| Message ID | 99c11fa6-ad9a-830c-467e-6a56e78aecf8@android.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jan 30, 2018 at 11:00:04AM -0800, Mark Salyzyn wrote: > On 01/19/2018 09:41 AM, Stephen Smalley wrote: > > If we can't safely dereference the sock in these hooks, then that seems > > to point back to the approach used in my original code, where in > > ancient history I had sock_has_perm() take the socket and use its inode > > i_security field instead of the sock. commit > > 253bfae6e0ad97554799affa0266052968a45808 switched them to use the sock > > instead. > > Because of the nature of this problem (hard to duplicate, no clear path), I > am understandably not comfortable reverting and submitting for testing in > order to prove this point. It is disruptive because it changes several > subroutine call signatures. > > AFAIK this looks like a user request racing in without reference counting or > RCU grace period in the callers (could be viewed as not an issue with > security code). Effectively fixed in 4.9-stable, but broken in 4.4-stable. > > hygiene, KISS and small, is all I do feel comfortable to submit to > 4.4-stable without pulling in all the infrastructure improvements. > > -- Mark > > --- > security/selinux/hooks.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 34427384605d..be68992a28cb 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -4066,6 +4066,8 @@ static int sock_has_perm(struct task_struct *task, > struct sock *sk, u32 perms) > struct lsm_network_audit net = {0,}; > u32 tsid = task_sid(task); > > + if (!sksec) > + return -EFAULT; > if (sksec->sid == SECINITSID_KERNEL) > return 0; > This looks sane to me as a simple 4.4-only fix. If the SELinux maintainer acks it, I can easily queue this up. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 30, 2018 at 5:46 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Tue, Jan 30, 2018 at 11:00:04AM -0800, Mark Salyzyn wrote: >> On 01/19/2018 09:41 AM, Stephen Smalley wrote: >> > If we can't safely dereference the sock in these hooks, then that seems >> > to point back to the approach used in my original code, where in >> > ancient history I had sock_has_perm() take the socket and use its inode >> > i_security field instead of the sock. commit >> > 253bfae6e0ad97554799affa0266052968a45808 switched them to use the sock >> > instead. >> >> Because of the nature of this problem (hard to duplicate, no clear path), I >> am understandably not comfortable reverting and submitting for testing in >> order to prove this point. It is disruptive because it changes several >> subroutine call signatures. >> >> AFAIK this looks like a user request racing in without reference counting or >> RCU grace period in the callers (could be viewed as not an issue with >> security code). Effectively fixed in 4.9-stable, but broken in 4.4-stable. >> >> hygiene, KISS and small, is all I do feel comfortable to submit to >> 4.4-stable without pulling in all the infrastructure improvements. >> >> -- Mark >> >> --- >> security/selinux/hooks.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c >> index 34427384605d..be68992a28cb 100644 >> --- a/security/selinux/hooks.c >> +++ b/security/selinux/hooks.c >> @@ -4066,6 +4066,8 @@ static int sock_has_perm(struct task_struct *task, >> struct sock *sk, u32 perms) >> struct lsm_network_audit net = {0,}; >> u32 tsid = task_sid(task); >> >> + if (!sksec) >> + return -EFAULT; >> if (sksec->sid == SECINITSID_KERNEL) >> return 0; >> > > This looks sane to me as a simple 4.4-only fix. If the SELinux > maintainer acks it, I can easily queue this up. This revision addresses my concerns with Mark's previous patch. Acked-by: Paul Moore <paul@paul-moore.com>
On Wed, Jan 31, 2018 at 04:06:37AM -0500, Paul Moore wrote: > On Tue, Jan 30, 2018 at 5:46 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > > On Tue, Jan 30, 2018 at 11:00:04AM -0800, Mark Salyzyn wrote: > >> On 01/19/2018 09:41 AM, Stephen Smalley wrote: > >> > If we can't safely dereference the sock in these hooks, then that seems > >> > to point back to the approach used in my original code, where in > >> > ancient history I had sock_has_perm() take the socket and use its inode > >> > i_security field instead of the sock. commit > >> > 253bfae6e0ad97554799affa0266052968a45808 switched them to use the sock > >> > instead. > >> > >> Because of the nature of this problem (hard to duplicate, no clear path), I > >> am understandably not comfortable reverting and submitting for testing in > >> order to prove this point. It is disruptive because it changes several > >> subroutine call signatures. > >> > >> AFAIK this looks like a user request racing in without reference counting or > >> RCU grace period in the callers (could be viewed as not an issue with > >> security code). Effectively fixed in 4.9-stable, but broken in 4.4-stable. > >> > >> hygiene, KISS and small, is all I do feel comfortable to submit to > >> 4.4-stable without pulling in all the infrastructure improvements. > >> > >> -- Mark > >> > >> --- > >> security/selinux/hooks.c | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > >> index 34427384605d..be68992a28cb 100644 > >> --- a/security/selinux/hooks.c > >> +++ b/security/selinux/hooks.c > >> @@ -4066,6 +4066,8 @@ static int sock_has_perm(struct task_struct *task, > >> struct sock *sk, u32 perms) > >> struct lsm_network_audit net = {0,}; > >> u32 tsid = task_sid(task); > >> > >> + if (!sksec) > >> + return -EFAULT; > >> if (sksec->sid == SECINITSID_KERNEL) > >> return 0; > >> > > > > This looks sane to me as a simple 4.4-only fix. If the SELinux > > maintainer acks it, I can easily queue this up. > > This revision addresses my concerns with Mark's previous patch. > > Acked-by: Paul Moore <paul@paul-moore.com> Wonderful! Mark, can you resend this in a format I can apply it in? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 34427384605d..be68992a28cb 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4066,6 +4066,8 @@ static int sock_has_perm(struct task_struct *task, struct sock *sk, u32 perms) struct lsm_network_audit net = {0,}; u32 tsid = task_sid(task); + if (!sksec) + return -EFAULT; if (sksec->sid == SECINITSID_KERNEL) return 0;