| Message ID | 20210714161734.256246-1-anthony.perard@citrix.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [XEN] xen: allow XSM_FLASK_POLICY only if checkpolicy binary is available | expand |
On Wed, Jul 14, 2021 at 12:23 PM Anthony PERARD <anthony.perard@citrix.com> wrote: > > This will help prevent the CI loop from having build failures when > `checkpolicy` isn't available, when doing "randconfig" jobs. > > Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
On 14/07/2021 17:17, Anthony PERARD wrote: > This will help prevent the CI loop from having build failures when > `checkpolicy` isn't available, when doing "randconfig" jobs. > > Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Thankyou for doing this. Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
On 14.07.2021 18:17, Anthony PERARD wrote: > --- a/xen/common/Kconfig > +++ b/xen/common/Kconfig > @@ -25,6 +25,9 @@ config GRANT_TABLE > config HAS_ALTERNATIVE > bool > > +config HAS_CHECKPOLICY > + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) > + This is no different from other aspects of "Kconfig vs tool chain capabilities" sent out last August to start a discussion about whether we really want such. Besides Jürgen no-one cared to reply iirc, which to me means no-one really cares one way or the other. Which I didn't think was the case ... So here we are again, with all the same questions still open. I'm not going to nack the patch, because there's an immediate purpose / need, but I also can't avoid commenting (and I won't put my name on it in any positive way, i.e. also not as a committer; if anything then to record my reservations). Independent of this I'd like to raise the question of whether the chosen placement is optimal. Other capability checks live in xen/Kconfig. Jan
On Thu, Jul 15, 2021 at 08:25:31AM +0200, Jan Beulich wrote: > On 14.07.2021 18:17, Anthony PERARD wrote: > > --- a/xen/common/Kconfig > > +++ b/xen/common/Kconfig > > @@ -25,6 +25,9 @@ config GRANT_TABLE > > config HAS_ALTERNATIVE > > bool > > > > +config HAS_CHECKPOLICY > > + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) > > + > > This is no different from other aspects of "Kconfig vs tool chain > capabilities" sent out last August to start a discussion about > whether we really want such. Besides Jürgen no-one cared to reply > iirc, which to me means no-one really cares one way or the other. > Which I didn't think was the case ... So here we are again, with > all the same questions still open. It's true, I don't really care either way. But with maybe a slight preference for testing the environment every time `make` is run. But there weren't really a precedent for testing in Makefile and using the result in Kconfig (or I don't think there is). > I'm not going to nack the patch, because there's an immediate > purpose / need, but I also can't avoid commenting (and I won't > put my name on it in any positive way, i.e. also not as a > committer; if anything then to record my reservations). I've prepared an update which test in Makefile, which I hope you'll like better. Thanks,
On 15/07/2021 07:25, Jan Beulich wrote: > On 14.07.2021 18:17, Anthony PERARD wrote: >> --- a/xen/common/Kconfig >> +++ b/xen/common/Kconfig >> @@ -25,6 +25,9 @@ config GRANT_TABLE >> config HAS_ALTERNATIVE >> bool >> >> +config HAS_CHECKPOLICY >> + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) >> + > This is no different from other aspects of "Kconfig vs tool chain > capabilities" sent out last August to start a discussion about > whether we really want such. Besides Jürgen no-one cared to reply > iirc, which to me means no-one really cares one way or the other. You know full well that upgrading Kconfig was specifically to be able to use this functionality, and you know full well that I firmly support using this mechanism, because we've had both of these arguments several times before. The absence of replies doesn't mean people agree with you, or even that they don't care. It either means people didn't read the email, or didn't have time to reply, or didn't feel like wasting time rehashing the same arguments yet again with no hope for progress. If you really insist on refusing to features specifically intended for the improvement of our build processes, then call a vote so we can be done with the argument for once and for all. ~Andrew
On 16.07.2021 15:15, Andrew Cooper wrote: > On 15/07/2021 07:25, Jan Beulich wrote: >> On 14.07.2021 18:17, Anthony PERARD wrote: >>> --- a/xen/common/Kconfig >>> +++ b/xen/common/Kconfig >>> @@ -25,6 +25,9 @@ config GRANT_TABLE >>> config HAS_ALTERNATIVE >>> bool >>> >>> +config HAS_CHECKPOLICY >>> + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) >>> + >> This is no different from other aspects of "Kconfig vs tool chain >> capabilities" sent out last August to start a discussion about >> whether we really want such. Besides Jürgen no-one cared to reply >> iirc, which to me means no-one really cares one way or the other. > > You know full well that upgrading Kconfig was specifically to be able to > use this functionality, and you know full well that I firmly support > using this mechanism, because we've had both of these arguments several > times before. > > The absence of replies doesn't mean people agree with you, or even that > they don't care. It either means people didn't read the email, or > didn't have time to reply, or didn't feel like wasting time rehashing > the same arguments yet again with no hope for progress. > > > If you really insist on refusing to features specifically intended for > the improvement of our build processes, then call a vote so we can be > done with the argument for once and for all. I'm sorry Andrew, but this is not a way to discuss controversial items. Back at the time you were pointing me at a discussion at a summit that I didn't recall and hence presumably didn't attend for whatever reason. Whatever may have been the result of such a discussion imo _has_ to be under the precondition that no other contrary arguments arise. I do not recall there having been spelled out up front this specific purpose of upgrading kconfig, and even if it was spelled out, the ramifications may not have become clear until the actual first uses were proposed. It has to be possible to change views at such a point even for people who did signal agreement earlier on. Not to speak of unaware ones. Further iirc it was you who told me to start a mail thread about the issue. Which I did. And now you say "... didn't feel like wasting time rehashing the same arguments yet again with no hope for progress"? Can you please point me to a place where those "same arguments" are put down in writing, including reasons why they were either turned down or considered of less relevance? I can't help the feeling that when our opinions don't match you try to silence me by whatever means you find suitable - ignoring my input, claiming my earlier agreement, denying me any influence, etc. I'm afraid I have to say that I don't think this is a way to run a community project. The only two ways to get past my objections (or really just reservations here) are to either convince me (which you don't appear to be willing to) or to outvote me (which you haven't tried at all so far if I'm not mistaken). Jan
> On Jul 14, 2021, at 5:17 PM, Anthony PERARD <anthony.perard@citrix.com> wrote: > > This will help prevent the CI loop from having build failures when > `checkpolicy` isn't available, when doing "randconfig" jobs. Hang on, just to clarify what’s going on here. ‘randconfig’ is setting CONFIG_XSM_FLASK_POLICY in the .config file; and then when the build happens, we error out because one of the required components isn’t there. What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them? Or does the randconfig test run kConfig one more time, at which point *then* the .config will be disabled? The former I think is broken; the latter I think is fine. -George
On 16.07.21 17:26, George Dunlap wrote: > > >> On Jul 14, 2021, at 5:17 PM, Anthony PERARD <anthony.perard@citrix.com> wrote: >> >> This will help prevent the CI loop from having build failures when >> `checkpolicy` isn't available, when doing "randconfig" jobs. > > Hang on, just to clarify what’s going on here. > > ‘randconfig’ is setting CONFIG_XSM_FLASK_POLICY in the .config file; and then when the build happens, we error out because one of the required components isn’t there. > > What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them? > > Or does the randconfig test run kConfig one more time, at which point *then* the .config will be disabled? > > The former I think is broken; the latter I think is fine. I still think that Kconfig should not disable explicit settings due to tools not being available. I'd be fine with trimodal settings for such parameters: - Off - On - On if tools available And the last one could even be the default. But anyone wanting to test a specific option or to enable an option should not be catched by surprise because some internal modification is requesting another tool which happens not to be available. BTW, the same applies to ./configure options for tools. I really don't like that some components are silently not built because e.g. a header file is not available. I'd rather have the possibility to tell ./configure that I want everything built and let the build fail if that is not possible. Juergen
On Fri, Jul 16, 2021 at 04:26:39PM +0100, George Dunlap wrote: > > > > On Jul 14, 2021, at 5:17 PM, Anthony PERARD <anthony.perard@citrix.com> wrote: > > > > This will help prevent the CI loop from having build failures when > > `checkpolicy` isn't available, when doing "randconfig" jobs. > > Hang on, just to clarify what’s going on here. > > ‘randconfig’ is setting CONFIG_XSM_FLASK_POLICY in the .config file; and then when the build happens, we error out because one of the required components isn’t there. > > What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them? > > Or does the randconfig test run kConfig one more time, at which point *then* the .config will be disabled? > > The former I think is broken; the latter I think is fine. That's right, Xen's build system is broken. Kconfig doesn't say whether a given .config is correct or not, it removes non existing CONFIG_* setting as well as those that are missing dependencies. This isn't new, this is the default, this is how Linux is using Kconfig. But there's a way out of that. There's an option to prevent Kconfig from updating .config, setting KCONFIG_NOSILENTUPDATE in the environment (see docs/misc/kconfig.rst). But that won't work as expected with the Xen build system because to update the config via "syncconfig" doesn't prevent the build system from building Xen (and probably fail later). If it were working, build would fail, and user would have to run "oldconfig" or other *config targets, and check the result (diff .config.old .config). Cheers,
On 16/07/2021 16:26, George Dunlap wrote: > >> On Jul 14, 2021, at 5:17 PM, Anthony PERARD <anthony.perard@citrix.com> wrote: >> >> This will help prevent the CI loop from having build failures when >> `checkpolicy` isn't available, when doing "randconfig" jobs. > Hang on, just to clarify what’s going on here. > > ‘randconfig’ is setting CONFIG_XSM_FLASK_POLICY in the .config file; and then when the build happens, we error out because one of the required components isn’t there. > > What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them? Yes, but that's how ~everything in the Xen and Linux build works currently. What this new version will do is produce a config/build combo, with the config reporting that CONFIG_XSM_FLASK_POLICY was not active. This is a damnsignt better than the "old" way of doing feature checks in the makefiles, where there is no trace that the build system disabled a feature because your compiler was too old. ~Andrew
On Fri, Jul 16, 2021 at 02:15:28PM +0100, Andrew Cooper wrote: > On 15/07/2021 07:25, Jan Beulich wrote: > > On 14.07.2021 18:17, Anthony PERARD wrote: > >> --- a/xen/common/Kconfig > >> +++ b/xen/common/Kconfig > >> @@ -25,6 +25,9 @@ config GRANT_TABLE > >> config HAS_ALTERNATIVE > >> bool > >> > >> +config HAS_CHECKPOLICY > >> + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) > >> + > > This is no different from other aspects of "Kconfig vs tool chain > > capabilities" sent out last August to start a discussion about > > whether we really want such. Besides Jürgen no-one cared to reply > > iirc, which to me means no-one really cares one way or the other. > > You know full well that upgrading Kconfig was specifically to be able to > use this functionality, and you know full well that I firmly support To be honest, I've upgraded Kconfig mostly because I needed to start somewhere with upgrading our build system to look more like Kbuild. I may have adding `CC --version` and some other CONFIG_* running shells, but I don't think anymore that is a necessary things to do, it just look cleaner. > using this mechanism, because we've had both of these arguments several > times before. I'd like to read about your (or someone else's) arguments in favor of doing more in Kconfig only, do you have links (or maybe subject, keyword) to look at? I think I understand Jan's arguments. Cheers,
On Fri, Jul 16, 2021 at 04:26:39PM +0100, George Dunlap wrote:
> What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them?
FYI, silenty disabling unavailable config options is actually
documented, in "INSTALL", section "Xen Hypervisor". ;-) Well kind of.
On 16.07.2021 18:14, Andrew Cooper wrote: > On 16/07/2021 16:26, George Dunlap wrote: >> >>> On Jul 14, 2021, at 5:17 PM, Anthony PERARD <anthony.perard@citrix.com> wrote: >>> >>> This will help prevent the CI loop from having build failures when >>> `checkpolicy` isn't available, when doing "randconfig" jobs. >> Hang on, just to clarify what’s going on here. >> >> ‘randconfig’ is setting CONFIG_XSM_FLASK_POLICY in the .config file; and then when the build happens, we error out because one of the required components isn’t there. >> >> What this patch does is to make it so that if someone explicitly sets CONFIG_XSM_FLASK_POLICY=y, but doesn’t have checkpolicy, the build system will silently disable the policy behind their backs without telling them? > > Yes, but that's how ~everything in the Xen and Linux build works currently. > > What this new version will do is produce a config/build combo, with the > config reporting that CONFIG_XSM_FLASK_POLICY was not active. > > This is a damnsignt better than the "old" way of doing feature checks in > the makefiles, where there is no trace that the build system disabled a > feature because your compiler was too old. Disabling features at build time is of course no better than disabling them at configure time. Instead, if a chose configuration cannot be built, the build should fail - ideally with an error message clearly telling people what the reason is and what they can do about it. Jan
diff --git a/Config.mk b/Config.mk index d08fa8d60dd7..97d3633706b3 100644 --- a/Config.mk +++ b/Config.mk @@ -137,12 +137,6 @@ export XEN_HAS_BUILD_ID=y build_id_linker := --build-id=sha1 endif -ifndef XEN_HAS_CHECKPOLICY - CHECKPOLICY ?= checkpolicy - XEN_HAS_CHECKPOLICY := $(shell $(CHECKPOLICY) -h 2>&1 | grep -q xen && echo y || echo n) - export XEN_HAS_CHECKPOLICY -endif - define buildmakevars2shellvars export PREFIX="$(prefix)"; \ export XEN_SCRIPT_DIR="$(XEN_SCRIPT_DIR)"; \ diff --git a/xen/Makefile b/xen/Makefile index 8023680ffbf2..a60e49903d0c 100644 --- a/xen/Makefile +++ b/xen/Makefile @@ -17,6 +17,8 @@ export XEN_BUILD_HOST ?= $(shell hostname) PYTHON_INTERPRETER := $(word 1,$(shell which python3 python python2 2>/dev/null) python) export PYTHON ?= $(PYTHON_INTERPRETER) +export CHECKPOLICY ?= checkpolicy + export BASEDIR := $(CURDIR) export XEN_ROOT := $(BASEDIR)/.. diff --git a/xen/common/Kconfig b/xen/common/Kconfig index 0ddd18e11af3..13537e460b8f 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -25,6 +25,9 @@ config GRANT_TABLE config HAS_ALTERNATIVE bool +config HAS_CHECKPOLICY + def_bool $(success,$(CHECKPOLICY) -h 2>&1 | grep -q xen) + config HAS_COMPAT bool @@ -235,8 +238,8 @@ config XSM_FLASK_AVC_STATS config XSM_FLASK_POLICY bool "Compile Xen with a built-in FLASK security policy" - default y if "$(XEN_HAS_CHECKPOLICY)" = "y" - depends on XSM_FLASK + default y + depends on XSM_FLASK && HAS_CHECKPOLICY ---help--- This includes a default XSM policy in the hypervisor so that the bootloader does not need to load a policy to get sane behavior from an
This will help prevent the CI loop from having build failures when `checkpolicy` isn't available, when doing "randconfig" jobs. Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> --- Config.mk | 6 ------ xen/Makefile | 2 ++ xen/common/Kconfig | 7 +++++-- 3 files changed, 7 insertions(+), 8 deletions(-)