linux-kernel - Re: [PATCH v8 3/5] selftests/sgx: Dump enclave memory map

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Message-ID: <c18409da-dd2b-c813-d7dd-bad81db102bd@linuxfoundation.org>
Date:   Mon, 14 Jun 2021 10:45:43 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     shuah@...nel.org, linux-kselftest@...r.kernel.org,
        linux-sgx@...r.kernel.org,
        Reinette Chatre <reinette.chatre@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH v8 3/5] selftests/sgx: Dump enclave memory map

On 6/11/21 10:27 PM, Jarkko Sakkinen wrote:
> On Fri, Jun 11, 2021 at 04:45:19PM -0600, Shuah Khan wrote:
>> On 6/10/21 2:30 AM, Jarkko Sakkinen wrote:
>>> Often, it's useful to check whether /proc/self/maps looks sane when
>>> dealing with memory mapped objects, especially when they are JIT'ish
>>> dynamically constructed objects. Therefore, dump "/dev/sgx_enclave"
>>> matching lines from the memory map in FIXTURE_SETUP().
>>>
>>> Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
>>> ---
>>>    tools/testing/selftests/sgx/main.c | 14 ++++++++++++++
>>>    1 file changed, 14 insertions(+)
>>>
>>> diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
>>> index 6da19b6bf287..14030f8b85ff 100644
>>> --- a/tools/testing/selftests/sgx/main.c
>>> +++ b/tools/testing/selftests/sgx/main.c
>>> @@ -117,6 +117,8 @@ FIXTURE_SETUP(enclave)
>>>    	Elf64_Sym *sgx_enter_enclave_sym = NULL;
>>>    	struct vdso_symtab symtab;
>>>    	struct encl_segment *seg;
>>> +	char maps_line[256];
>>> +	FILE *maps_file;
>>>    	unsigned int i;
>>>    	void *addr;
>>> @@ -167,6 +169,18 @@ FIXTURE_SETUP(enclave)
>>>    	memset(&self->run, 0, sizeof(self->run));
>>>    	self->run.tcs = self->encl.encl_base;
>>> +	maps_file = fopen("/proc/self/maps", "r");
>>
>> I almost applied these. Does this require root access, if so,
>> please add logic to skip the test if non-root user runs it.
>>
>> Same comments for all other paths that might require root access.
> 
> As Dave stated, it does not. A process can inspect its own state
> through /proc/self path. E.g. Chrome web browser uses /proc/self/exe
> to initialize multiple instances of itself for browser tabs...
> 

Ah yes. I missed the self part. Thanks for clarifying.

> As far as other things go, this patch set does not bind to any other
> new OS resources.
> 

Thank you. I will apply these for 5.14-rc1.

thanks,
-- Shuah