Re: [PATCH 4/5] tools/dm_depriv: Add first cut RLIMITs

[George Dunlap <george.dunlap@citrix.com>]

On 10/26/2018 03:02 PM, Ian Jackson wrote:
> George Dunlap writes ("[PATCH 4/5] tools/dm_depriv: Add first cut RLIMITs"):
>> Limit the ability of a potentially compromised QEMU to consume system
>> resources.  Key limits:
>>  - RLIMIT_FSIZE (file size): 256KiB
>>  - RLIMIT_NPROC (after uid changes to a unique uid)
> 
> Thanks.
> 
>> +static struct {
>> +    int resource;
>> +    rlim_t limit;
>> +} rlimits[] = {
>> +#define RLIMIT_ENTRY(r, l) \
>> +    { .resource = r, .limit = l }
>> +    /* Big enough for log files, not big enough for a DoS */
>> +    RLIMIT_ENTRY(RLIMIT_FSIZE, 256*1024),
>> +
>> +    /* Shouldn't need any of these */
>> +    RLIMIT_ENTRY(RLIMIT_NPROC, 0),
>> +    RLIMIT_ENTRY(RLIMIT_CORE, 0),
>> +    RLIMIT_ENTRY(RLIMIT_MSGQUEUE, 0),
>> +    RLIMIT_ENTRY(RLIMIT_LOCKS, 0),
>> +    RLIMIT_ENTRY(RLIMIT_MEMLOCK, 0),
> 
> I would have justified the values so this looked more tabular.

Sure.

> 
>> +    /* Set various "easy" rlimits */
>> +    for (i = 0; rlimits[i].resource != RLIMIT_NLIMITS; i++) {
>> +        struct rlimit rlim;
>> +
>> +        rlim.rlim_cur = rlim.rlim_max = rlimits[i].limit;
>> +        
>> +        r = setrlimit(rlimits[i].resource, &rlim);
>> +        if (r < 0) {
>> +            LOGE(ERROR, "Setting rlimit %d to %lld failed\n",
>> +                                  rlimits[i].resource,
>> +                                  (unsigned long long)rlimits[i].limit);
> 
> I think you mean %llu not %lld.  With that last point changed,
> 
> Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

Thanks.

 -George

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