| Message ID | 20221025113101.41132-1-wangweiyang2@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | device_cgroup: Roll back to original exceptions after copy failure | expand |
On Tue, Oct 25, 2022 at 7:02 AM Wang Weiyang <wangweiyang2@huawei.com> wrote: > > When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's > exceptions will be cleaned and A's behavior is changed to > DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's > whitelist. If copy failure occurs, just return leaving A to grant > permissions to all devices. And A may grant more permissions than > parent. > > Backup A's whitelist and recover original exceptions after copy > failure. > > Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") > Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> > --- > security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) On quick glance this looks reasonable to me, but I'm working with limited time connected to a network so I can't say I've given this a full and proper review; if a third party could spend some time to give this an additional review before I merge it I would greatly appreciate it. > diff --git a/security/device_cgroup.c b/security/device_cgroup.c > index a9f8c63a96d1..bef2b9285fb3 100644 > --- a/security/device_cgroup.c > +++ b/security/device_cgroup.c > @@ -82,6 +82,17 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) > return -ENOMEM; > } > > +static void dev_exceptions_move(struct list_head *dest, struct list_head *orig) > +{ > + struct dev_exception_item *ex, *tmp; > + > + lockdep_assert_held(&devcgroup_mutex); > + > + list_for_each_entry_safe(ex, tmp, orig, list) { > + list_move_tail(&ex->list, dest); > + } > +} > + > /* > * called under devcgroup_mutex > */ > @@ -604,11 +615,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > int count, rc = 0; > struct dev_exception_item ex; > struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent); > + struct dev_cgroup tmp_devcgrp; > > if (!capable(CAP_SYS_ADMIN)) > return -EPERM; > > memset(&ex, 0, sizeof(ex)); > + memset(&tmp_devcgrp, 0, sizeof(tmp_devcgrp)); > b = buffer; > > switch (*b) { > @@ -620,15 +633,27 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > > if (!may_allow_all(parent)) > return -EPERM; > - dev_exception_clean(devcgroup); > - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > - if (!parent) > + if (!parent) { > + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > + dev_exception_clean(devcgroup); > break; > + } > > + INIT_LIST_HEAD(&tmp_devcgrp.exceptions); > + rc = dev_exceptions_copy(&tmp_devcgrp.exceptions, > + &devcgroup->exceptions); > + if (rc) > + return rc; > + dev_exception_clean(devcgroup); > rc = dev_exceptions_copy(&devcgroup->exceptions, > &parent->exceptions); > - if (rc) > + if (rc) { > + dev_exceptions_move(&devcgroup->exceptions, > + &tmp_devcgrp.exceptions); > return rc; > + } > + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > + dev_exception_clean(&tmp_devcgrp); > break; > case DEVCG_DENY: > if (css_has_online_children(&devcgroup->css)) > -- > 2.17.1 >
On Tue, Oct 25, 2022 at 07:31:01PM +0800, Wang Weiyang wrote: > When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's > exceptions will be cleaned and A's behavior is changed to > DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's > whitelist. If copy failure occurs, just return leaving A to grant > permissions to all devices. And A may grant more permissions than > parent. > > Backup A's whitelist and recover original exceptions after copy > failure. > > Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") > Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> > --- > security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) > > diff --git a/security/device_cgroup.c b/security/device_cgroup.c > index a9f8c63a96d1..bef2b9285fb3 100644 > --- a/security/device_cgroup.c > +++ b/security/device_cgroup.c > @@ -82,6 +82,17 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) > return -ENOMEM; > } > > +static void dev_exceptions_move(struct list_head *dest, struct list_head *orig) > +{ > + struct dev_exception_item *ex, *tmp; > + > + lockdep_assert_held(&devcgroup_mutex); > + > + list_for_each_entry_safe(ex, tmp, orig, list) { > + list_move_tail(&ex->list, dest); > + } > +} > + > /* > * called under devcgroup_mutex > */ > @@ -604,11 +615,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > int count, rc = 0; > struct dev_exception_item ex; > struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent); > + struct dev_cgroup tmp_devcgrp; > > if (!capable(CAP_SYS_ADMIN)) > return -EPERM; > > memset(&ex, 0, sizeof(ex)); > + memset(&tmp_devcgrp, 0, sizeof(tmp_devcgrp)); > b = buffer; > > switch (*b) { > @@ -620,15 +633,27 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > > if (!may_allow_all(parent)) > return -EPERM; > - dev_exception_clean(devcgroup); > - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > - if (!parent) > + if (!parent) { > + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > + dev_exception_clean(devcgroup); > break; > + } > > + INIT_LIST_HEAD(&tmp_devcgrp.exceptions); > + rc = dev_exceptions_copy(&tmp_devcgrp.exceptions, > + &devcgroup->exceptions); > + if (rc) > + return rc; > + dev_exception_clean(devcgroup); > rc = dev_exceptions_copy(&devcgroup->exceptions, > &parent->exceptions); > - if (rc) > + if (rc) { > + dev_exceptions_move(&devcgroup->exceptions, > + &tmp_devcgrp.exceptions); > return rc; > + } > + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > + dev_exception_clean(&tmp_devcgrp); > break; > case DEVCG_DENY: > if (css_has_online_children(&devcgroup->css)) Reviewed-by: Aristeu Rozanski <aris@redhat.com>
Hi, Paul Can this patch be applied or something to improve? Thanks on 2022/10/28 19:19, Paul Moore wrote: > On Tue, Oct 25, 2022 at 7:02 AM Wang Weiyang <wangweiyang2@huawei.com> wrote: >> >> When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's >> exceptions will be cleaned and A's behavior is changed to >> DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's >> whitelist. If copy failure occurs, just return leaving A to grant >> permissions to all devices. And A may grant more permissions than >> parent. >> >> Backup A's whitelist and recover original exceptions after copy >> failure. >> >> Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") >> Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> >> --- >> security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- >> 1 file changed, 29 insertions(+), 4 deletions(-) > > On quick glance this looks reasonable to me, but I'm working with > limited time connected to a network so I can't say I've given this a > full and proper review; if a third party could spend some time to give > this an additional review before I merge it I would greatly appreciate > it. > >> diff --git a/security/device_cgroup.c b/security/device_cgroup.c >> index a9f8c63a96d1..bef2b9285fb3 100644 >> --- a/security/device_cgroup.c >> +++ b/security/device_cgroup.c >> @@ -82,6 +82,17 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) >> return -ENOMEM; >> } >> >> +static void dev_exceptions_move(struct list_head *dest, struct list_head *orig) >> +{ >> + struct dev_exception_item *ex, *tmp; >> + >> + lockdep_assert_held(&devcgroup_mutex); >> + >> + list_for_each_entry_safe(ex, tmp, orig, list) { >> + list_move_tail(&ex->list, dest); >> + } >> +} >> + >> /* >> * called under devcgroup_mutex >> */ >> @@ -604,11 +615,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, >> int count, rc = 0; >> struct dev_exception_item ex; >> struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent); >> + struct dev_cgroup tmp_devcgrp; >> >> if (!capable(CAP_SYS_ADMIN)) >> return -EPERM; >> >> memset(&ex, 0, sizeof(ex)); >> + memset(&tmp_devcgrp, 0, sizeof(tmp_devcgrp)); >> b = buffer; >> >> switch (*b) { >> @@ -620,15 +633,27 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, >> >> if (!may_allow_all(parent)) >> return -EPERM; >> - dev_exception_clean(devcgroup); >> - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; >> - if (!parent) >> + if (!parent) { >> + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; >> + dev_exception_clean(devcgroup); >> break; >> + } >> >> + INIT_LIST_HEAD(&tmp_devcgrp.exceptions); >> + rc = dev_exceptions_copy(&tmp_devcgrp.exceptions, >> + &devcgroup->exceptions); >> + if (rc) >> + return rc; >> + dev_exception_clean(devcgroup); >> rc = dev_exceptions_copy(&devcgroup->exceptions, >> &parent->exceptions); >> - if (rc) >> + if (rc) { >> + dev_exceptions_move(&devcgroup->exceptions, >> + &tmp_devcgrp.exceptions); >> return rc; >> + } >> + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; >> + dev_exception_clean(&tmp_devcgrp); >> break; >> case DEVCG_DENY: >> if (css_has_online_children(&devcgroup->css)) >> -- >> 2.17.1 >> > >
On Mon, Nov 14, 2022 at 10:54 PM wangweiyang <wangweiyang2@huawei.com> wrote: > > Hi, Paul > Can this patch be applied or something to improve? Possibly. I need to find the time to properly review the patch; it's in my queue, I just haven't gotten to it yet. I'll reply to the patch posting with either a note that the patch has been merged, or a set of questions/feedback that needs to be resolved. If you haven't heard from me on the patch, the best thing you can do is exercise patience. > on 2022/10/28 19:19, Paul Moore wrote: > > On Tue, Oct 25, 2022 at 7:02 AM Wang Weiyang <wangweiyang2@huawei.com> wrote: > >> > >> When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's > >> exceptions will be cleaned and A's behavior is changed to > >> DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's > >> whitelist. If copy failure occurs, just return leaving A to grant > >> permissions to all devices. And A may grant more permissions than > >> parent. > >> > >> Backup A's whitelist and recover original exceptions after copy > >> failure. > >> > >> Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") > >> Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> > >> --- > >> security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- > >> 1 file changed, 29 insertions(+), 4 deletions(-) > > > > On quick glance this looks reasonable to me, but I'm working with > > limited time connected to a network so I can't say I've given this a > > full and proper review; if a third party could spend some time to give > > this an additional review before I merge it I would greatly appreciate > > it. > > > >> diff --git a/security/device_cgroup.c b/security/device_cgroup.c > >> index a9f8c63a96d1..bef2b9285fb3 100644 > >> --- a/security/device_cgroup.c > >> +++ b/security/device_cgroup.c > >> @@ -82,6 +82,17 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) > >> return -ENOMEM; > >> } > >> > >> +static void dev_exceptions_move(struct list_head *dest, struct list_head *orig) > >> +{ > >> + struct dev_exception_item *ex, *tmp; > >> + > >> + lockdep_assert_held(&devcgroup_mutex); > >> + > >> + list_for_each_entry_safe(ex, tmp, orig, list) { > >> + list_move_tail(&ex->list, dest); > >> + } > >> +} > >> + > >> /* > >> * called under devcgroup_mutex > >> */ > >> @@ -604,11 +615,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > >> int count, rc = 0; > >> struct dev_exception_item ex; > >> struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent); > >> + struct dev_cgroup tmp_devcgrp; > >> > >> if (!capable(CAP_SYS_ADMIN)) > >> return -EPERM; > >> > >> memset(&ex, 0, sizeof(ex)); > >> + memset(&tmp_devcgrp, 0, sizeof(tmp_devcgrp)); > >> b = buffer; > >> > >> switch (*b) { > >> @@ -620,15 +633,27 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, > >> > >> if (!may_allow_all(parent)) > >> return -EPERM; > >> - dev_exception_clean(devcgroup); > >> - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > >> - if (!parent) > >> + if (!parent) { > >> + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > >> + dev_exception_clean(devcgroup); > >> break; > >> + } > >> > >> + INIT_LIST_HEAD(&tmp_devcgrp.exceptions); > >> + rc = dev_exceptions_copy(&tmp_devcgrp.exceptions, > >> + &devcgroup->exceptions); > >> + if (rc) > >> + return rc; > >> + dev_exception_clean(devcgroup); > >> rc = dev_exceptions_copy(&devcgroup->exceptions, > >> &parent->exceptions); > >> - if (rc) > >> + if (rc) { > >> + dev_exceptions_move(&devcgroup->exceptions, > >> + &tmp_devcgrp.exceptions); > >> return rc; > >> + } > >> + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; > >> + dev_exception_clean(&tmp_devcgrp); > >> break; > >> case DEVCG_DENY: > >> if (css_has_online_children(&devcgroup->css)) > >> -- > >> 2.17.1 > >> > > > >
On Tue, Oct 25, 2022 at 7:02 AM Wang Weiyang <wangweiyang2@huawei.com> wrote: > > When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's > exceptions will be cleaned and A's behavior is changed to > DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's > whitelist. If copy failure occurs, just return leaving A to grant > permissions to all devices. And A may grant more permissions than > parent. > > Backup A's whitelist and recover original exceptions after copy > failure. > > Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") > Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> > --- > security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) Merged into lsm/next, but with a stable@vger tag. Normally I would merge something like this into lsm/stable-X.Y and send it up to Linus after a few days, but I'd really like this to spend some time in linux-next before going up to Linus.
On 2022/11/17 7:33, Paul Moore wrote: > On Tue, Oct 25, 2022 at 7:02 AM Wang Weiyang <wangweiyang2@huawei.com> wrote: >> >> When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's >> exceptions will be cleaned and A's behavior is changed to >> DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's >> whitelist. If copy failure occurs, just return leaving A to grant >> permissions to all devices. And A may grant more permissions than >> parent. >> >> Backup A's whitelist and recover original exceptions after copy >> failure. >> >> Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") >> Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> >> --- >> security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- >> 1 file changed, 29 insertions(+), 4 deletions(-) > > Merged into lsm/next, but with a stable@vger tag. Normally I would > merge something like this into lsm/stable-X.Y and send it up to Linus > after a few days, but I'd really like this to spend some time in > linux-next before going up to Linus. Thanks Paul. This sounds fine.
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index a9f8c63a96d1..bef2b9285fb3 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -82,6 +82,17 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) return -ENOMEM; } +static void dev_exceptions_move(struct list_head *dest, struct list_head *orig) +{ + struct dev_exception_item *ex, *tmp; + + lockdep_assert_held(&devcgroup_mutex); + + list_for_each_entry_safe(ex, tmp, orig, list) { + list_move_tail(&ex->list, dest); + } +} + /* * called under devcgroup_mutex */ @@ -604,11 +615,13 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, int count, rc = 0; struct dev_exception_item ex; struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent); + struct dev_cgroup tmp_devcgrp; if (!capable(CAP_SYS_ADMIN)) return -EPERM; memset(&ex, 0, sizeof(ex)); + memset(&tmp_devcgrp, 0, sizeof(tmp_devcgrp)); b = buffer; switch (*b) { @@ -620,15 +633,27 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, if (!may_allow_all(parent)) return -EPERM; - dev_exception_clean(devcgroup); - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; - if (!parent) + if (!parent) { + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; + dev_exception_clean(devcgroup); break; + } + INIT_LIST_HEAD(&tmp_devcgrp.exceptions); + rc = dev_exceptions_copy(&tmp_devcgrp.exceptions, + &devcgroup->exceptions); + if (rc) + return rc; + dev_exception_clean(devcgroup); rc = dev_exceptions_copy(&devcgroup->exceptions, &parent->exceptions); - if (rc) + if (rc) { + dev_exceptions_move(&devcgroup->exceptions, + &tmp_devcgrp.exceptions); return rc; + } + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; + dev_exception_clean(&tmp_devcgrp); break; case DEVCG_DENY: if (css_has_online_children(&devcgroup->css))
When add the 'a *:* rwm' entry to devcgroup A's whitelist, at first A's exceptions will be cleaned and A's behavior is changed to DEVCG_DEFAULT_ALLOW. Then parent's exceptions will be copyed to A's whitelist. If copy failure occurs, just return leaving A to grant permissions to all devices. And A may grant more permissions than parent. Backup A's whitelist and recover original exceptions after copy failure. Fixes: 4cef7299b478 ("device_cgroup: add proper checking when changing default behavior") Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> --- security/device_cgroup.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-)