On Sun, Oct 10, 2021 at 4:40 PM Nicolas Iooss <nicolas.iooss@xxxxxxx> wrote:
>
> On Fri, Oct 8, 2021 at 11:10 PM James Carter <jwcart2@xxxxxxxxx> wrote:
> >
> > An expression of the form "1 << x" is undefined if x == 31 because
> > the "1" is an int and cannot be left shifted by 31.
> >
> > Instead, use "UINT32_C(1) << x" which will be an unsigned int of
> > at least 32 bits.
> >
> > This bug was found by the secilc-fuzzer.
> >
> > Signed-off-by: James Carter <jwcart2@xxxxxxxxx>
> > ---
> > libsepol/cil/src/cil_binary.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/libsepol/cil/src/cil_binary.c b/libsepol/cil/src/cil_binary.c
> > index ec5f01e5..34dc63c7 100644
> > --- a/libsepol/cil/src/cil_binary.c
> > +++ b/libsepol/cil/src/cil_binary.c
> > @@ -1225,7 +1225,7 @@ int __perm_str_to_datum(char *perm_str, class_datum_t *sepol_class, uint32_t *da
> > goto exit;
> > }
> > }
> > - *datum |= 1 << (sepol_perm->s.value - 1);
> > + *datum |= UINT32_C(1) << (sepol_perm->s.value - 1);
> >
> > return SEPOL_OK;
> >
> > @@ -1523,7 +1523,7 @@ int cil_avrule_to_policydb(policydb_t *pdb, const struct cil_db *db, struct cil_
> > /* index of the u32 containing the permission */
> > #define XPERM_IDX(x) (x >> 5)
> > /* set bits 0 through x-1 within the u32 */
> > -#define XPERM_SETBITS(x) ((1U << (x & 0x1f)) - 1)
> > +#define XPERM_SETBITS(x) (UINT32_C(1) << (x & 0x1f)) - 1)
>
> There is a missing parenthesis here: "UINT32_C(1)" -> "(UINT32_C(1)"
>
> Other than this, the 4 patches look good to me:
>
> Acked-by: Nicolas Iooss <nicolas.iooss@xxxxxxx>
>
I fixed the missing parenthesis and merged these patches.
Thanks,
Jim
> Thanks!
> Nicolas
>
> > /* low value for this u32 */
> > #define XPERM_LOW(x) (x << 5)
> > /* high value for this u32 */
> > @@ -4760,7 +4760,7 @@ static struct cil_list *cil_classperms_from_sepol(policydb_t *pdb, uint16_t clas
> > cil_list_init(&cp->perms, CIL_PERM);
> > for (i = 0; i < sepol_class->permissions.nprim; i++) {
> > struct cil_perm *perm;
> > - if ((data & (1 << i)) == 0) continue;
> > + if ((data & (UINT32_C(1) << i)) == 0) continue;
> > perm = perm_value_to_cil[class][i+1];
> > if (!perm) goto exit;
> > cil_list_append(cp->perms, CIL_PERM, perm);
> > --
> > 2.31.1
> >
>
