[dpdk-dev] [PATCH v3 1/1] fbarray: get fbarrays from containerized secondary
Burakov, Anatoly
anatoly.burakov at intel.com
Thu Jul 11 15:14:15 CEST 2019
On 11-Jul-19 12:57 PM, Yasufumi Ogawa wrote:
> On 2019/07/11 19:53, Burakov, Anatoly wrote:
>> On 11-Jul-19 11:31 AM, yasufum.o at gmail.com wrote:
>>> From: Yasufumi Ogawa <ogawa.yasufumi at lab.ntt.co.jp>
>>>
>> <...>
>>
>>> + if (getpid() == 1) {
>>> + FILE *hn_fp;
>>> + hn_fp = fopen("/etc/hostname", "r");
>>> + if (hn_fp == NULL) {
>>> + RTE_LOG(ERR, EAL,
>>> + "Cannot open '/etc/hostname' for secondary\n");
>>> + return -1;
>>> + }
>>> +
>>> + /* with docker, /etc/hostname just has one entry of hostname */
>>> + if (fscanf(hn_fp, "%s", proc_id) == EOF) {
>>
>> Apologies for not pointing this out earlier, but do i understand
>> correctly that there's no bounds checking here, and fscanf() will
>> write however many bytes it wants?
> I understand "%s" is not appropriate. hostname is 12 bytes char and I
> thought proc_id[16] is enough, but it is unsafe. In addition, hostname
> can be defined by user with docker's option, so it should be enough for
> user defined name.
>
> How do you think expecting max 32 chars of hostname and set boundary
> "%32s" as following?
>
> proc_id[33]; /* define proc id from hostname less than 33 bytes. */
> ...
> if (fscanf(hn_fp, "%32s", proc_id) == EOF) {
>
As long as it takes NULL-termination into account as well, it should be
OK. I can't recall off the top of my head if %32s includes NULL
terminator (probably not?).
--
Thanks,
Anatoly
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