[LTP] [PATCH v2 2/2] Add shmat04 SysV IPC bug reproducer

[Andrea Cervesato]

Hi!

On 2/26/24 17:06, Cyril Hrubis wrote:
> Hi!
>> +static void change_access(void *addr, int size, int prot)
>> +{
>> +	switch (prot) {
>> +	case PROT_NONE:
>> +		tst_res(TINFO, "Disable memory access. addr: %p - size: %d",
>> +			addr, size);
>> +		break;
>> +	case PROT_WRITE:
>> +		tst_res(TINFO, "Enable write memory access. addr: %p - size: %d",
>> +			addr, size);
>> +		break;
>> +	default:
>> +		tst_res(TINFO, "Change memory access. addr: %p - size: %d",
>> +			addr, size);
>> +		break;
>> +	}
>> +
>> +	SAFE_MPROTECT(addr, size, prot);
>> +}
> Hmm, it's kind of ugly how we wrap the macro here like that...
>
> What about we instead add debugging messages to all the SAFE_MACROS()?
>
> Given that we added TDEBUG flag recently we can do soemthing as:
>
> 	tst_res_(TDEBUG, file, lineno, "mprotect(%p, %d, %s)",
> 	         addr, size, prot_to_str(prot));
>
> To the SAFE_MPROTECT() and get the verbose output for free with verbose
> flag passed to the test.
>
> We can do that with all SAFE_MACROS() then we do not have to print most
> of the messages in this test...
Is this comment related with the previous patch of the set?
>> +
>> +static void run(void)
>> +{
>> +	struct shmid_ds shmid_ds;
>> +	void *sh_mem;
>> +
>> +	segment_id = SAFE_SHMGET(
>> +		key_id,
>> +		segment_size,
>> +		IPC_CREAT | IPC_EXCL | 0600);
>> +
>> +	sh_mem = SAFE_SHMAT(segment_id, NULL, 0);
>> +
>> +	tst_res(TINFO, "Attached at %p. key: %d - size: %lu",
>> +		sh_mem, segment_id, segment_size);
>> +
>> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
>> +
>> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
>> +
>> +	change_access(sh_mem + page_size, page_size, PROT_NONE);
>> +	change_access(sh_mem, 2 * page_size, PROT_WRITE);
>> +
>> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
>> +
>> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
>> +	tst_res(TINFO, "Delete attached memory");
>> +
>> +	SAFE_SHMDT(sh_mem);
>> +	SAFE_SHMCTL(segment_id, IPC_STAT, &shmid_ds);
>> +
>> +	tst_res(TINFO, "Number of attaches: %lu", shmid_ds.shm_nattch);
>> +
>> +	SAFE_SHMCTL(segment_id, IPC_RMID, NULL);
>> +	segment_id = -1;
>> +
>> +	if (shmid_ds.shm_nattch)
>> +		tst_res(TFAIL, "The system is affected by the SysV IPC bug");
>> +	else
>> +		tst_res(TPASS, "Test passed");
> These messages are not really that useful, we can as well do:
>
> TST_EXP_EQ_LU(shmid_ds.shm_nattach, 0);
>
> That will provide better message than "PASS: Test passed"
>
>> +}
>> +
>> +static void setup(void)
>> +{
>> +	key_id = GETIPCKEY();
>> +	page_size = getpagesize();
>> +
>> +	tst_res(TINFO, "Key id: %d", key_id);
>> +	tst_res(TINFO, "Page size: %d", page_size);
>> +
>> +	segment_size = 3 * page_size;
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> +	if (segment_id != -1)
>> +		SAFE_SHMCTL(segment_id, IPC_RMID, NULL);
>> +}
>> +
>> +static struct tst_test test = {
>> +	.test_all = run,
>> +	.setup = setup,
>> +	.cleanup = cleanup,
>> +};
>> -- 
>> 2.35.3
>>
>>
>> -- 
>> Mailing list info: https://lists.linux.it/listinfo/ltp

Andrea