diff mbox series

selinux: fix memory leak in policydb_init()

Message ID 20190725105243.28404-1-omosnace@redhat.com (mailing list archive)
State Accepted
Headers show
Series selinux: fix memory leak in policydb_init() | expand

Commit Message

Ondrej Mosnacek July 25, 2019, 10:52 a.m. UTC
Since roles_init() adds some entries to the role hash table, we need to
destroy also its keys/values on error, otherwise we get a memory leak in
the error path.

Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 security/selinux/ss/policydb.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Paul Moore July 26, 2019, 10:27 p.m. UTC | #1
On Thu, Jul 25, 2019 at 6:52 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> Since roles_init() adds some entries to the role hash table, we need to
> destroy also its keys/values on error, otherwise we get a memory leak in
> the error path.
>
> Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  security/selinux/ss/policydb.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> index daecdfb15a9c..38d0083204f1 100644
> --- a/security/selinux/ss/policydb.c
> +++ b/security/selinux/ss/policydb.c
> @@ -274,6 +274,8 @@ static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
>         return v;
>  }
>
> +static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap);

I'm prefer not to use forward declarations if they can be avoided, and
in this particular case it looks like we can move the *_destroy
functions up just below policydb_lookup_compat() and avoid the forward
declaration while keeping some sanity to the layout of the file.

Yes, the patch does become much larger (378 lines changed in the test
patch I just did), but I think the end result is cleaner.

>  /*
>   * Initialize a policy database structure.
>   */
> @@ -321,8 +323,10 @@ static int policydb_init(struct policydb *p)
>  out:
>         hashtab_destroy(p->filename_trans);
>         hashtab_destroy(p->range_tr);
> -       for (i = 0; i < SYM_NUM; i++)
> +       for (i = 0; i < SYM_NUM; i++) {
> +               hashtab_map(p->symtab[i].table, destroy_f[i], NULL);
>                 hashtab_destroy(p->symtab[i].table);
> +       }
>         return rc;
>  }
>
> --
> 2.21.0
>
Ondrej Mosnacek July 29, 2019, 7:33 a.m. UTC | #2
On Sat, Jul 27, 2019 at 12:27 AM Paul Moore <paul@paul-moore.com> wrote:
> On Thu, Jul 25, 2019 at 6:52 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> > Since roles_init() adds some entries to the role hash table, we need to
> > destroy also its keys/values on error, otherwise we get a memory leak in
> > the error path.
> >
> > Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> > ---
> >  security/selinux/ss/policydb.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> > index daecdfb15a9c..38d0083204f1 100644
> > --- a/security/selinux/ss/policydb.c
> > +++ b/security/selinux/ss/policydb.c
> > @@ -274,6 +274,8 @@ static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
> >         return v;
> >  }
> >
> > +static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap);
>
> I'm prefer not to use forward declarations if they can be avoided, and
> in this particular case it looks like we can move the *_destroy
> functions up just below policydb_lookup_compat() and avoid the forward
> declaration while keeping some sanity to the layout of the file.
>
> Yes, the patch does become much larger (378 lines changed in the test
> patch I just did), but I think the end result is cleaner.

OK, that'ts reasonable. I'll post an updated v2.

>
> >  /*
> >   * Initialize a policy database structure.
> >   */
> > @@ -321,8 +323,10 @@ static int policydb_init(struct policydb *p)
> >  out:
> >         hashtab_destroy(p->filename_trans);
> >         hashtab_destroy(p->range_tr);
> > -       for (i = 0; i < SYM_NUM; i++)
> > +       for (i = 0; i < SYM_NUM; i++) {
> > +               hashtab_map(p->symtab[i].table, destroy_f[i], NULL);
> >                 hashtab_destroy(p->symtab[i].table);
> > +       }
> >         return rc;
> >  }
> >
> > --
> > 2.21.0
> >
>
>
> --
> paul moore
> www.paul-moore.com
Paul Moore July 31, 2019, 9:10 p.m. UTC | #3
On Thu, Jul 25, 2019 at 6:52 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> Since roles_init() adds some entries to the role hash table, we need to
> destroy also its keys/values on error, otherwise we get a memory leak in
> the error path.
>
> Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  security/selinux/ss/policydb.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

As discussed in the v2 thread, I've gone ahead and merge this patch
into selinux/stable-5.3.  Assuming all is well I'll send this to Linus
later this week.
diff mbox series

Patch

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index daecdfb15a9c..38d0083204f1 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -274,6 +274,8 @@  static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
 	return v;
 }
 
+static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap);
+
 /*
  * Initialize a policy database structure.
  */
@@ -321,8 +323,10 @@  static int policydb_init(struct policydb *p)
 out:
 	hashtab_destroy(p->filename_trans);
 	hashtab_destroy(p->range_tr);
-	for (i = 0; i < SYM_NUM; i++)
+	for (i = 0; i < SYM_NUM; i++) {
+		hashtab_map(p->symtab[i].table, destroy_f[i], NULL);
 		hashtab_destroy(p->symtab[i].table);
+	}
 	return rc;
 }