| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20210719030932.23384-1-huangshaobo6@huawei.com>
Date: Mon, 19 Jul 2021 11:09:32 +0800
From: Shaobo Huang <huangshaobo6@...wei.com>
To: <ardb@...nel.org>
CC: <andreyknvl@...il.com>, <chenzefeng2@...wei.com>,
<dvyukov@...gle.com>, <f.fainelli@...il.com>, <glider@...gle.com>,
<huangshaobo6@...wei.com>, <kasan-dev@...glegroups.com>,
<kepler.chenxin@...wei.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux@...linux.org.uk>,
<liucheng32@...wei.com>, <liuwenliang@...wei.com>,
<nico@...vell.com>, <nixiaoming@...wei.com>, <qbarnes@...il.com>,
<ryabinin.a.a@...il.com>, <sagar.abhishek@...il.com>,
<wuquanming@...wei.com>, <xiaoqian9@...wei.com>,
<young.liuyang@...wei.com>, <zengweilin@...wei.com>
Subject: Re: [PATCH] ARM: fix panic when kasan and kprobe are enabled
On Sat, 17 Jul 2021 at 01:01, Ard Biesheuvel <ardb@...nel.org> wrote:
> On Wed, 14 Jul 2021 at 10:27, Shaobo Huang <huangshaobo6@...wei.com> wrote:
>>
>> From: huangshaobo <huangshaobo6@...wei.com>
>>
>> arm32 uses software to simulate the instruction replaced
>> by kprobe. some instructions may be simulated by constructing
>> assembly functions. therefore, before executing instruction
>> simulation, it is necessary to construct assembly function
>> execution environment in C language through binding registers.
>> after kasan is enabled, the register binding relationship will
>> be destroyed, resulting in instruction simulation errors and
>> causing kernel panic.
>>
>> the kprobe emulate instruction function is distributed in three
>> files: actions-common.c actions-arm.c actions-thumb.c, so disable
>> KASAN when compiling these files.
>>
>> for example, use kprobe insert on cap_capable+20 after kasan
>> enabled, the cap_capable assembly code is as follows:
>> <cap_capable>:
>> e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr}
>> e1a05000 mov r5, r0
>> e280006c add r0, r0, #108 ; 0x6c
>> e1a04001 mov r4, r1
>> e1a06002 mov r6, r2
>> e59fa090 ldr sl, [pc, #144] ;
>> ebfc7bf8 bl c03aa4b4 <__asan_load4>
>> e595706c ldr r7, [r5, #108] ; 0x6c
>> e2859014 add r9, r5, #20
>> ......
>> The emulate_ldr assembly code after enabling kasan is as follows:
>> c06f1384 <emulate_ldr>:
>> e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr}
>> e282803c add r8, r2, #60 ; 0x3c
>> e1a05000 mov r5, r0
>> e7e37855 ubfx r7, r5, #16, #4
>> e1a00008 mov r0, r8
>> e1a09001 mov r9, r1
>> e1a04002 mov r4, r2
>> ebf35462 bl c03c6530 <__asan_load4>
>> e357000f cmp r7, #15
>> e7e36655 ubfx r6, r5, #12, #4
>> e205a00f and sl, r5, #15
>> 0a000001 beq c06f13bc <emulate_ldr+0x38>
>> e0840107 add r0, r4, r7, lsl #2
>> ebf3545c bl c03c6530 <__asan_load4>
>> e084010a add r0, r4, sl, lsl #2
>> ebf3545a bl c03c6530 <__asan_load4>
>> e2890010 add r0, r9, #16
>> ebf35458 bl c03c6530 <__asan_load4>
>> e5990010 ldr r0, [r9, #16]
>> e12fff30 blx r0
>> e356000f cm r6, #15
>> 1a000014 bne c06f1430 <emulate_ldr+0xac>
>> e1a06000 mov r6, r0
>> e2840040 add r0, r4, #64 ; 0x40
>> ......
>>
>> when running in emulate_ldr to simulate the ldr instruction, panic
>> occurred, and the log is as follows:
>> Unable to handle kernel NULL pointer dereference at virtual address
>> 00000090
>> pgd = ecb46400
>> [00000090] *pgd=2e0fa003, *pmd=00000000
>> Internal error: Oops: 206 [#1] SMP ARM
>> PC is at cap_capable+0x14/0xb0
>> LR is at emulate_ldr+0x50/0xc0
>> psr: 600d0293 sp : ecd63af8 ip : 00000004 fp : c0a7c30c
>> r10: 00000000 r9 : c30897f4 r8 : ecd63cd4
>> r7 : 0000000f r6 : 0000000a r5 : e59fa090 r4 : ecd63c98
>> r3 : c06ae294 r2 : 00000000 r1 : b7611300 r0 : bf4ec008
>> Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user
>> Control: 32c5387d Table: 2d546400 DAC: 55555555
>> Process bash (pid: 1643, stack limit = 0xecd60190)
>> (cap_capable) from (kprobe_handler+0x218/0x340)
>> (kprobe_handler) from (kprobe_trap_handler+0x24/0x48)
>> (kprobe_trap_handler) from (do_undefinstr+0x13c/0x364)
>> (do_undefinstr) from (__und_svc_finish+0x0/0x30)
>> (__und_svc_finish) from (cap_capable+0x18/0xb0)
>> (cap_capable) from (cap_vm_enough_memory+0x38/0x48)
>> (cap_vm_enough_memory) from
>> (security_vm_enough_memory_mm+0x48/0x6c)
>> (security_vm_enough_memory_mm) from
>> (copy_process.constprop.5+0x16b4/0x25c8)
>> (copy_process.constprop.5) from (_do_fork+0xe8/0x55c)
>> (_do_fork) from (SyS_clone+0x1c/0x24)
>> (SyS_clone) from (__sys_trace_return+0x0/0x10)
>> Code: 0050a0e1 6c0080e2 0140a0e1 0260a0e1 (f801f0e7)
>>
>> Fixes: 35aa1df43283 ("ARM kprobes: instruction single-stepping support")
>> Fixes: 421015713b30 ("ARM: 9017/2: Enable KASan for ARM")
>> Signed-off-by: huangshaobo <huangshaobo6@...wei.com>
>> Asked-by: Ard Biesheuvel <ardb@...nel.org>
>
> Please don't do this - the maintainer will pick it up when applying,
> or when you send a new version of the patch, it is OK to add these
> tags if you have not made any substantial changes.
>
> But please do *not* add tags like this on someone else's behalf by
> replying to the email - and I should also point out that 'asked-by' is
> bogus.
>
Hi ardb,
1.The original patch you have been asked-by by email before, link: https://lore.kernel.org/linux-arm-kernel/CAMj1kXGqfF68MT4WwrxS0cYiUBb0gODDh-wGZSQcW9vxdfK90A@mail.gmail.com/
2.In addition to adding the asked-by tag, there is no other content modification in this patch
3.The patch was reissued because the previous recipient did not include kasan maintainer and reviewers
thanks,
ShaoBo Huang
>
>> ---
>> arch/arm/probes/kprobes/Makefile | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/arm/probes/kprobes/Makefile b/arch/arm/probes/kprobes/Makefile
>> index 14db56f49f0a..6159010dac4a 100644
>> --- a/arch/arm/probes/kprobes/Makefile
>> +++ b/arch/arm/probes/kprobes/Makefile
>> @@ -1,4 +1,7 @@
>> # SPDX-License-Identifier: GPL-2.0
>> +KASAN_SANITIZE_actions-common.o := n
>> +KASAN_SANITIZE_actions-arm.o := n
>> +KASAN_SANITIZE_actions-thumb.o := n
>> obj-$(CONFIG_KPROBES) += core.o actions-common.o checkers-common.o
>> obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o
>> test-kprobes-objs := test-core.o
>> --
>> 2.12.3
>>
Powered by blists - more mailing lists