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

[Ján Tomko]

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.

> 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.

> +
> +    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.

Jan

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