nfsdcld: Before clearing the capability bounding set, check if we have the cap

From: Harald Hoyer <harald@redhat.com>

PR_CAPBSET_DROP can return EINVAL, if an older kernel does support
some capabilities, which are defined by CAP_LAST_CAP, which results in
a failure of the service.

For example kernel 3.4 errors on CAP_EPOLLWAKEUP, which was newly
introduced in 3.5.

So, for future capabilities, we clear until we get an EINVAL for
PR_CAPBSET_READ.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/support/nsm/file.c b/support/nsm/file.c
index 5476446966028528f4d5a0e1a4cf6e1161c335a1..4711c2cd79134f7f1c036c5cda8298aeb53af9a6 100644 (file)
--- a/support/nsm/file.c
+++ b/support/nsm/file.c
@@ -386,7 +386,7 @@ prune_bounding_set(void)
        }
 
        /* prune the bounding set to nothing */
        }
 
        /* prune the bounding set to nothing */

-       for (i = 0; i <= CAP_LAST_CAP; ++i) {
+       for (i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >=0 ; ++i) {

                ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);
                if (ret) {
                        xlog(L_ERROR, "Unable to prune capability %lu from "
                ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);
                if (ret) {
                        xlog(L_ERROR, "Unable to prune capability %lu from "

diff --git a/utils/nfsdcld/nfsdcld.c b/utils/nfsdcld/nfsdcld.c
index e7af4e330c85bcd5e5f2166b3805c67479f1705f..473d069da062666086074130aaa546a624b6ea0d 100644 (file)
--- a/utils/nfsdcld/nfsdcld.c
+++ b/utils/nfsdcld/nfsdcld.c
@@ -102,8 +102,8 @@ cld_set_caps(void)
        }
 
        /* prune the bounding set to nothing */
        }
 
        /* prune the bounding set to nothing */

-       for (i = 0; i <= CAP_LAST_CAP; ++i) {
-               ret = prctl(PR_CAPBSET_DROP, i);
+       for (i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0 ; ++i) {
+               ret = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);

                if (ret) {
                        xlog(L_ERROR, "Unable to prune capability %lu from "
                                      "bounding set: %m", i);
                if (ret) {
                        xlog(L_ERROR, "Unable to prune capability %lu from "
                                      "bounding set: %m", i);