On Wed, Oct 17, 2018 at 7:48 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote:
>
> We need to convert from little-endian before dong range checks on the
> ibpkey port numbers, otherwise we would be checking a wrong value.
>
> Fixes: 9fbb3112769a ("libsepol: Add ibpkey ocontext handling")
> Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
> ---
> libsepol/src/policydb.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
> index a6d76ca3..dc201e2f 100644
> --- a/libsepol/src/policydb.c
> +++ b/libsepol/src/policydb.c
> @@ -2830,15 +2830,21 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
> break;
> case OCON_IBPKEY:
> rc = next_entry(buf, fp, sizeof(uint32_t) * 4);
> - if (rc < 0 || buf[2] > 0xffff || buf[3] > 0xffff)
> + if (rc < 0)
> return -1;
>
> + c->u.ibpkey.low_pkey = le32_to_cpu(buf[2]);
> + c->u.ibpkey.high_pkey = le32_to_cpu(buf[3]);
Ahh you're assigning a 32 bit value to a 16 bit variable low|high_pkey. I think
you need to assign them to a uint32_t if you want to actually range check them.
> +
> + if (c->u.ibpkey.low_pkey > 0xffff ||
> + c->u.ibpkey.high_pkey > 0xffff)
> + return -1;
> +
> + /* we want c->u.ibpkey.subnet_prefix in network
> + * (big-endian) order, just memcpy it */
> memcpy(&c->u.ibpkey.subnet_prefix, buf,
> sizeof(c->u.ibpkey.subnet_prefix));
>
> - c->u.ibpkey.low_pkey = le32_to_cpu(buf[2]);
> - c->u.ibpkey.high_pkey = le32_to_cpu(buf[3]);
> -
> if (context_read_and_validate
> (&c->context[0], p, fp))
> return -1;
> --
> 2.17.2
>
See job: https://travis-ci.org/SELinuxProject/selinux/jobs/442750208
Build fail with gcc:
policydb.c:2839:31: error: comparison is always false due to limited
range of data type [-Werror=type-limits]
if (c->u.ibpkey.low_pkey > 0xffff ||
^
policydb.c:2840:31: error: comparison is always false due to limited
range of data type [-Werror=type-limits]
c->u.ibpkey.high_pkey > 0xffff)
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