Re: [PATCH] coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()

From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>
Cc: coresight@lists.linaro.org, Stephen Boyd <swboyd@chromium.org>,
	Denis Nikitin <denik@chromium.org>,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org
Subject: Re: [PATCH] coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()
Date: Tue, 25 May 2021 09:54:57 +0100	[thread overview]
Message-ID: <dc18845a-73bf-9cbf-6749-6271dcaac9e8@arm.com> (raw)
In-Reply-To: <8e0dbf24-af71-9bce-b615-ce7b1d12a720@arm.com>

Hi Sai

On 05/05/2021 10:47, Suzuki K Poulose wrote:
> On 05/05/2021 10:34, Sai Prakash Ranjan wrote:
>> commit 6f755e85c332 ("coresight: Add helper for inserting synchronization
>> packets") removed trailing '\0' from barrier_pkt array and updated the
>> call sites like etb_update_buffer() to have proper checks for barrier_pkt
>> size before read but missed updating tmc_update_etf_buffer() which still
>> reads barrier_pkt past the array size resulting in KASAN out-of-bounds
>> bug. Fix this by adding a check for barrier_pkt size before accessing
>> like it is done in etb_update_buffer().
>>
>>   BUG: KASAN: global-out-of-bounds in tmc_update_etf_buffer+0x4b8/0x698
>>   Read of size 4 at addr ffffffd05b7d1030 by task perf/2629
>>
>>   Call trace:
>>    dump_backtrace+0x0/0x27c
>>    show_stack+0x20/0x2c
>>    dump_stack+0x11c/0x188
>>    print_address_description+0x3c/0x4a4
>>    __kasan_report+0x140/0x164
>>    kasan_report+0x10/0x18
>>    __asan_report_load4_noabort+0x1c/0x24
>>    tmc_update_etf_buffer+0x4b8/0x698
>>    etm_event_stop+0x248/0x2d8
>>    etm_event_del+0x20/0x2c
>>    event_sched_out+0x214/0x6f0
>>    group_sched_out+0xd0/0x270
>>    ctx_sched_out+0x2ec/0x518
>>    __perf_event_task_sched_out+0x4fc/0xe6c
>>    __schedule+0x1094/0x16a0
>>    preempt_schedule_irq+0x88/0x170
>>    arm64_preempt_schedule_irq+0xf0/0x18c
>>    el1_irq+0xe8/0x180
>>    perf_event_exec+0x4d8/0x56c
>>    setup_new_exec+0x204/0x400
>>    load_elf_binary+0x72c/0x18c0
>>    search_binary_handler+0x13c/0x420
>>    load_script+0x500/0x6c4
>>    search_binary_handler+0x13c/0x420
>>    exec_binprm+0x118/0x654
>>    __do_execve_file+0x77c/0xba4
>>    __arm64_compat_sys_execve+0x98/0xac
>>    el0_svc_common+0x1f8/0x5e0
>>    el0_svc_compat_handler+0x84/0xb0
>>    el0_svc_compat+0x10/0x50
>>
>>   The buggy address belongs to the variable:
>>    barrier_pkt+0x10/0x40
>>
>>   Memory state around the buggy address:
>>    ffffffd05b7d0f00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
>>    ffffffd05b7d0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>   >ffffffd05b7d1000: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 03
>>                                        ^
>>    ffffffd05b7d1080: fa fa fa fa 00 02 fa fa fa fa fa fa 03 fa fa fa
>>    ffffffd05b7d1100: fa fa fa fa 00 00 00 00 05 fa fa fa fa fa fa fa
>>   ==================================================================
>>
>> Fixes: 6f755e85c332 ("coresight: Add helper for inserting 
>> synchronization packets")

I have changed the commit to :

Fixes: 0c3fc4d5fa26 ("coresight: Add barrier packet for synchronisation")

Applied.

Thanks
Suzuki