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

  Change namespace creation for root and non-root
user differently in create_and_enter_ns() function

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>
---
 tools/testing/selftests/capabilities/test_execve.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
  

esOn Fri, Sep 29, 2023 at 06:23:48PM +0530, Swarup Laxman Kotiaklapudi wrote:
> Change namespace creation for root and non-root
> user differently in create_and_enter_ns() function
> 
> 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>
> ---
>  tools/testing/selftests/capabilities/test_execve.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/capabilities/test_execve.c b/tools/testing/selftests/capabilities/test_execve.c
> index df0ef02b4036..8236150d377e 100644
> --- a/tools/testing/selftests/capabilities/test_execve.c
> +++ b/tools/testing/selftests/capabilities/test_execve.c
> @@ -96,11 +96,7 @@ 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",
> -- 
> 2.34.1
> 
Hi Shuah,
Please review this patchset.
Thanks,
Swarup
  

On 9/29/23 06:53, Swarup Laxman Kotiaklapudi wrote:
> Change namespace creation for root and non-root
> user differently in create_and_enter_ns() function
> 

Sorry for the delay on reviewing this.

Can you tell me more about why this change is needed and
include it in the change log.

thanks,
-- Shuah
  

On Tue, Nov 07, 2023 at 02:23:34PM -0700, Shuah Khan wrote:
> On 9/29/23 06:53, Swarup Laxman Kotiaklapudi wrote:
> > Change namespace creation for root and non-root
> > user differently in create_and_enter_ns() function
> > 
> 
> Sorry for the delay on reviewing this.
> 
> Can you tell me more about why this change is needed and
> include it in the change log.
> 
> thanks,
> -- Shuah

Hi Shuah,

This patchset was raised to fix below TODO:

"If we're already root, we could skip creating the userns."

Without this patchset, function create_and_enter_ns(),
at this path --> tools/testing/selftests/capabilities/test_execve.c
was as mentioned below:

static bool create_and_enter_ns(uid_t inner_uid)
{
   ....
   if (unshare(CLONE_NEWNS) == 0) {
       ....   
    } else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
       ....
     } else {
                ksft_exit_skip("must be root or be able to create a userns\n");
     }

     ...
}

To fix the TODO, above mentioned if block is executed if root user,
for normal user it enters inside 'else if' block.

Thanks,
Swarup