[dpdk-dev] [PATCH v3 1/1] fbarray: get fbarrays from containerized secondary

[Yasufumi Ogawa]

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) {

Thanks,
Yasufumi