From patchwork Tue Nov 18 06:19:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5325711 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CE164C11AC for ; Tue, 18 Nov 2014 06:26:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 92A1220165 for ; Tue, 18 Nov 2014 06:26:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 800FA20160 for ; Tue, 18 Nov 2014 06:26:05 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XqcD7-0001RV-Tq; Tue, 18 Nov 2014 06:24:21 +0000 Received: from szxga01-in.huawei.com ([119.145.14.64]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XqcCm-00011g-55 for linux-arm-kernel@lists.infradead.org; Tue, 18 Nov 2014 06:24:01 +0000 Received: from 172.24.2.119 (EHLO lggeml422-hub.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CEP22157; Tue, 18 Nov 2014 14:22:42 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml422-hub.china.huawei.com (10.72.61.32) with Microsoft SMTP Server id 14.3.158.1; Tue, 18 Nov 2014 14:22:29 +0800 From: Wang Nan To: , , , , , , , , , Subject: [PATCH v2 3/3] ARM: kprobes: disallow probing stack consuming instructions Date: Tue, 18 Nov 2014 14:19:42 +0800 Message-ID: <1416291582-74982-4-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1416291582-74982-1-git-send-email-wangnan0@huawei.com> References: <1416291582-74982-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141117_222400_756782_C0E3C870 X-CRM114-Status: GOOD ( 13.73 ) X-Spam-Score: -0.7 (/) Cc: lizefan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch prohibit probing instructions for which the stack requirement are unable to be determined statically. Some test cases are found not work again after the modification, this patch also removes them. v1 -> v2: - Use MAX_STACK_SIZE macro instead of hard coded stack size. Signed-off-by: Wang Nan --- arch/arm/include/asm/kprobes.h | 1 - arch/arm/include/asm/probes.h | 12 ++++++++++++ arch/arm/kernel/entry-armv.S | 3 ++- arch/arm/kernel/kprobes-test-arm.c | 16 ++++++++++------ arch/arm/kernel/kprobes.c | 9 +++++++++ 5 files changed, 33 insertions(+), 8 deletions(-) diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h index 49fa0df..56f9ac6 100644 --- a/arch/arm/include/asm/kprobes.h +++ b/arch/arm/include/asm/kprobes.h @@ -22,7 +22,6 @@ #define __ARCH_WANT_KPROBES_INSN_SLOT #define MAX_INSN_SIZE 2 -#define MAX_STACK_SIZE 64 /* 32 would probably be OK */ #define flush_insn_slot(p) do { } while (0) #define kretprobe_blacklist_size 0 diff --git a/arch/arm/include/asm/probes.h b/arch/arm/include/asm/probes.h index ccf9af3..f0a1ee8 100644 --- a/arch/arm/include/asm/probes.h +++ b/arch/arm/include/asm/probes.h @@ -19,6 +19,8 @@ #ifndef _ASM_PROBES_H #define _ASM_PROBES_H +#ifndef __ASSEMBLY__ + typedef u32 probes_opcode_t; struct arch_probes_insn; @@ -41,4 +43,14 @@ struct arch_probes_insn { int stack_space; }; +#endif /* __ASSEMBLY__ */ + +/* + * We assume one instruction can consume at most 64 bytes stack, which is + * 'push {r0-r15}'. Instructions consume more or unknown stack space like + * 'str r0, [sp, #-80]' and 'str r0, [sp, r1]' should be prohibit to probe. + * Both kprobe and jprobe use this macro. + */ +#define MAX_STACK_SIZE 64 + #endif diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 2f5555d..672b219 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -31,6 +31,7 @@ #include "entry-header.S" #include +#include /* * Interrupt handling. @@ -249,7 +250,7 @@ __und_svc: @ If a kprobe is about to simulate a "stmdb sp..." instruction, @ it obviously needs free stack space which then will belong to @ the saved context. - svc_entry 64 + svc_entry MAX_STACK_SIZE #else svc_entry #endif diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c index cb14242..d8ad5bb 100644 --- a/arch/arm/kernel/kprobes-test-arm.c +++ b/arch/arm/kernel/kprobes-test-arm.c @@ -476,7 +476,8 @@ void kprobe_arm_test_cases(void) TEST_GROUP("Extra load/store instructions") TEST_RPR( "strh r",0, VAL1,", [r",1, 48,", -r",2, 24,"]") - TEST_RPR( "streqh r",14,VAL2,", [r",13,0, ", r",12, 48,"]") + TEST_RPR( "streqh r",14,VAL2,", [r",11,0, ", r",12, 48,"]") + TEST_UNSUPPORTED( "streqh r14, [r13, r12]") TEST_RPR( "strh r",1, VAL1,", [r",2, 24,", r",3, 48,"]!") TEST_RPR( "strneh r",12,VAL2,", [r",11,48,", -r",10,24,"]!") TEST_RPR( "strh r",2, VAL1,", [r",3, 24,"], r",4, 48,"") @@ -565,7 +566,8 @@ void kprobe_arm_test_cases(void) #if __LINUX_ARM_ARCH__ >= 5 TEST_RPR( "strd r",0, VAL1,", [r",1, 48,", -r",2,24,"]") - TEST_RPR( "strccd r",8, VAL2,", [r",13,0, ", r",12,48,"]") + TEST_RPR( "strccd r",8, VAL2,", [r",11,0, ", r",12,48,"]") + TEST_UNSUPPORTED( "strccd r8, [r13, r12]") TEST_RPR( "strd r",4, VAL1,", [r",2, 24,", r",3, 48,"]!") TEST_RPR( "strcsd r",12,VAL2,", [r",11,48,", -r",10,24,"]!") TEST_RPR( "strd r",2, VAL1,", [r",5, 24,"], r",4,48,"") @@ -638,13 +640,15 @@ void kprobe_arm_test_cases(void) TEST_RP( "str"byte" r",2, VAL1,", [r",3, 24,"], #48") \ TEST_RP( "str"byte" r",10,VAL2,", [r",9, 64,"], #-48") \ TEST_RPR("str"byte" r",0, VAL1,", [r",1, 48,", -r",2, 24,"]") \ - TEST_RPR("str"byte" r",14,VAL2,", [r",13,0, ", r",12, 48,"]") \ + TEST_RPR("str"byte" r",14,VAL2,", [r",11,0, ", r",12, 48,"]") \ + TEST_UNSUPPORTED("str"byte" r14, [r13, r12]") \ TEST_RPR("str"byte" r",1, VAL1,", [r",2, 24,", r",3, 48,"]!") \ TEST_RPR("str"byte" r",12,VAL2,", [r",11,48,", -r",10,24,"]!") \ TEST_RPR("str"byte" r",2, VAL1,", [r",3, 24,"], r",4, 48,"") \ TEST_RPR("str"byte" r",10,VAL2,", [r",9, 48,"], -r",11,24,"") \ TEST_RPR("str"byte" r",0, VAL1,", [r",1, 24,", r",2, 32,", asl #1]")\ - TEST_RPR("str"byte" r",14,VAL2,", [r",13,0, ", r",12, 32,", lsr #2]")\ + TEST_RPR("str"byte" r",14,VAL2,", [r",11,0, ", r",12, 32,", lsr #2]")\ + TEST_UNSUPPORTED("str"byte" r14, [r13, r12, lsr #2]")\ TEST_RPR("str"byte" r",1, VAL1,", [r",2, 24,", r",3, 32,", asr #3]!")\ TEST_RPR("str"byte" r",12,VAL2,", [r",11,24,", r",10, 4,", ror #31]!")\ TEST_P( "ldr"byte" r0, [r",0, 24,", #-2]") \ @@ -668,12 +672,12 @@ void kprobe_arm_test_cases(void) LOAD_STORE("") TEST_P( "str pc, [r",0,0,", #15*4]") - TEST_R( "str pc, [sp, r",2,15*4,"]") + TEST_UNSUPPORTED( "str pc, [sp, r2]") TEST_BF( "ldr pc, [sp, #15*4]") TEST_BF_R("ldr pc, [sp, r",2,15*4,"]") TEST_P( "str sp, [r",0,0,", #13*4]") - TEST_R( "str sp, [sp, r",2,13*4,"]") + TEST_UNSUPPORTED( "str sp, [sp, r2]") TEST_BF( "ldr sp, [sp, #13*4]") TEST_BF_R("ldr sp, [sp, r",2,13*4,"]") diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index d7bee4b..30498436 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -115,6 +115,15 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) break; } + /* + * Never instrument insn like 'str r0, [sp, +/-r1]'. Also, insn likes + * 'str r0, [sp, #-68]' should also be prohibited. + * See __und_svc. + */ + if ((p->ainsn.stack_space < 0) || + (p->ainsn.stack_space > MAX_STACK_SIZE)) + return -EINVAL; + return 0; }