[libvirt] [PATCHv4 2/2] security: Add a new func use stat to get process DAC label

[lhuang]

On 12/11/2014 05:45 PM, Ján Tomko wrote:
> On 12/09/2014 09:33 AM, Luyao Huang wrote:
>> When use qemuProcessAttach to attach a qemu process, cannot
>> get a right DAC label. Add a new func to get process label
>> via stat func. Do not remove virDomainDefGetSecurityLabelDef
>> before try to use stat to get process DAC label, because
>> There are some other func call virSecurityDACGetProcessLabel.
>>
>> Signed-off-by: Luyao Huang <lhuang at redhat.com>
>> ---
>> v2 add support freeBSD.
>> v3 use snprintf instead of VirAsprintf and move the error
>> settings in virSecurityDACGetProcessLabelInternal.
>> v4 remove errno.h include and thanks Eric advice move this
>> version comment to this place.
>>
>>   src/security/security_dac.c | 84 +++++++++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 81 insertions(+), 3 deletions(-)
>
> ACK and pushed. I reworded the commit message and included the bugzilla link
> and a reference to the other part of the fix that has already been pushed.
Thanks for your help :)
>> diff --git a/src/security/security_dac.c b/src/security/security_dac.c
>> index 85253af..300b245 100644
>> --- a/src/security/security_dac.c
>> +++ b/src/security/security_dac.c
>> @@ -23,6 +23,11 @@
>>   #include <sys/stat.h>
>>   #include <fcntl.h>
>>   
>> +#ifdef  __FreeBSD__
>> +# include <sys/sysctl.h>
>> +# include <sys/user.h>
>> +#endif
>> +
>>   #include "security_dac.h"
>>   #include "virerror.h"
>>   #include "virfile.h"
>> @@ -1236,17 +1241,90 @@ virSecurityDACReserveLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
>>       return 0;
>>   }
>>   
>> +#ifdef __linux__
>> +static int
>> +virSecurityDACGetProcessLabelInternal(pid_t pid,
>> +                                      virSecurityLabelPtr seclabel)
>> +{
>> +    struct stat sb;
>> +    char *path = NULL;
>> +    int ret = -1;
>> +
>> +    VIR_INFO("Getting DAC user and group on process '%d'", pid);
>> +
> VIR_INFO is too noisy for this, I've changed it to VIR_DEBUG.
>> +    if (virAsprintf(&path, "/proc/%d", (int) pid) < 0)
>> +        goto cleanup;
>> +
>> +    if (lstat(path, &sb) < 0) {
>> +        virReportSystemError(errno,
>> +                             _("unable to get PID %d uid and gid via stat"),
>> +                             pid);
>> +        goto cleanup;
>> +    }
>> +
>> +    snprintf(seclabel->label, VIR_SECURITY_LABEL_BUFLEN,
>> +             "+%u:+%u", (unsigned int) sb.st_uid, (unsigned int) sb.st_gid);
>> +    ret = 0;
>> +
>> +cleanup:
>> +    VIR_FREE(path);
>> +    return ret;
>> +}
>> +#elif defined(__FreeBSD__)
>> +static int
>> +virSecurityDACGetProcessLabelInternal(pid_t pid,
>> +                                      virSecurityLabelPtr seclabel)
>> +{
>> +    struct kinfo_proc p;
>> +    int mib[4];
>> +    size_t len = 4;
>> +
>> +    sysctlnametomib("kern.proc.pid", mib, &len);
>> +
>> +    len = sizeof(struct kinfo_proc);
>> +    mib[3] = pid;
>> +
>> +    if (sysctl(mib, 4, &p, &len, NULL, 0) < 0) {
>> +        virReportSystemError(errno,
>> +                             _("unable to get PID %d uid and gid via sysctl"),
>> +                             pid);
>> +        return -1;
>> +    }
>> +
>> +    snprintf(seclabel->label, VIR_SECURITY_LABEL_BUFLEN,
>> +             "+%u:+%u", (unsigned int) p.ki_ruid, (unsigned int) p.ki_rgid);
> This gets the real uid/gid, we want the effective ones like on Linux.
Yes, this should use effective uid/gid after i check the doc.
Thanks for pointing out
>> +
>> +    return 0;
>> +}
>> +#else
>> +static int
>> +virSecurityDACGetProcessLabelInternal(pid_t pid,
>> +                                      virSecurityLabelPtr seclabel)
>> +{
>> +    virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
>> +                   "Cannot get proccess DAC label for pid %d on this platform",
>> +                   (int) pid);
> This fails syntax check - the string needs to be marked for translation with
> _(). I've changed it to virReportSystemError(ENOSYS, ..), to match the use in
> other places.
Oh, it's my fault, thanks.
> Jan
>
Luyao