Attachment 231735 Details for Bug 261291 – Workaround ESXi's CREATE_SESSION sequence_id bug

[patch] Workaround ESXi's CREATE_SESSION sequence_id bug

0001-nfs-Optionally-workaround-a-bug-in-the-VMWare-ESXi-N.patch (text/plain), 3.85 KB, created by Alan Somers on 2022-02-10 23:28:46 UTC

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Creator: Alan Somers

Created: 2022-02-10 23:28:46 UTC

Size: 3.85 KB

patch

obsolete

>From 919a9566c32be82c52bb12b748702198e3509fb8 Mon Sep 17 00:00:00 2001
>From: Alan Somers <asomers@axcient.com>
>Date: Wed, 9 Feb 2022 17:32:30 +0000
>Subject: [PATCH] nfs: Optionally workaround a bug in the VMWare ESXi NFS 4.1
> client
>
>The ESXi NFS 4.1 client, for reasons of its own, will send a
>DESTROY_SESSION/CREATE_SESSION if it loses connectivity to the server
>for more than a few seconds.  But it sets the wrong value for
>csa_sequence.  RFC 5661 section 18.36.4 specifies that the
>CREATE_SESSION's csa_sequence should be the same as the preceding
>EXCHANGE_ID result's eir_sequenceid.  But ESX uses something else
>instead, leading to the server returning NFSERR_SEQMISORDERED and the
>client retrying, ad infinitum.
>
>This commit adds a vfs.nfsd.esx_seqid_hack sysctl.  When set, if the
>client's nii_domain is set to "vmware.com" during EXCHANGE_ID, then the
>server will ignore the value of csa_sequence during a subsequent
>CREATE_SESSION.
>
>CEWIN-1927
>
>PR:	261291
>---
> sys/fs/nfs/nfsrvstate.h          |  1 +
> sys/fs/nfsserver/nfs_nfsdserv.c  | 25 +++++++++++++++++++++++++
> sys/fs/nfsserver/nfs_nfsdstate.c |  8 +++++++-
> 3 files changed, 33 insertions(+), 1 deletion(-)
>
>diff --git a/sys/fs/nfs/nfsrvstate.h b/sys/fs/nfs/nfsrvstate.h
>index 427d5b132281..7991214ce1ee 100644
>--- a/sys/fs/nfs/nfsrvstate.h
>+++ b/sys/fs/nfs/nfsrvstate.h
>@@ -116,6 +116,7 @@ struct nfsclient {
> 	struct nfssockreq lc_req;		/* Callback info */
> 	u_int32_t	lc_flags;		/* LCL_ flag bits */
> 	u_char		lc_verf[NFSX_VERF];	 /* client verifier */
>+	bool		lc_is_vmware;		/* VMWare.com NFS client? */
> 	u_char		lc_id[1];		/* Malloc'd correct size */
> };
> 
>diff --git a/sys/fs/nfsserver/nfs_nfsdserv.c b/sys/fs/nfsserver/nfs_nfsdserv.c
>index ab02df2c4a46..bfff670ba4b7 100644
>--- a/sys/fs/nfsserver/nfs_nfsdserv.c
>+++ b/sys/fs/nfsserver/nfs_nfsdserv.c
>@@ -4362,6 +4362,31 @@ nfsrvd_exchangeid(struct nfsrv_descript *nd, __unused int isdgram,
> 		goto nfsmout;
> 	}
> 
>+	/*
>+	 * Check if the client implementation is VMWare ESX
>+	 * XXX RFC 5661 section 18.35.3 explicitly tells us not to take any
>+	 * action based on this, but we've got a bug to workaround.
>+	 */
>+	clp->lc_is_vmware = false;
>+	tl = nfsm_dissect(nd, sizeof(uint32_t));
>+	if (!tl)
>+		goto no_implname;
>+	uint32_t eia_client_impl_id = fxdr_unsigned(uint32_t, *tl);
>+	if (eia_client_impl_id == 0)
>+		goto no_implname;
>+	tl = nfsm_dissect(nd, sizeof(uint32_t));
>+	if (!tl)
>+		goto no_implname;
>+	uint32_t nii_domain_len = fxdr_unsigned(uint32_t, *tl);
>+	if (nii_domain_len <= 0)
>+		goto no_implname;
>+	s = nfsm_dissect(nd, nii_domain_len * sizeof(char));
>+	if (!s)
>+		goto no_implname;
>+	if (strncmp(s, "vmware.com", nii_domain_len) == 0)
>+		clp->lc_is_vmware = true;
>+
>+no_implname:
> 	/*
> 	 * nfsrv_setclient() does the actual work of adding it to the
> 	 * client list. If there is no error, the structure has been
>diff --git a/sys/fs/nfsserver/nfs_nfsdstate.c b/sys/fs/nfsserver/nfs_nfsdstate.c
>index 47592087be4a..15f345bf456e 100644
>--- a/sys/fs/nfsserver/nfs_nfsdstate.c
>+++ b/sys/fs/nfsserver/nfs_nfsdstate.c
>@@ -115,6 +115,11 @@ SYSCTL_INT(_vfs_nfsd, OID_AUTO, flexlinuxhack, CTLFLAG_RW,
>     &nfsrv_flexlinuxhack, 0,
>     "For Linux clients, hack around Flex File Layout bug");
> 
>+int	nfsrv_esx_seqid_hack = 0;
>+SYSCTL_INT(_vfs_nfsd, OID_AUTO, esx_seqid_hack, CTLFLAG_RW,
>+    &nfsrv_esx_seqid_hack, 0,
>+    "Disregard a CREATE_SESSION request's sequence id for VMWare ESXi clients.");
>+
> /*
>  * Hash lists for nfs V4.
>  */
>@@ -677,7 +682,8 @@ nfsrv_getclient(nfsquad_t clientid, int opflags, struct nfsclient **clpp,
> 	 */
> 	if (opflags & CLOPS_CONFIRM) {
> 		if ((nd->nd_flag & ND_NFSV41) != 0 &&
>-		     clp->lc_confirm.lval[0] != confirm.lval[0])
>+		    (!(nfsrv_esx_seqid_hack && clp->lc_is_vmware) &&
>+		     (clp->lc_confirm.lval[0] != confirm.lval[0])))
> 			error = NFSERR_SEQMISORDERED;
> 		else if ((nd->nd_flag & ND_NFSV41) == 0 &&
> 		     clp->lc_confirm.qval != confirm.qval)
>-- 
>2.35.1
>

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Attachments on bug 261291: 231662 | 231733 | 231735