gss_krb5: document that we ignore sequence number
A couple times recently somebody has noticed that we're ignoring a
sequence number here and wondered whether there's a bug.
In fact, there's not. Thanks to Andy Adamson for pointing out a useful
explanation in rfc 2203. Add comments citing that rfc, and remove
"seqnum" to prevent static checkers complaining about unused variables.
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c
index 6cd930f..6c981dd 100644
--- a/net/sunrpc/auth_gss/gss_krb5_unseal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c
@@ -150,7 +150,6 @@
struct xdr_netobj cksumobj = {.len = sizeof(cksumdata),
.data = cksumdata};
s32 now;
- u64 seqnum;
u8 *ptr = read_token->data;
u8 *cksumkey;
u8 flags;
@@ -197,9 +196,10 @@
if (now > ctx->endtime)
return GSS_S_CONTEXT_EXPIRED;
- /* do sequencing checks */
-
- seqnum = be64_to_cpup((__be64 *)ptr + 8);
+ /*
+ * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
+ * doesn't want it checked; see page 6 of rfc 2203.
+ */
return GSS_S_COMPLETE;
}
diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index 1da52d1..5040a46 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -489,7 +489,6 @@
gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
{
s32 now;
- u64 seqnum;
u8 *ptr;
u8 flags = 0x00;
u16 ec, rrc;
@@ -525,7 +524,10 @@
ec = be16_to_cpup((__be16 *)(ptr + 4));
rrc = be16_to_cpup((__be16 *)(ptr + 6));
- seqnum = be64_to_cpup((__be64 *)(ptr + 8));
+ /*
+ * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
+ * doesn't want it checked; see page 6 of rfc 2203.
+ */
if (rrc != 0)
rotate_left(offset + 16, buf, rrc);