rpc: comment on linux_cred encoding, treat all as unsigned

The encoding of linux creds is a bit confusing.

Also: I think in practice it doesn't really matter whether we treat any
of these things as signed or unsigned, but unsigned seems more
straightforward: uid_t/gid_t are unsigned and it simplifies the ngroups
overflow check.

Tested-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2013-08-23 11:17:53 -04:00
parent 778e512bb1
commit 6a36978e69

View File

@ -166,14 +166,15 @@ static int dummy_dec_opt_array(struct xdr_stream *xdr,
return 0;
}
static int get_s32(struct xdr_stream *xdr, s32 *res)
static int get_host_u32(struct xdr_stream *xdr, u32 *res)
{
__be32 *p;
p = xdr_inline_decode(xdr, 4);
if (!p)
return -EINVAL;
memcpy(res, p, sizeof(s32));
/* Contents of linux creds are all host-endian: */
memcpy(res, p, sizeof(u32));
return 0;
}
@ -182,8 +183,9 @@ static int gssx_dec_linux_creds(struct xdr_stream *xdr,
{
u32 length;
__be32 *p;
s32 tmp;
int N, i, err;
u32 tmp;
u32 N;
int i, err;
p = xdr_inline_decode(xdr, 4);
if (unlikely(p == NULL))
@ -195,19 +197,19 @@ static int gssx_dec_linux_creds(struct xdr_stream *xdr,
return -ENOSPC;
/* uid */
err = get_s32(xdr, &tmp);
err = get_host_u32(xdr, &tmp);
if (err)
return err;
creds->cr_uid = make_kuid(&init_user_ns, tmp);
/* gid */
err = get_s32(xdr, &tmp);
err = get_host_u32(xdr, &tmp);
if (err)
return err;
creds->cr_gid = make_kgid(&init_user_ns, tmp);
/* number of additional gid's */
err = get_s32(xdr, &tmp);
err = get_host_u32(xdr, &tmp);
if (err)
return err;
N = tmp;
@ -220,7 +222,7 @@ static int gssx_dec_linux_creds(struct xdr_stream *xdr,
/* gid's */
for (i = 0; i < N; i++) {
kgid_t kgid;
err = get_s32(xdr, &tmp);
err = get_host_u32(xdr, &tmp);
if (err)
goto out_free_groups;
err = -EINVAL;