selftests: capabilities: namespace create varies for root and normal user

This patchset fixes TODO:
"If we're already root, we could skip creating the userns."

Change namespace creation for root and non-root
user differently in create_and_enter_ns() function
in this file:
tools/testing/selftests/capabilities/test_execve.c

Test result with root user:
$sudo make  TARGETS="capabilities" kselftest
 ...
 TAP version 13
 1..1
 timeout set to 45
 selftests: capabilities: test_execve
 TAP version 13
 1..12
 [RUN]       +++ Tests with uid == 0 +++
 [NOTE]      Using global UIDs for tests
 [RUN]       Root => ep
 ...
 ok 12 Passed
 Totals: pass:12 fail:0 xfail:0 xpass:0 skip:0 error:0
 ==================================================
 TAP version 13
 1..9
 [RUN]       +++ Tests with uid != 0 +++
 [NOTE]      Using global UIDs for tests
 [RUN]       Non-root => no caps
 ...
 ok 9 Passed
 Totals: pass:9 fail:0 xfail:0 xpass:0 skip:0 error:0

Test result without root or normal user:
$make  TARGETS="capabilities" kselftest
 ...
 timeout set to 45
 selftests: capabilities: test_execve
 TAP version 13
 1..12
 [RUN]       +++ Tests with uid == 0 +++
 [NOTE]      Using a user namespace for tests
 [RUN]       Root => ep
 validate_cap:: Capabilities after execve were correct
 ok 1 Passed
 Check cap_ambient manipulation rules
 ok 2 PR_CAP_AMBIENT_RAISE failed on non-inheritable cap
 ok 3 PR_CAP_AMBIENT_RAISE failed on non-permitted cap
 ok 4 PR_CAP_AMBIENT_RAISE worked
 ok 5 Basic manipulation appears to work
 [RUN]       Root +i => eip
 validate_cap:: Capabilities after execve were correct
 ok 6 Passed
 [RUN]       UID 0 +ia => eipa
 validate_cap:: Capabilities after execve were correct
 ok 7 Passed
 ok 8 # SKIP SUID/SGID tests (needs privilege)
 Planned tests != run tests (12 != 8)
 Totals: pass:7 fail:0 xfail:0 xpass:0 skip:1 error:0
 ==================================================
 TAP version 13
 1..9
 [RUN]       +++ Tests with uid != 0 +++
 [NOTE]      Using a user namespace for tests
 [RUN]       Non-root => no caps
 validate_cap:: Capabilities after execve were correct
 ok 1 Passed
 Check cap_ambient manipulation rules
 ok 2 PR_CAP_AMBIENT_RAISE failed on non-inheritable cap
 ok 3 PR_CAP_AMBIENT_RAISE failed on non-permitted cap
 ok 4 PR_CAP_AMBIENT_RAISE worked
 ok 5 Basic manipulation appears to work
 [RUN]       Non-root +i => i
 validate_cap:: Capabilities after execve were correct
 ok 6 Passed
 [RUN]       UID 1 +ia => eipa
 validate_cap:: Capabilities after execve were correct
 ok 7 Passed
 ok 8 # SKIP SUID/SGID tests (needs privilege)
 Planned tests != run tests (9 != 8)
 Totals: pass:7 fail:0 xfail:0 xpass:0 skip:1 error:0

Signed-off-by: Swarup Laxman Kotiaklapudi <swarupkotikalapudi@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 1 insertions, 5 deletions

diff --git a/tools/testing/selftests/capabilities/test_execve.c b/tools/testing/selftests/capabilities/test_execve.c
index e3a352b020a7..7cde07a5df78 100644
--- a/tools/testing/selftests/capabilities/test_execve.c
+++ b/tools/testing/selftests/capabilities/test_execve.c
@@ -88,11 +88,7 @@ static bool create_and_enter_ns(uid_t inner_uid)
 	outer_uid = getuid();
 	outer_gid = getgid();
 
-	/*
-	 * TODO: If we're already root, we could skip creating the userns.
-	 */
-
-	if (unshare(CLONE_NEWNS) == 0) {
+	if (outer_uid == 0 && unshare(CLONE_NEWNS) == 0) {
 		ksft_print_msg("[NOTE]\tUsing global UIDs for tests\n");
 		if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
 			ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n",