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>
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
>
