[ 46/49] rpc: comment on linux_cred encoding, treat all as unsigned

Greg Kroah-Hartman
2013-09-29T19:50:30Z

From: "J. Bruce Fields" <bfields@redhat.com>

commit 6a36978e6931e6601be586eb313375335f2cfaa3 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/sunrpc/auth_gss/gss_rpc_xdr.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

--- a/net/sunrpc/auth_gss/gss_rpc_xdr.c
+++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c
@@ -166,14 +166,15 @@ static int dummy_dec_opt_array(struct xd
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 x
{
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 x
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 x
/* 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;