From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF419C43381 for ; Wed, 6 Mar 2019 13:14:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58CF620661 for ; Wed, 6 Mar 2019 13:14:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="iaP2C3LD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbfCFNOA (ORCPT ); Wed, 6 Mar 2019 08:14:00 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:41270 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728169AbfCFNN7 (ORCPT ); Wed, 6 Mar 2019 08:13:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=fb1EgBA4VJ90/W8naKhWowLwPdlXsolvIuUw/+KUcq4=; b=iaP2C3LDBGlXZoRhKQb4/qSGn f0wUP/jOH8xu3ywQ5/nZIvaccXEQyze4CJ5rQY9jaRQbc+jSyOm5jdIyI1U0PitkeC2Uh7tiTR4qT AYprlDqYR29LjNAFuh+BvVQeyugA5Sg6sea44Yv9ZN0WhgjryEc/St9h4k4ot21P8s9j4crF2bf8U ajO+ydjJ1fSeHipQfFos4iTmtGZ+fnF32IqykBc74vJtGplXoPm56yrukXEB7nAq0bd7RbJjlFXTm ClMBqvLruzAFaHAmaaTdj/CzRlKWCtFH0UrYGnadpTVZkJTkkFySiYCtbO+nwNVVzQtkOz3bjEG2G Msp2miG4Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h1WMm-0008Rf-Ml; Wed, 06 Mar 2019 13:13:49 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 1019A20288BA6; Wed, 6 Mar 2019 14:13:47 +0100 (CET) Date: Wed, 6 Mar 2019 14:13:47 +0100 From: Peter Zijlstra To: Dmitry Vyukov Cc: Linus Torvalds , Thomas Gleixner , "H. Peter Anvin" , Julien Thierry , Will Deacon , Andy Lutomirski , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andy Lutomirski , Borislav Petkov , Denys Vlasenko , LKML , Andrey Ryabinin Subject: Re: [PATCH 1/8] kasan,x86: Frob kasan_report() in an exception Message-ID: <20190306131347.GX32534@hirez.programming.kicks-ass.net> References: <20190228145450.289603901@infradead.org> <20190228150152.078767622@infradead.org> <20190301144556.GY32477@hirez.programming.kicks-ass.net> <20190301152305.GJ32494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190301152305.GJ32494@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 01, 2019 at 04:23:05PM +0100, Peter Zijlstra wrote: > But yes, I'll try some annotation, see what that looks like. OK; that took a lot of time.. and a number of objtool bugs fixed but I think I have something that I don't hate -- although it is not as solid as I'd like it to be. unmodified: 0000 0000000000000150 <__asan_load1>: 0000 150: 48 b8 ff ff ff ff ff movabs $0xffff7fffffffffff,%rax 0007 157: 7f ff ff 000a 15a: 48 8b 0c 24 mov (%rsp),%rcx 000e 15e: 48 39 c7 cmp %rax,%rdi 0011 161: 76 23 jbe 186 <__asan_load1+0x36> 0013 163: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 001a 16a: fc ff df 001d 16d: 48 89 fa mov %rdi,%rdx 0020 170: 48 c1 ea 03 shr $0x3,%rdx 0024 174: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 0028 178: 84 c0 test %al,%al 002a 17a: 75 01 jne 17d <__asan_load1+0x2d> 002c 17c: c3 retq 002d 17d: 89 fa mov %edi,%edx 002f 17f: 83 e2 07 and $0x7,%edx 0032 182: 38 d0 cmp %dl,%al 0034 184: 7f f6 jg 17c <__asan_load1+0x2c> 0036 186: 31 d2 xor %edx,%edx 0038 188: be 01 00 00 00 mov $0x1,%esi 003d 18d: e9 00 00 00 00 jmpq 192 <__asan_load1+0x42> 003e 18e: R_X86_64_PLT32 kasan_report-0x4 exception: 0000 0000000000000150 <__asan_load1>: 0000 150: 48 b8 ff ff ff ff ff movabs $0xffff7fffffffffff,%rax 0007 157: 7f ff ff 000a 15a: 48 8b 0c 24 mov (%rsp),%rcx 000e 15e: 48 39 c7 cmp %rax,%rdi 0011 161: 76 23 jbe 186 <__asan_load1+0x36> 0013 163: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 001a 16a: fc ff df 001d 16d: 48 89 fa mov %rdi,%rdx 0020 170: 48 c1 ea 03 shr $0x3,%rdx 0024 174: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 0028 178: 84 c0 test %al,%al 002a 17a: 75 01 jne 17d <__asan_load1+0x2d> 002c 17c: c3 retq 002d 17d: 89 fa mov %edi,%edx 002f 17f: 83 e2 07 and $0x7,%edx 0032 182: 38 d0 cmp %dl,%al 0034 184: 7f f6 jg 17c <__asan_load1+0x2c> 0036 186: 65 48 8b 04 25 00 00 mov %gs:0x0,%rax 003d 18d: 00 00 003b 18b: R_X86_64_32S current_task 003f 18f: 8b 80 68 08 00 00 mov 0x868(%rax),%eax 0045 195: 85 c0 test %eax,%eax 0047 197: 75 e3 jne 17c <__asan_load1+0x2c> 0049 199: be 01 00 00 00 mov $0x1,%esi 004e 19e: 31 d2 xor %edx,%edx 0050 1a0: 0f 0b ud2 0052 1a2: c3 retq annotated: 0000 0000000000000150 <__asan_load1>: 0000 150: 48 b8 ff ff ff ff ff movabs $0xffff7fffffffffff,%rax 0007 157: 7f ff ff 000a 15a: 53 push %rbx 000b 15b: 48 8b 4c 24 08 mov 0x8(%rsp),%rcx 0010 160: 48 39 c7 cmp %rax,%rdi 0013 163: 76 24 jbe 189 <__asan_load1+0x39> 0015 165: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 001c 16c: fc ff df 001f 16f: 48 89 fa mov %rdi,%rdx 0022 172: 48 c1 ea 03 shr $0x3,%rdx 0026 176: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 002a 17a: 84 c0 test %al,%al 002c 17c: 75 02 jne 180 <__asan_load1+0x30> 002e 17e: 5b pop %rbx 002f 17f: c3 retq 0030 180: 89 fa mov %edi,%edx 0032 182: 83 e2 07 and $0x7,%edx 0035 185: 38 d0 cmp %dl,%al 0037 187: 7f f5 jg 17e <__asan_load1+0x2e> 0039 189: 9c pushfq 003a 18a: 5b pop %rbx 003b 18b: 90 nop 003c 18c: 90 nop 003d 18d: 90 nop 003e 18e: 31 d2 xor %edx,%edx 0040 190: be 01 00 00 00 mov $0x1,%esi 0045 195: e8 00 00 00 00 callq 19a <__asan_load1+0x4a> 0046 196: R_X86_64_PLT32 __kasan_report-0x4 004a 19a: 53 push %rbx 004b 19b: 9d popfq 004c 19c: 5b pop %rbx 004d 19d: c3 retq --- --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -28,6 +28,23 @@ #ifdef CONFIG_KASAN void __init kasan_early_init(void); void __init kasan_init(void); + +#include + +extern void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip); + +static __always_inline +void kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) +{ + unsigned long flags; + + flags = smap_save(); + __kasan_report(addr, size, is_write, ip); + smap_restore(flags); + +} +#define kasan_report kasan_report + #else static inline void kasan_early_init(void) { } static inline void kasan_init(void) { } --- a/arch/x86/include/asm/smap.h +++ b/arch/x86/include/asm/smap.h @@ -46,6 +46,8 @@ #ifdef CONFIG_X86_SMAP +#include + static __always_inline void clac(void) { /* Note: a barrier is implicit in alternative() */ @@ -58,6 +60,18 @@ static __always_inline void stac(void) alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP); } +static __always_inline unsigned long smap_save(void) +{ + unsigned long flags = arch_local_save_flags(); + clac(); + return flags; +} + +static __always_inline void smap_restore(unsigned long flags) +{ + arch_local_irq_restore(flags); +} + /* These macros can be used in asm() statements */ #define ASM_CLAC \ ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP) @@ -69,6 +83,9 @@ static __always_inline void stac(void) static inline void clac(void) { } static inline void stac(void) { } +static inline unsigned long smap_save(void) { return 0; } +static inline void smap_restore(unsigned long flags) { } + #define ASM_CLAC #define ASM_STAC --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -83,6 +83,8 @@ size_t kasan_metadata_size(struct kmem_c bool kasan_save_enable_multi_shot(void); void kasan_restore_multi_shot(bool enabled); +void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip); + #else /* CONFIG_KASAN */ static inline void kasan_unpoison_shadow(const void *address, size_t size) {} @@ -153,8 +155,14 @@ static inline void kasan_remove_zero_sha static inline void kasan_unpoison_slab(const void *ptr) { } static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; } +static inline void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) { } + #endif /* CONFIG_KASAN */ +#ifndef kasan_report +#define kasan_report(addr, size, is_write, ip) __kasan_report(addr, size, is_write, ip) +#endif + #ifdef CONFIG_KASAN_GENERIC #define KASAN_SHADOW_INIT 0 @@ -177,9 +185,6 @@ 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) { } --- a/mm/kasan/generic_report.c +++ b/mm/kasan/generic_report.c @@ -118,14 +118,14 @@ const char *get_bug_type(struct kasan_ac #define DEFINE_ASAN_REPORT_LOAD(size) \ void __asan_report_load##size##_noabort(unsigned long addr) \ { \ - kasan_report(addr, size, false, _RET_IP_); \ + __kasan_report(addr, size, false, _RET_IP_); \ } \ EXPORT_SYMBOL(__asan_report_load##size##_noabort) #define DEFINE_ASAN_REPORT_STORE(size) \ void __asan_report_store##size##_noabort(unsigned long addr) \ { \ - kasan_report(addr, size, true, _RET_IP_); \ + __kasan_report(addr, size, true, _RET_IP_); \ } \ EXPORT_SYMBOL(__asan_report_store##size##_noabort) @@ -142,12 +142,12 @@ DEFINE_ASAN_REPORT_STORE(16); void __asan_report_load_n_noabort(unsigned long addr, size_t size) { - kasan_report(addr, size, false, _RET_IP_); + __kasan_report(addr, size, false, _RET_IP_); } EXPORT_SYMBOL(__asan_report_load_n_noabort); void __asan_report_store_n_noabort(unsigned long addr, size_t size) { - kasan_report(addr, size, true, _RET_IP_); + __kasan_report(addr, size, true, _RET_IP_); } EXPORT_SYMBOL(__asan_report_store_n_noabort); --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -130,8 +130,6 @@ void check_memory_region(unsigned long a void *find_first_bad_addr(void *addr, size_t size); const char *get_bug_type(struct kasan_access_info *info); -void kasan_report(unsigned long addr, size_t size, - bool is_write, unsigned long ip); void kasan_report_invalid_free(void *object, unsigned long ip); #if defined(CONFIG_KASAN_GENERIC) && \ --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -281,7 +281,7 @@ void kasan_report_invalid_free(void *obj end_report(&flags); } -void kasan_report(unsigned long addr, size_t size, +void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip) { struct kasan_access_info info; --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -43,6 +43,7 @@ enum op_dest_type { OP_DEST_REG_INDIRECT, OP_DEST_MEM, OP_DEST_PUSH, + OP_DEST_PUSHF, OP_DEST_LEAVE, }; @@ -57,6 +58,7 @@ enum op_src_type { OP_SRC_REG_INDIRECT, OP_SRC_CONST, OP_SRC_POP, + OP_SRC_POPF, OP_SRC_ADD, OP_SRC_AND, }; --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -357,13 +357,13 @@ int arch_decode_instruction(struct elf * /* pushf */ *type = INSN_STACK; op->src.type = OP_SRC_CONST; - op->dest.type = OP_DEST_PUSH; + op->dest.type = OP_DEST_PUSHF; break; case 0x9d: /* popf */ *type = INSN_STACK; - op->src.type = OP_SRC_POP; + op->src.type = OP_SRC_POPF; op->dest.type = OP_DEST_MEM; break; --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1359,11 +1359,11 @@ static int update_insn_state_regs(struct return 0; /* push */ - if (op->dest.type == OP_DEST_PUSH) + if (op->dest.type == OP_DEST_PUSH || op->dest.type == OP_DEST_PUSHF) cfa->offset += 8; /* pop */ - if (op->src.type == OP_SRC_POP) + if (op->src.type == OP_SRC_POP || op->src.type == OP_SRC_POPF) cfa->offset -= 8; /* add immediate to sp */ @@ -1620,6 +1620,7 @@ static int update_insn_state(struct inst break; case OP_SRC_POP: + case OP_SRC_POPF: if (!state->drap && op->dest.type == OP_DEST_REG && op->dest.reg == cfa->base) { @@ -1684,6 +1685,7 @@ static int update_insn_state(struct inst break; case OP_DEST_PUSH: + case OP_DEST_PUSHF: state->stack_size += 8; if (cfa->base == CFI_SP) cfa->offset += 8; @@ -1774,7 +1776,7 @@ static int update_insn_state(struct inst break; case OP_DEST_MEM: - if (op->src.type != OP_SRC_POP) { + if (op->src.type != OP_SRC_POP && op->src.type != OP_SRC_POPF) { WARN_FUNC("unknown stack-related memory operation", insn->sec, insn->offset); return -1; @@ -2071,6 +2073,16 @@ static int validate_branch(struct objtoo if (update_insn_state(insn, &state)) return 1; + if (insn->stack_op.dest.type == OP_DEST_PUSHF) { + if (state.uaccess) + state.uaccess_stack++; + } + + if (insn->stack_op.src.type == OP_SRC_POPF) { + if (state.uaccess_stack && !--state.uaccess_stack) + state.uaccess = func_uaccess_safe(func); + } + break; case INSN_STAC: @@ -2088,7 +2100,7 @@ static int validate_branch(struct objtoo return 1; } - if (func_uaccess_safe(func)) { + if (func_uaccess_safe(func) && !state.uaccess_stack) { WARN_FUNC("UACCESS-safe disables UACCESS", sec, insn->offset); return 1; } --- a/tools/objtool/check.h +++ b/tools/objtool/check.h @@ -32,6 +32,7 @@ struct insn_state { unsigned char type; bool bp_scratch; bool drap, end, uaccess; + int uaccess_stack; int drap_reg, drap_offset; struct cfi_reg vals[CFI_NUM_REGS]; };