On Thu, Jun 28, 2018 at 8:23 PM Paul Moore <p...@paul-moore.com> wrote: > On Tue, Jun 26, 2018 at 8:15 AM Stephen Smalley <s...@tycho.nsa.gov> wrote: > > On 06/25/2018 12:34 PM, Jann Horn wrote: > > > If a user is accessing a file in selinuxfs with a pointer to a userspace > > > buffer that is backed by e.g. a userfaultfd, the userspace access can > > > stall indefinitely, which can block fsi->mutex if it is held. > > > > > > For sel_read_policy(), remove the locking, since this method doesn't seem > > > to access anything that requires locking. > > > > > > For sel_read_bool(), move the user access below the locked region. > > > > > > For sel_write_bool() and sel_commit_bools_write(), move the user access > > > up above the locked region. > > > > > > Cc: sta...@vger.kernel.org > > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > > > Signed-off-by: Jann Horn <ja...@google.com> > > > > Only question I have is wrt the Fixes line, i.e. was this an issue until > > userfaultfd was introduced, and if not, > > do we need it to be back-ported any further than the commit which > > introduced it. > > Considering we are talking about v2.6.12 I have to wonder if anyone is > bothering with backports for kernels that old. Even the RHEL-5.x > based systems are at least on v2.6.18. > > Regardless, I think this is fine to merge as-is; thanks everyone.
FYI, I did have to remove the "fsi" variable from sel_read_policy() to keep the compiler happy. Please double check to make sure your code compiles cleanly in the future. -- paul moore www.paul-moore.com _______________________________________________ Selinux mailing list Selinux@tycho.nsa.gov To unsubscribe, send email to selinux-le...@tycho.nsa.gov. To get help, send an email containing "help" to selinux-requ...@tycho.nsa.gov.