On Mon, Mar 11, 2024 at 9:48 AM Christian Göttsche
<cgzones@xxxxxxxxxxxxxx> wrote:
>
> On Mon, 11 Mar 2024 at 13:48, James Carter <jwcart2@xxxxxxxxx> wrote:
> >
> > The function sepol_av_to_string() returns a list of permissions
> > with a space at the beginning. This fits the normal formating of
> > permisisons for a policy.conf policy which uses a format of
> > "{ p1 p2 ... pn }", but not the formating for a CIL policy which uses
> > a format of "(p1 p2 ... pn)". Both kernel_to_cil and module_to_cil
> > skip the space by using "perms+1", but this is a problem if there
> > are no permissions because sepol_av_to_string() returns '\0'.
> >
> > In kernel_to_cil and module_to_cil, check for the permission string
> > being '\0' and return an error if it is.
> >
> > Reported-by: oss-fuzz (issue 67276)
> > Signed-off-by: James Carter <jwcart2@xxxxxxxxx>
> > ---
> > libsepol/src/kernel_to_cil.c | 11 +++++++++++
> > libsepol/src/module_to_cil.c | 12 ++++++++++++
>
> I think there are also two occurrences in libsepol/src/kernel_to_conf.c.
>
> Also: s/permisisons/permissions/
>
Thanks, I was thinking that it was just a CIL problem.
Jim
> > 2 files changed, 23 insertions(+)
> >
> > diff --git a/libsepol/src/kernel_to_cil.c b/libsepol/src/kernel_to_cil.c
> > index a081915e..e20ba4af 100644
> > --- a/libsepol/src/kernel_to_cil.c
> > +++ b/libsepol/src/kernel_to_cil.c
> > @@ -302,6 +302,12 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey,
> > rc = -1;
> > goto exit;
> > }
> > + if (*perms == '\0') {
> > + ERR(NULL, "No permisisons in permission string");
> > + free(perms);
> > + rc = -1;
> > + goto exit;
> > + }
> >
> > if (is_mls) {
> > key_word = "mlsconstrain";
> > @@ -1775,6 +1781,11 @@ static char *avtab_node_to_str(struct policydb *pdb, avtab_key_t *key, avtab_dat
> > ERR(NULL, "Failed to generate permission string");
> > goto exit;
> > }
> > + if (*perms == '\0') {
> > + ERR(NULL, "No permisisons in permission string");
> > + free(perms);
> > + goto exit;
> > + }
> > rule = create_str("(%s %s %s (%s (%s)))",
> > flavor, src, tgt, class, perms+1);
> > free(perms);
> > diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
> > index 6699a46b..3b3480bf 100644
> > --- a/libsepol/src/module_to_cil.c
> > +++ b/libsepol/src/module_to_cil.c
> > @@ -593,6 +593,12 @@ static int avrule_to_cil(int indent, struct policydb *pdb, uint32_t type, const
> > rc = -1;
> > goto exit;
> > }
> > + if (*perms == '\0') {
> > + ERR(NULL, "No permissions in permission string");
> > + free(perms);
> > + rc = -1;
> > + goto exit;
> > + }
> > cil_println(indent, "(%s %s %s (%s (%s)))",
> > rule, src, tgt,
> > pdb->p_class_val_to_name[classperm->tclass - 1],
> > @@ -1973,6 +1979,12 @@ static int constraints_to_cil(int indent, struct policydb *pdb, char *classkey,
> > rc = -1;
> > goto exit;
> > }
> > + if (*perms == '\0') {
> > + ERR(NULL, "No permissions in permission string");
> > + free(perms);
> > + rc = -1;
> > + goto exit;
> > + }
> > cil_println(indent, "(%sconstrain (%s (%s)) %s)", mls, classkey, perms + 1, expr);
> > free(perms);
> > } else {
> > --
> > 2.44.0
> >
> >
