Re: [PATCH -next] selinux: Fix memleak in security_read_state_kernel

[xiujianfeng <xiujianfeng@xxxxxxxxxx>]

在 2022/6/14 20:57, Ondrej Mosnacek 写道:
> On Mon, Jun 13, 2022 at 4:02 PM Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> wrote:
> > In this function, it directly returns the result of __security_read_policy
> > without freeing the allocated memory in *data, cause memory leak issue,
> > so free the memory if __security_read_policy failed.
> >
> > Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
> > ---
> >   security/selinux/ss/services.c | 9 ++++++++-
> >   1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> > index 69b2734311a6..fe5fcf571c56 100644
> > --- a/security/selinux/ss/services.c
> > +++ b/security/selinux/ss/services.c
> > @@ -4048,6 +4048,7 @@ int security_read_policy(struct selinux_state *state,
> >   int security_read_state_kernel(struct selinux_state *state,
> >                                 void **data, size_t *len)
> >   {
> > +       int err;
> >          struct selinux_policy *policy;
> >
> >          policy = rcu_dereference_protected(
> > @@ -4060,5 +4061,11 @@ int security_read_state_kernel(struct selinux_state *state,
> >          if (!*data)
> >                  return -ENOMEM;
> >
> > -       return __security_read_policy(policy, *data, len);
> > +       err = __security_read_policy(policy, *data, len);
> > +       if (err) {
> > +               vfree(*data);
> > +               *data = NULL;
> > +               *len = 0;
> > +       }
> > +       return err;
> >   }
> > --
> > 2.17.1
> security_read_policy() defined a few lines above has the same pattern
> (just with vmalloc_user() in place of vmalloc()). Would you like to
> send another patch to fix that function as well?
No problem, patch already sent.
>