuNYn+eMvEHrpFAxQRbGkdUv1qZZBQ4i WQ0t4JBUmDJyYAiIaz2dzSYYPINh0TG4PWO8LUw9fl7WtgwifVVl9/pQoeaE6fje90v9 RFig== X-Gm-Message-State: APt69E3h18CV8/4jrfRGOSha53fCiGooOGg/90sg6224DGblk74bpxW3 s4YfOIZSU2DjQQMnE21+YMyEmA== X-Google-Smtp-Source: AAOMgpcwLC6WteD5eQOoz/gQ/wmnxQoEg1Rjd3LVuSQVs2Xf+NomWpZHfIoqNwGgvQayzaQdkoEUqQ== X-Received: by 2002:adf:81ca:: with SMTP id 68-v6mr1426498wra.44.1530018959149; Tue, 26 Jun 2018 06:15:59 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id w15-v6sm2162639wrn.25.2018.06.26.06.15.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Jun 2018 06:15:58 -0700 (PDT) From: Andrey Konovalov To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Catalin Marinas , Will Deacon , Christoph Lameter , Andrew Morton , Mark Rutland , Nick Desaulniers , Marc Zyngier , Dave Martin , Ard Biesheuvel , "Eric W . Biederman" , Ingo Molnar , Paul Lawrence , Geert Uytterhoeven , Arnd Bergmann , "Kirill A . Shutemov" , Greg Kroah-Hartman , Kate Stewart , Mike Rapoport , kasan-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sparse@vger.kernel.org, linux-mm@kvack.org, linux-kbuild@vger.kernel.org Subject: [PATCH v4 14/17] khwasan, arm64: add brk handler for inline instrumentation Date: Tue, 26 Jun 2018 15:15:24 +0200 Message-Id: <69fd53d114e5814020e5e265ae451a63b09c776e.1530018818.git.andreyknvl@google.com> X-Mailer: git-send-email 2.18.0.rc2.346.g013aa6912e-goog In-Reply-To: References: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180626_061611_671210_3BE8BFDE X-CRM114-Status: GOOD ( 23.34 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chintan Pandya , Jacob Bramley , Jann Horn , Ruben Ayrapetyan , Andrey Konovalov , Lee Smith , Kostya Serebryany , Mark Brand , Ramana Radhakrishnan , Evgeniy Stepanov MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP KHWASAN inline instrumentation mode (which embeds checks of shadow memory into the generated code, instead of inserting a callback) generates a brk instruction when a tag mismatch is detected. This commit add a KHWASAN brk handler, that decodes the immediate value passed to the brk instructions (to extract information about the memory access that triggered the mismatch), reads the register values (x0 contains the guilty address) and reports the bug. Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/brk-imm.h | 2 + arch/arm64/kernel/traps.c | 69 +++++++++++++++++++++++++++++++- 2 files changed, 69 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/brk-imm.h b/arch/arm64/include/asm/brk-imm.h index ed693c5bcec0..e4a7013321dc 100644 --- a/arch/arm64/include/asm/brk-imm.h +++ b/arch/arm64/include/asm/brk-imm.h @@ -16,10 +16,12 @@ * 0x400: for dynamic BRK instruction * 0x401: for compile time BRK instruction * 0x800: kernel-mode BUG() and WARN() traps + * 0x9xx: KHWASAN trap (allowed values 0x900 - 0x9ff) */ #define FAULT_BRK_IMM 0x100 #define KGDB_DYN_DBG_BRK_IMM 0x400 #define KGDB_COMPILED_DBG_BRK_IMM 0x401 #define BUG_BRK_IMM 0x800 +#define KHWASAN_BRK_IMM 0x900 #endif diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index d399d459397b..95152a4fd202 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -269,10 +270,14 @@ void arm64_notify_die(const char *str, struct pt_regs *regs, } } -void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) +void __arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) { regs->pc += size; +} +void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) +{ + __arm64_skip_faulting_instruction(regs, size); /* * If we were single stepping, we want to get the step exception after * we return from the trap. @@ -791,7 +796,7 @@ static int bug_handler(struct pt_regs *regs, unsigned int esr) } /* If thread survives, skip over the BUG instruction and continue: */ - arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + __arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); return DBG_HOOK_HANDLED; } @@ -801,6 +806,59 @@ static struct break_hook bug_break_hook = { .fn = bug_handler, }; +#ifdef CONFIG_KASAN_HW + +#define KHWASAN_ESR_RECOVER 0x20 +#define KHWASAN_ESR_WRITE 0x10 +#define KHWASAN_ESR_SIZE_MASK 0x0f +#define KHWASAN_ESR_SIZE(esr) (1 << ((esr) & KHWASAN_ESR_SIZE_MASK)) + +static int khwasan_handler(struct pt_regs *regs, unsigned int esr) +{ + bool recover = esr & KHWASAN_ESR_RECOVER; + bool write = esr & KHWASAN_ESR_WRITE; + size_t size = KHWASAN_ESR_SIZE(esr); + u64 addr = regs->regs[0]; + u64 pc = regs->pc; + + if (user_mode(regs)) + return DBG_HOOK_ERROR; + + kasan_report(addr, size, write, pc); + + /* + * The instrumentation allows to control whether we can proceed after + * a crash was detected. This is done by passing the -recover flag to + * the compiler. Disabling recovery allows to generate more compact + * code. + * + * Unfortunately disabling recovery doesn't work for the kernel right + * now. KHWASAN reporting is disabled in some contexts (for example when + * the allocator accesses slab object metadata; same is true for KASAN; + * this is controlled by current->kasan_depth). All these accesses are + * detected by the tool, even though the reports for them are not + * printed. + * + * This is something that might be fixed at some point in the future. + */ + if (!recover) + die("Oops - KHWASAN", regs, 0); + + /* If thread survives, skip over the brk instruction and continue: */ + __arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); + return DBG_HOOK_HANDLED; +} + +#define KHWASAN_ESR_VAL (0xf2000000 | KHWASAN_BRK_IMM) +#define KHWASAN_ESR_MASK 0xffffff00 + +static struct break_hook khwasan_break_hook = { + .esr_val = KHWASAN_ESR_VAL, + .esr_mask = KHWASAN_ESR_MASK, + .fn = khwasan_handler, +}; +#endif + /* * Initial handler for AArch64 BRK exceptions * This handler only used until debug_traps_init(). @@ -808,6 +866,10 @@ static struct break_hook bug_break_hook = { int __init early_brk64(unsigned long addr, unsigned int esr, struct pt_regs *regs) { +#ifdef CONFIG_KASAN_HW + if ((esr & KHWASAN_ESR_MASK) == KHWASAN_ESR_VAL) + return khwasan_handler(regs, esr) != DBG_HOOK_HANDLED; +#endif return bug_handler(regs, esr) != DBG_HOOK_HANDLED; } @@ -815,4 +877,7 @@ int __init early_brk64(unsigned long addr, unsigned int esr, void __init trap_init(void) { register_break_hook(&bug_break_hook); +#ifdef CONFIG_KASAN_HW + register_break_hook(&khwasan_break_hook); +#endif }