From 5d6baef9ab52d0d02b3106d8ccd1b05ec628e027 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 9 Oct 2013 15:59:29 -0400 Subject: [PATCH] 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 Signed-off-by: J. Bruce Fields --- net/sunrpc/auth_gss/gss_krb5_unseal.c | 8 ++++---- net/sunrpc/auth_gss/gss_krb5_wrap.c | 6 ++++-- 2 files changed, 8 insertions(+), 6 deletions(-) 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 @@ 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; } 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 @@ 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); -- 2.7.4