| Message ID | 20220221131533.74238-1-richard_c_haines@btinternet.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | [V2] security/selinux: Always allow FIOCLEX and FIONCLEX | expand |
On Mon, Feb 21, 2022 at 8:15 AM Richard Haines <richard_c_haines@btinternet.com> wrote: > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which SELinux > always allows too. Furthermore, a failed FIOCLEX could result in a file > descriptor being leaked to a process that should not have access to it. > > As this patch removes access controls, a policy capability needs to be > enabled in policy to always allow these ioctls. > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > --- > V2 Change: Control via a policy capability. See this thread for discussion: > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > With this patch and the polcap enabled, the selinux-testsuite will fail: > ioctl/test at line 47 - Will need a fix. > > security/selinux/hooks.c | 7 +++++++ > security/selinux/include/policycap.h | 1 + > security/selinux/include/policycap_names.h | 3 ++- > security/selinux/include/security.h | 7 +++++++ > 4 files changed, 17 insertions(+), 1 deletion(-) Thanks Richard for putting together the v2 of this patch. As far as the test is concerned, it seems like the quick-n-dirty fix is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is everyone okay with that? At least that is what I'm going to do with my local copy that I use to validate the kernel-secnext builds unless someone has a better patch :) > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 5b6895e4f..030c41652 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd, > CAP_OPT_NONE, true); > break; > > + case FIOCLEX: > + case FIONCLEX: > + /* Must always succeed if polcap set, else default: */ > + if (selinux_policycap_ioctl_skip_cloexec()) > + break; > + fallthrough; > + The break/fallthrough looks like it might be a little more fragile than necessary, how about something like this: case FIOCLEX: case FIONCLEX: if (!selinux_policycap_ioctl_skip_cloexec()) error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); break; Yes, it does duplicate the default ioctl_has_perm() call, but since we are effectively deprecating this and locking the FIOCLEX/FIONCLEX behavior with this policy capability it seems okay to me (and preferable to relying on the fallthrough). Thoughts?
On Tue, 2022-02-22 at 18:28 -0500, Paul Moore wrote: > On Mon, Feb 21, 2022 at 8:15 AM Richard Haines > <richard_c_haines@btinternet.com> wrote: > > > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which > > SELinux > > always allows too. Furthermore, a failed FIOCLEX could result in a > > file > > descriptor being leaked to a process that should not have access to > > it. > > > > As this patch removes access controls, a policy capability needs to > > be > > enabled in policy to always allow these ioctls. > > > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > > --- > > V2 Change: Control via a policy capability. See this thread for > > discussion: > > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > > > With this patch and the polcap enabled, the selinux-testsuite will > > fail: > > ioctl/test at line 47 - Will need a fix. > > > > security/selinux/hooks.c | 7 +++++++ > > security/selinux/include/policycap.h | 1 + > > security/selinux/include/policycap_names.h | 3 ++- > > security/selinux/include/security.h | 7 +++++++ > > 4 files changed, 17 insertions(+), 1 deletion(-) > > Thanks Richard for putting together the v2 of this patch. > > As far as the test is concerned, it seems like the quick-n-dirty fix > is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is > everyone okay with that? At least that is what I'm going to do with > my local copy that I use to validate the kernel-secnext builds unless > someone has a better patch :) To fix this I was planning to submit a patch that would change the ioctl(FIOCLEX) tests to ioctl(FS_IOC_GETFSLABEL) as that would continue to test the xperms. > > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > > index 5b6895e4f..030c41652 100644 > > --- a/security/selinux/hooks.c > > +++ b/security/selinux/hooks.c > > @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct file > > *file, unsigned int cmd, > > CAP_OPT_NONE, true); > > break; > > > > + case FIOCLEX: > > + case FIONCLEX: > > + /* Must always succeed if polcap set, else default: > > */ > > + if (selinux_policycap_ioctl_skip_cloexec()) > > + break; > > + fallthrough; > > + > > The break/fallthrough looks like it might be a little more fragile > than necessary, how about something like this: > > case FIOCLEX: > case FIONCLEX: > if (!selinux_policycap_ioctl_skip_cloexec()) > error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); > break; > > Yes, it does duplicate the default ioctl_has_perm() call, but since > we > are effectively deprecating this and locking the FIOCLEX/FIONCLEX > behavior with this policy capability it seems okay to me (and > preferable to relying on the fallthrough). > > Thoughts? Yes I did ponder this and in my first attempt I had this before the switch(): /* Must always succeed if polcap set */ if (selinux_policycap_ioctl_skip_cloexec() && (cmd == FIOCLEX || cmd == FIONCLEX)) return 0; switch (cmd) { case FIONREAD: case FIBMAP: but changed to within the switch(), anyway I'm happy to resubmit a patch either way. >
On Wed, Feb 23, 2022 at 12:58 PM Richard Haines <richard_c_haines@btinternet.com> wrote: > On Tue, 2022-02-22 at 18:28 -0500, Paul Moore wrote: > > On Mon, Feb 21, 2022 at 8:15 AM Richard Haines > > <richard_c_haines@btinternet.com> wrote: > > > > > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which > > > SELinux > > > always allows too. Furthermore, a failed FIOCLEX could result in a > > > file > > > descriptor being leaked to a process that should not have access to > > > it. > > > > > > As this patch removes access controls, a policy capability needs to > > > be > > > enabled in policy to always allow these ioctls. > > > > > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > > > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > > > --- > > > V2 Change: Control via a policy capability. See this thread for > > > discussion: > > > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > > > > > With this patch and the polcap enabled, the selinux-testsuite will > > > fail: > > > ioctl/test at line 47 - Will need a fix. > > > > > > security/selinux/hooks.c | 7 +++++++ > > > security/selinux/include/policycap.h | 1 + > > > security/selinux/include/policycap_names.h | 3 ++- > > > security/selinux/include/security.h | 7 +++++++ > > > 4 files changed, 17 insertions(+), 1 deletion(-) > > > > Thanks Richard for putting together the v2 of this patch. > > > > As far as the test is concerned, it seems like the quick-n-dirty fix > > is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is > > everyone okay with that? At least that is what I'm going to do with > > my local copy that I use to validate the kernel-secnext builds unless > > someone has a better patch :) > > To fix this I was planning to submit a patch that would change the > ioctl(FIOCLEX) tests to ioctl(FS_IOC_GETFSLABEL) as that would continue > to test the xperms. That one seems to be implemented only by some filesystems. Is there any more generic one we could use? > > > > > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > > > index 5b6895e4f..030c41652 100644 > > > --- a/security/selinux/hooks.c > > > +++ b/security/selinux/hooks.c > > > @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct file > > > *file, unsigned int cmd, > > > CAP_OPT_NONE, true); > > > break; > > > > > > + case FIOCLEX: > > > + case FIONCLEX: > > > + /* Must always succeed if polcap set, else default: > > > */ > > > + if (selinux_policycap_ioctl_skip_cloexec()) > > > + break; > > > + fallthrough; > > > + > > > > The break/fallthrough looks like it might be a little more fragile > > than necessary, how about something like this: > > > > case FIOCLEX: > > case FIONCLEX: > > if (!selinux_policycap_ioctl_skip_cloexec()) > > error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); > > break; > > > > Yes, it does duplicate the default ioctl_has_perm() call, but since > > we > > are effectively deprecating this and locking the FIOCLEX/FIONCLEX > > behavior with this policy capability it seems okay to me (and > > preferable to relying on the fallthrough). > > > > Thoughts? > > Yes I did ponder this and in my first attempt I had this before the > switch(): > > /* Must always succeed if polcap set */ > if (selinux_policycap_ioctl_skip_cloexec() && > (cmd == FIOCLEX || cmd == FIONCLEX)) > return 0; > > switch (cmd) { > case FIONREAD: > case FIBMAP: > > but changed to within the switch(), anyway I'm happy to resubmit a > patch either way. I agree with Paul's suggestion. Better to duplicate the simple call than to complicate the code flow.
On Wed, 2022-02-23 at 13:12 +0100, Ondrej Mosnacek wrote: > On Wed, Feb 23, 2022 at 12:58 PM Richard Haines > <richard_c_haines@btinternet.com> wrote: > > On Tue, 2022-02-22 at 18:28 -0500, Paul Moore wrote: > > > On Mon, Feb 21, 2022 at 8:15 AM Richard Haines > > > <richard_c_haines@btinternet.com> wrote: > > > > > > > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which > > > > SELinux > > > > always allows too. Furthermore, a failed FIOCLEX could result > > > > in a > > > > file > > > > descriptor being leaked to a process that should not have > > > > access to > > > > it. > > > > > > > > As this patch removes access controls, a policy capability > > > > needs to > > > > be > > > > enabled in policy to always allow these ioctls. > > > > > > > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > > > > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > > > > --- > > > > V2 Change: Control via a policy capability. See this thread for > > > > discussion: > > > > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > > > > > > > With this patch and the polcap enabled, the selinux-testsuite > > > > will > > > > fail: > > > > ioctl/test at line 47 - Will need a fix. > > > > > > > > security/selinux/hooks.c | 7 +++++++ > > > > security/selinux/include/policycap.h | 1 + > > > > security/selinux/include/policycap_names.h | 3 ++- > > > > security/selinux/include/security.h | 7 +++++++ > > > > 4 files changed, 17 insertions(+), 1 deletion(-) > > > > > > Thanks Richard for putting together the v2 of this patch. > > > > > > As far as the test is concerned, it seems like the quick-n-dirty > > > fix > > > is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is > > > everyone okay with that? At least that is what I'm going to do > > > with > > > my local copy that I use to validate the kernel-secnext builds > > > unless > > > someone has a better patch :) > > > > To fix this I was planning to submit a patch that would change the > > ioctl(FIOCLEX) tests to ioctl(FS_IOC_GETFSLABEL) as that would > > continue > > to test the xperms. > > That one seems to be implemented only by some filesystems. Is there > any more generic one we could use? What about FS_IOC_GETFLAGS > > > > > > > > > > diff --git a/security/selinux/hooks.c > > > > b/security/selinux/hooks.c > > > > index 5b6895e4f..030c41652 100644 > > > > --- a/security/selinux/hooks.c > > > > +++ b/security/selinux/hooks.c > > > > @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct > > > > file > > > > *file, unsigned int cmd, > > > > CAP_OPT_NONE, > > > > true); > > > > break; > > > > > > > > + case FIOCLEX: > > > > + case FIONCLEX: > > > > + /* Must always succeed if polcap set, else > > > > default: > > > > */ > > > > + if (selinux_policycap_ioctl_skip_cloexec()) > > > > + break; > > > > + fallthrough; > > > > + > > > > > > The break/fallthrough looks like it might be a little more > > > fragile > > > than necessary, how about something like this: > > > > > > case FIOCLEX: > > > case FIONCLEX: > > > if (!selinux_policycap_ioctl_skip_cloexec()) > > > error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); > > > break; > > > > > > Yes, it does duplicate the default ioctl_has_perm() call, but > > > since > > > we > > > are effectively deprecating this and locking the FIOCLEX/FIONCLEX > > > behavior with this policy capability it seems okay to me (and > > > preferable to relying on the fallthrough). > > > > > > Thoughts? > > > > Yes I did ponder this and in my first attempt I had this before the > > switch(): > > > > /* Must always succeed if polcap set */ > > if (selinux_policycap_ioctl_skip_cloexec() && > > (cmd == FIOCLEX || cmd == FIONCLEX)) > > return 0; > > > > switch (cmd) { > > case FIONREAD: > > case FIBMAP: > > > > but changed to within the switch(), anyway I'm happy to resubmit a > > patch either way. > > I agree with Paul's suggestion. Better to duplicate the simple call > than to complicate the code flow. Okay will use Paul's. >
On Wed, Feb 23, 2022 at 7:43 AM Richard Haines <richard_c_haines@btinternet.com> wrote: > On Wed, 2022-02-23 at 13:12 +0100, Ondrej Mosnacek wrote: > > On Wed, Feb 23, 2022 at 12:58 PM Richard Haines > > <richard_c_haines@btinternet.com> wrote: > > > On Tue, 2022-02-22 at 18:28 -0500, Paul Moore wrote: > > > > On Mon, Feb 21, 2022 at 8:15 AM Richard Haines > > > > <richard_c_haines@btinternet.com> wrote: > > > > > > > > > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which > > > > > SELinux > > > > > always allows too. Furthermore, a failed FIOCLEX could result > > > > > in a > > > > > file > > > > > descriptor being leaked to a process that should not have > > > > > access to > > > > > it. > > > > > > > > > > As this patch removes access controls, a policy capability > > > > > needs to > > > > > be > > > > > enabled in policy to always allow these ioctls. > > > > > > > > > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > > > > > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > > > > > --- > > > > > V2 Change: Control via a policy capability. See this thread for > > > > > discussion: > > > > > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > > > > > > > > > With this patch and the polcap enabled, the selinux-testsuite > > > > > will > > > > > fail: > > > > > ioctl/test at line 47 - Will need a fix. > > > > > > > > > > security/selinux/hooks.c | 7 +++++++ > > > > > security/selinux/include/policycap.h | 1 + > > > > > security/selinux/include/policycap_names.h | 3 ++- > > > > > security/selinux/include/security.h | 7 +++++++ > > > > > 4 files changed, 17 insertions(+), 1 deletion(-) > > > > > > > > Thanks Richard for putting together the v2 of this patch. > > > > > > > > As far as the test is concerned, it seems like the quick-n-dirty > > > > fix > > > > is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is > > > > everyone okay with that? At least that is what I'm going to do > > > > with > > > > my local copy that I use to validate the kernel-secnext builds > > > > unless > > > > someone has a better patch :) > > > > > > To fix this I was planning to submit a patch that would change the > > > ioctl(FIOCLEX) tests to ioctl(FS_IOC_GETFSLABEL) as that would > > > continue > > > to test the xperms. > > > > That one seems to be implemented only by some filesystems. Is there > > any more generic one we could use? > > What about FS_IOC_GETFLAGS Unless I'm mistaken, FIGETBSZ should be largely fs independent. > > > > > diff --git a/security/selinux/hooks.c > > > > > b/security/selinux/hooks.c > > > > > index 5b6895e4f..030c41652 100644 > > > > > --- a/security/selinux/hooks.c > > > > > +++ b/security/selinux/hooks.c > > > > > @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct > > > > > file > > > > > *file, unsigned int cmd, > > > > > CAP_OPT_NONE, > > > > > true); > > > > > break; > > > > > > > > > > + case FIOCLEX: > > > > > + case FIONCLEX: > > > > > + /* Must always succeed if polcap set, else > > > > > default: > > > > > */ > > > > > + if (selinux_policycap_ioctl_skip_cloexec()) > > > > > + break; > > > > > + fallthrough; > > > > > + > > > > > > > > The break/fallthrough looks like it might be a little more > > > > fragile > > > > than necessary, how about something like this: > > > > > > > > case FIOCLEX: > > > > case FIONCLEX: > > > > if (!selinux_policycap_ioctl_skip_cloexec()) > > > > error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); > > > > break; > > > > > > > > Yes, it does duplicate the default ioctl_has_perm() call, but > > > > since > > > > we > > > > are effectively deprecating this and locking the FIOCLEX/FIONCLEX > > > > behavior with this policy capability it seems okay to me (and > > > > preferable to relying on the fallthrough). > > > > > > > > Thoughts? > > > > > > Yes I did ponder this and in my first attempt I had this before the > > > switch(): > > > > > > /* Must always succeed if polcap set */ > > > if (selinux_policycap_ioctl_skip_cloexec() && > > > (cmd == FIOCLEX || cmd == FIONCLEX)) > > > return 0; > > > > > > switch (cmd) { > > > case FIONREAD: > > > case FIBMAP: > > > > > > but changed to within the switch(), anyway I'm happy to resubmit a > > > patch either way. > > > > I agree with Paul's suggestion. Better to duplicate the simple call > > than to complicate the code flow. > > Okay will use Paul's. Thanks guys.
On Wed, Feb 23, 2022 at 4:36 PM Paul Moore <paul@paul-moore.com> wrote: > On Wed, Feb 23, 2022 at 7:43 AM Richard Haines > <richard_c_haines@btinternet.com> wrote: > > On Wed, 2022-02-23 at 13:12 +0100, Ondrej Mosnacek wrote: > > > On Wed, Feb 23, 2022 at 12:58 PM Richard Haines > > > <richard_c_haines@btinternet.com> wrote: > > > > On Tue, 2022-02-22 at 18:28 -0500, Paul Moore wrote: > > > > > On Mon, Feb 21, 2022 at 8:15 AM Richard Haines > > > > > <richard_c_haines@btinternet.com> wrote: > > > > > > > > > > > > These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which > > > > > > SELinux > > > > > > always allows too. Furthermore, a failed FIOCLEX could result > > > > > > in a > > > > > > file > > > > > > descriptor being leaked to a process that should not have > > > > > > access to > > > > > > it. > > > > > > > > > > > > As this patch removes access controls, a policy capability > > > > > > needs to > > > > > > be > > > > > > enabled in policy to always allow these ioctls. > > > > > > > > > > > > Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> > > > > > > Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> > > > > > > --- > > > > > > V2 Change: Control via a policy capability. See this thread for > > > > > > discussion: > > > > > > https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t > > > > > > > > > > > > With this patch and the polcap enabled, the selinux-testsuite > > > > > > will > > > > > > fail: > > > > > > ioctl/test at line 47 - Will need a fix. > > > > > > > > > > > > security/selinux/hooks.c | 7 +++++++ > > > > > > security/selinux/include/policycap.h | 1 + > > > > > > security/selinux/include/policycap_names.h | 3 ++- > > > > > > security/selinux/include/security.h | 7 +++++++ > > > > > > 4 files changed, 17 insertions(+), 1 deletion(-) > > > > > > > > > > Thanks Richard for putting together the v2 of this patch. > > > > > > > > > > As far as the test is concerned, it seems like the quick-n-dirty > > > > > fix > > > > > is to simply remove the ioctl(FIOCLEX) test in test_noioctl.c; is > > > > > everyone okay with that? At least that is what I'm going to do > > > > > with > > > > > my local copy that I use to validate the kernel-secnext builds > > > > > unless > > > > > someone has a better patch :) > > > > > > > > To fix this I was planning to submit a patch that would change the > > > > ioctl(FIOCLEX) tests to ioctl(FS_IOC_GETFSLABEL) as that would > > > > continue > > > > to test the xperms. > > > > > > That one seems to be implemented only by some filesystems. Is there > > > any more generic one we could use? > > > > What about FS_IOC_GETFLAGS > > Unless I'm mistaken, FIGETBSZ should be largely fs independent. Bah, nevermind, FIGETBSZ ends up in a FILE__GETATTR check. FS_IOC_GETFLAGS has the same problem. How about FIOQSIZE?
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5b6895e4f..030c41652 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3745,6 +3745,13 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd, CAP_OPT_NONE, true); break; + case FIOCLEX: + case FIONCLEX: + /* Must always succeed if polcap set, else default: */ + if (selinux_policycap_ioctl_skip_cloexec()) + break; + fallthrough; + /* default case assumes that the command will go * to the file's ioctl() function. */ diff --git a/security/selinux/include/policycap.h b/security/selinux/include/policycap.h index 2ec038efb..44d73dc32 100644 --- a/security/selinux/include/policycap.h +++ b/security/selinux/include/policycap.h @@ -11,6 +11,7 @@ enum { POLICYDB_CAPABILITY_CGROUPSECLABEL, POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION, POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS, + POLICYDB_CAPABILITY_IOCTL_CLOEXEC, __POLICYDB_CAPABILITY_MAX }; #define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1) diff --git a/security/selinux/include/policycap_names.h b/security/selinux/include/policycap_names.h index b89289f09..ebd64afe1 100644 --- a/security/selinux/include/policycap_names.h +++ b/security/selinux/include/policycap_names.h @@ -12,7 +12,8 @@ const char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX] = { "always_check_network", "cgroup_seclabel", "nnp_nosuid_transition", - "genfs_seclabel_symlinks" + "genfs_seclabel_symlinks", + "ioctl_skip_cloexec" }; #endif /* _SELINUX_POLICYCAP_NAMES_H_ */ diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index ac0ece013..8a789c22b 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -219,6 +219,13 @@ static inline bool selinux_policycap_genfs_seclabel_symlinks(void) return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS]); } +static inline bool selinux_policycap_ioctl_skip_cloexec(void) +{ + struct selinux_state *state = &selinux_state; + + return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_IOCTL_CLOEXEC]); +} + struct selinux_policy_convert_data; struct selinux_load_state {
These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which SELinux always allows too. Furthermore, a failed FIOCLEX could result in a file descriptor being leaked to a process that should not have access to it. As this patch removes access controls, a policy capability needs to be enabled in policy to always allow these ioctls. Based-on-patch-by: Demi Marie Obenour <demiobenour@gmail.com> Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> --- V2 Change: Control via a policy capability. See this thread for discussion: https://lore.kernel.org/selinux/CAHC9VhQEPxYP_KU56gAGNHKQaxucY8gSsHiUB42PVgADBAccRQ@mail.gmail.com/T/#t With this patch and the polcap enabled, the selinux-testsuite will fail: ioctl/test at line 47 - Will need a fix. security/selinux/hooks.c | 7 +++++++ security/selinux/include/policycap.h | 1 + security/selinux/include/policycap_names.h | 3 ++- security/selinux/include/security.h | 7 +++++++ 4 files changed, 17 insertions(+), 1 deletion(-)