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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>
wifi-calibration
J. Bruce Fields 2013-10-09 15:59:29 -04:00
parent b26ec9b11b
commit 5d6baef9ab
2 changed files with 8 additions and 6 deletions

View File

@ -150,7 +150,6 @@ gss_verify_mic_v2(struct krb5_ctx *ctx,
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 @@ gss_verify_mic_v2(struct krb5_ctx *ctx,
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;
}

View File

@ -489,7 +489,6 @@ static u32
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 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
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);