[libvirt] [PATCH 1/5] util: simplify virSetUIDGIDWithCaps
The need_prctl variable is not really needed. If it is false,
capng_apply will be called twice with the same set, causing
a little extra work but no problem. This keeps the code a bit
simpler.
It is also clearer to invoke capng_apply(CAPNG_SELECT_BOUNDS)
separately, to make sure it is done while we have CAP_SETPCAP.
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
---
src/util/virutil.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/src/util/virutil.c b/src/util/virutil.c
index 42b4295..36e6cee 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -3003,7 +3003,7 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid, unsigned long long
capBits,
{
int ii, capng_ret, ret = -1;
bool need_setgid = false, need_setuid = false;
- bool need_prctl = false, need_setpcap = false;
+ bool need_setpcap = false;
/* First drop all caps (unless the requested uid is "unchanged" or
* root and clearExistingCaps wasn't requested), then add back
@@ -3043,17 +3043,15 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid, unsigned long long
capBits,
capng_update(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED, CAP_SETPCAP);
# endif
- need_prctl = capBits || need_setgid || need_setuid || need_setpcap;
-
/* Tell system we want to keep caps across uid change */
- if (need_prctl && prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0)) {
+ if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0)) {
virReportSystemError(errno, "%s",
_("prctl failed to set KEEPCAPS"));
goto cleanup;
}
/* Change to the temp capabilities */
- if ((capng_ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
+ if ((capng_ret = capng_apply(CAPNG_SELECT_CAPS)) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("cannot apply process capabilities %d"), capng_ret);
goto cleanup;
@@ -3063,12 +3061,18 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid, unsigned long long
capBits,
goto cleanup;
/* Tell it we are done keeping capabilities */
- if (need_prctl && prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0)) {
+ if (prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0)) {
virReportSystemError(errno, "%s",
_("prctl failed to reset KEEPCAPS"));
goto cleanup;
}
+ /* Set bounding set while we have CAP_SETPCAP. Unfortunately we cannot
+ * do this if we failed to get the capability above, so ignore the
+ * return value.
+ */
+ capng_apply(CAPNG_SELECT_BOUNDS);
+
/* Drop the caps that allow setuid/gid (unless they were requested) */
if (need_setgid)
capng_update(CAPNG_DROP, CAPNG_EFFECTIVE|CAPNG_PERMITTED, CAP_SETGID);
@@ -3078,7 +3082,7 @@ virSetUIDGIDWithCaps(uid_t uid, gid_t gid, unsigned long long
capBits,
if (need_setpcap)
capng_update(CAPNG_DROP, CAPNG_EFFECTIVE|CAPNG_PERMITTED, CAP_SETPCAP);
- if (need_prctl && ((capng_ret = capng_apply(CAPNG_SELECT_BOTH)) < 0)) {
+ if (((capng_ret = capng_apply(CAPNG_SELECT_CAPS)) < 0)) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("cannot apply process capabilities %d"), capng_ret);
ret = -1;
--
1.8.1.4