From patchwork Mon Nov 19 17:26:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10689059 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A378414E2 for ; Mon, 19 Nov 2018 17:28:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 87ADB2A2D1 for ; Mon, 19 Nov 2018 17:28:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7B8FE2A2E1; Mon, 19 Nov 2018 17:28:01 +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=-10.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C98D72A2D1 for ; Mon, 19 Nov 2018 17:28:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC46B6B1B98; Mon, 19 Nov 2018 12:27:30 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id E9AF86B1B99; Mon, 19 Nov 2018 12:27:30 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C52966B1B9A; Mon, 19 Nov 2018 12:27:30 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by kanga.kvack.org (Postfix) with ESMTP id 6BD356B1B98 for ; Mon, 19 Nov 2018 12:27:30 -0500 (EST) Received: by mail-wm1-f70.google.com with SMTP id r137-v6so13796889wmb.0 for ; Mon, 19 Nov 2018 09:27:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=wBF5UF4+9Mv4z7HvvYvHo19YeCHdsuE1+in1R6vNAJ0=; b=qjm0ljBSC6/8yFRVvFiZwmPp3i+JTHUnqNBvLW8GN4EYSCi9rOp6wj6R4JxGkZV8h2 /Kf2FLO7Wl52TbcDHAhq+6GoBVcOvx6jGYS7uLQE8FpmDw0KSN2taI25Cm8+7I8mtxJM FVupc2ntGFHIyN4ayIYBoJxCGvuWlFfm/9ueClE0gDUcyNcD0OsgD/fvxHmGJpvdIyIJ YK/hmhDONFBIfdsoWdwyOJJo19VcSViTy0GwS/0ICHXSm+vdnLzD49IbpXETfIcCNzip M4CUmbGnEs+//GxSnD3NYQrOMfycoPqUQOL5FMRr77oEJCfhBk1FVywV0qKZfxyOJXmp rGlA== X-Gm-Message-State: AGRZ1gLXRXL7SeTEV5v+VBGGDwWYSvRBEnbtYKIkUjlNE2TiJdEdUWS0 B2NWFmq55JiW1skznJTjC/vvesJEz6+FoWivYHfpba8BCGT9ITdn1UdOSJv+VZZzA7aQbjv0s7B pRHAcXSBvrCWo27wF0ZecbeUNSG+nV8TDYIMURBJrc3isJAiygl1d48ALasD27Mfyv89EWuGwUr BtMhwT4tJa0D6/YdpU1oAxdvNBsohpu/HWWtvWvNF+vFN8m51Ba8rTeS7xGup/mY/wKZcoaBLFH A8JcyAdz/rjPUlNgsKX8O5Z7uBdmbdUxxlRm6PQ5IJ7xaYdee9+0iz4jsynwSfwG+EnsavfIFbs 98TPnVRr03w2KHTh8ofUbvDmY4b2Mzr2R0NrbD/Ji+MvOTSUqCwn+nz+TTOJIJiwMvEALbUC+VB q X-Received: by 2002:a1c:ae05:: with SMTP id x5mr2709282wme.137.1542648449943; Mon, 19 Nov 2018 09:27:29 -0800 (PST) X-Received: by 2002:a1c:ae05:: with SMTP id x5mr2709239wme.137.1542648448914; Mon, 19 Nov 2018 09:27:28 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1542648448; cv=none; d=google.com; s=arc-20160816; b=z3rHfDGCtItGkHvX/2SAH3yNNqBvATV4adZuoprcT/AKFSzDvsSpekg1VghjF47Tgx MU8WeLACvNGZIT4ztp9jQftMJ++WviECqKuW3r86dw0TiYtY2aTHuG28cDWlE6Bho5La 8tYliQEI6TpYRysxhyugpCO+F3wjgAcMIs580EEtFDQOvw1kxq2aR+zxIfr+TqcrNXsW LNKl/OZXcQh5xKEPnreUshXjpFgil6rZbcPBOcOKHVFOKiy/lYW7soBuFB37UiJQc0d8 Y9g9Im2j68ztQjocLWfenALgll2zk38vWrPhlDwgMWoLg1usTRZfwNw+lla9UqR2FvEi rRxQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature; bh=wBF5UF4+9Mv4z7HvvYvHo19YeCHdsuE1+in1R6vNAJ0=; b=Z1M94SR8zWkDbUplFtomvvhOrDLMPyqoJE7QxIS1yeFOOknKQCZpT+l/MUFrN7AmUw QNejkPKrxz7Mqwk5bh2xNoFZZqUX159T3qElD2N7qMrKXfTsK1wY6abXNdw/0Bw06Cyd WNi9kk/Zmq4lbuo6eR24FUtE88TwcO38UP+ODiUA+PbI3ju7W0I9yZjZIMBflP9h7nVo O50Z6h3ifZMf9BDEnoN/h6Zy/cz0Ybe1HEayqn00TO1zn+6LHxL36TfUIVTfTLINUIC6 AAu1YG9OPfQqs+FgvxSHMFy+8KvZ10MH7TMifFbujKh96pPLbLjKzhK7PdZwV7XK+7y1 xxpQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=hJw352I0; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n15-v6sor19244582wmd.2.2018.11.19.09.27.28 for (Google Transport Security); Mon, 19 Nov 2018 09:27:28 -0800 (PST) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=hJw352I0; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com 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 :mime-version:content-transfer-encoding; bh=wBF5UF4+9Mv4z7HvvYvHo19YeCHdsuE1+in1R6vNAJ0=; b=hJw352I0VKmInsCOkuELsOv+Pahph8JfJ73CQXAZKCXN65JnrmcZlGzURxPmgXvG3g QazJpRBIHupHzYPfP7MYb0PuKhph+X1s8OpuF8UpSC4mgWmjWvNRznIWGSNoJFEYfVEu 99xZ8gRRopTUIz+9Me9DLsMKuJYtjyjZOtrg6wqtXK0h63pL4szujO0UI0L0daJy1NDq mVnQVySQ+v+H1rd/xXcoegJ2Gs7uXsMvxU5XAJoxOrFeFq5jDJZUBIl3MB4bV1DisWdE 3BLNXZajk3syornY+EfBF1om3yJE12IbjYbNel6kelBqvJ7+A5HKRDy/6d8eAm5ykh3K zlng== X-Google-Smtp-Source: AFSGD/UnIiLKI4KNAdCg4BuOwdkMDxbO6AUrlCl42nJ+mPUKPiATHpNbFPe96DXL5euEhW1+kxSToA== X-Received: by 2002:a1c:8c4d:: with SMTP id o74mr2767337wmd.134.1542648448371; Mon, 19 Nov 2018 09:27:28 -0800 (PST) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:3180:41f8:3010:ff61]) by smtp.gmail.com with ESMTPSA id l143-v6sm23685190wmb.23.2018.11.19.09.27.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Nov 2018 09:27:27 -0800 (PST) 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 Cc: Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Jann Horn , Mark Brand , Chintan Pandya , Vishwath Mohan , Andrey Konovalov Subject: [PATCH v11 20/24] kasan, arm64: add brk handler for inline instrumentation Date: Mon, 19 Nov 2018 18:26:36 +0100 Message-Id: <33d91a4f2ea70b7c58cdfbedb8042118b05eca30.1542648335.git.andreyknvl@google.com> X-Mailer: git-send-email 2.19.1.1215.g8438c0b245-goog In-Reply-To: References: MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Tag-based KASAN 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 adds a tag-based KASAN specific 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. Reviewed-by: Andrey Ryabinin Reviewed-by: Dmitry Vyukov Signed-off-by: Andrey Konovalov --- arch/arm64/include/asm/brk-imm.h | 2 + arch/arm64/kernel/traps.c | 68 +++++++++++++++++++++++++++++++- include/linux/kasan.h | 3 ++ 3 files changed, 71 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/brk-imm.h b/arch/arm64/include/asm/brk-imm.h index ed693c5bcec0..2945fe6cd863 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: tag-based KASAN 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 KASAN_BRK_IMM 0x900 #endif diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5f4d9acb32f5..04bdc53716ef 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -284,10 +285,14 @@ 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. @@ -959,7 +964,7 @@ 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; } @@ -969,6 +974,58 @@ static struct break_hook bug_break_hook = { .fn = bug_handler, }; +#ifdef CONFIG_KASAN_SW_TAGS + +#define KASAN_ESR_RECOVER 0x20 +#define KASAN_ESR_WRITE 0x10 +#define KASAN_ESR_SIZE_MASK 0x0f +#define KASAN_ESR_SIZE(esr) (1 << ((esr) & KASAN_ESR_SIZE_MASK)) + +static int kasan_handler(struct pt_regs *regs, unsigned int esr) +{ + bool recover = esr & KASAN_ESR_RECOVER; + bool write = esr & KASAN_ESR_WRITE; + size_t size = KASAN_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. KASAN reporting is disabled in some contexts (for example when + * the allocator accesses slab object metadata; 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 - KASAN", 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 KASAN_ESR_VAL (0xf2000000 | KASAN_BRK_IMM) +#define KASAN_ESR_MASK 0xffffff00 + +static struct break_hook kasan_break_hook = { + .esr_val = KASAN_ESR_VAL, + .esr_mask = KASAN_ESR_MASK, + .fn = kasan_handler, +}; +#endif + /* * Initial handler for AArch64 BRK exceptions * This handler only used until debug_traps_init(). @@ -976,6 +1033,10 @@ static struct break_hook bug_break_hook = { int __init early_brk64(unsigned long addr, unsigned int esr, struct pt_regs *regs) { +#ifdef CONFIG_KASAN_SW_TAGS + if ((esr & KASAN_ESR_MASK) == KASAN_ESR_VAL) + return kasan_handler(regs, esr) != DBG_HOOK_HANDLED; +#endif return bug_handler(regs, esr) != DBG_HOOK_HANDLED; } @@ -983,4 +1044,7 @@ int __init early_brk64(unsigned long addr, unsigned int esr, void __init trap_init(void) { register_break_hook(&bug_break_hook); +#ifdef CONFIG_KASAN_SW_TAGS + register_break_hook(&kasan_break_hook); +#endif } diff --git a/include/linux/kasan.h b/include/linux/kasan.h index a477ce2abdc9..8da7b7a4397a 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -173,6 +173,9 @@ void kasan_init_tags(void); void *kasan_reset_tag(const void *addr); +void kasan_report(unsigned long addr, size_t size, + bool is_write, unsigned long ip); + #else /* CONFIG_KASAN_SW_TAGS */ static inline void kasan_init_tags(void) { }