Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754143AbaLHGcO (ORCPT ); Mon, 8 Dec 2014 01:32:14 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:12550 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754122AbaLHGcM (ORCPT ); Mon, 8 Dec 2014 01:32:12 -0500 From: Wang Nan To: , , CC: , , Subject: [PATCH v14 4/7] ARM: kprobes: disallow probing stack consuming instructions Date: Mon, 8 Dec 2014 14:28:23 +0800 Message-ID: <1418020103-69212-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1418020040-68977-1-git-send-email-wangnan0@huawei.com> References: <1418020040-68977-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch prohibits probing instructions for which the stack requirements are unable to be determined statically. Some test cases are found not work again after the modification, this patch also removes them. Signed-off-by: Wang Nan Reviewed-by: Jon Medhurst --- v1 -> v2: - Use MAX_STACK_SIZE macro instead of hard coded stack size. v2 -> v3: - Commit message improvements. v3 -> v4: - Commit message improvements. v4 -> v5: - Move to arch/arm/probes. --- arch/arm/include/asm/kprobes.h | 1 - arch/arm/include/asm/probes.h | 12 ++++++++++++ arch/arm/kernel/entry-armv.S | 3 ++- arch/arm/probes/kprobes/core.c | 9 +++++++++ arch/arm/probes/kprobes/test-arm.c | 16 ++++++++++------ 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/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 74f3dc3..3a58db4 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.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; } diff --git a/arch/arm/probes/kprobes/test-arm.c b/arch/arm/probes/kprobes/test-arm.c index d9a1255..fdeb300 100644 --- a/arch/arm/probes/kprobes/test-arm.c +++ b/arch/arm/probes/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,"]") -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/