SUNRPC,RPCSEC_GSS: fix krb5 sequence numbers.

Use a spinlock to ensure unique sequence numbers when creating krb5 gss tokens.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/gss_krb5.h

@@ -53,6 +53,8 @@ struct krb5_ctx {
 	struct xdr_netobj	mech_used;
 };
 
+extern spinlock_t krb5_seq_lock;
+
 #define KG_TOK_MIC_MSG    0x0101
 #define KG_TOK_WRAP_MSG   0x0201
 

net/sunrpc/auth_gss/gss_krb5_seal.c

@@ -70,6 +70,8 @@
 # define RPCDBG_FACILITY        RPCDBG_AUTH
 #endif
 
+spinlock_t krb5_seq_lock = SPIN_LOCK_UNLOCKED;
+
 u32
 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 		struct xdr_netobj *token)
@@ -80,6 +82,7 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 	struct xdr_netobj	md5cksum = {.len = 0, .data = cksumdata};
 	unsigned char		*ptr, *krb5_hdr, *msg_start;
 	s32			now;
+	u32			seq_send;
 
 	dprintk("RPC:     gss_krb5_seal\n");
 
@@ -134,12 +137,14 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 		BUG();
 	}
 
+	spin_lock(&krb5_seq_lock);
+	seq_send = ctx->seq_send++;
+	spin_unlock(&krb5_seq_lock);
+
 	if ((krb5_make_seq_num(ctx->seq, ctx->initiate ? 0 : 0xff,
-			       ctx->seq_send, krb5_hdr + 16, krb5_hdr + 8)))
+			       seq_send, krb5_hdr + 16, krb5_hdr + 8)))
 		goto out_err;
 
-	ctx->seq_send++;
-
 	return ((ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
 out_err:
 	return GSS_S_FAILURE;

net/sunrpc/auth_gss/gss_krb5_wrap.c

@@ -128,6 +128,7 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 	s32			now;
 	int			headlen;
 	struct page		**tmp_pages;
+	u32			seq_send;
 
 	dprintk("RPC:     gss_wrap_kerberos\n");
 
@@ -206,18 +207,20 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 		BUG();
 	}
 
+	spin_lock(&krb5_seq_lock);
+	seq_send = kctx->seq_send++;
+	spin_unlock(&krb5_seq_lock);
+
 	/* XXX would probably be more efficient to compute checksum
 	 * and encrypt at the same time: */
 	if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,
-			       kctx->seq_send, krb5_hdr + 16, krb5_hdr + 8)))
+			       seq_send, krb5_hdr + 16, krb5_hdr + 8)))
 		goto out_err;
 
 	if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,
 									pages))
 		goto out_err;
 
-	kctx->seq_send++;
-
 	return ((kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
 out_err:
 	return GSS_S_FAILURE;