From 32ddd944a056c786f6acdd95ed29e994adc613a2 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 3 Jan 2017 12:30:11 -0500 Subject: [PATCH] nfsd: opt in to labeled nfs per export Currently turning on NFSv4.2 results in 4.2 clients suddenly seeing the individual file labels as they're set on the server. This is not what they've previously seen, and not appropriate in may cases. (In particular, if clients have heterogenous security policies then one client's labels may not even make sense to another.) Labeled NFS should be opted in only in those cases when the administrator knows it makes sense. It's helpful to be able to turn 4.2 on by default, and otherwise the protocol upgrade seems free of regressions. So, default labeled NFS to off and provide an export flag to reenable it. Users wanting labeled NFS support on an export will henceforth need to: - make sure 4.2 support is enabled on client and server (as before), and - upgrade the server nfs-utils to a version supporting the new "security_label" export flag. - set that "security_label" flag on the export. This is commit may be seen as a regression to anyone currently depending on security labels. We believe those cases are currently rare. Reported-by: tibbs@math.uh.edu Signed-off-by: J. Bruce Fields --- fs/nfsd/export.c | 1 + fs/nfsd/nfs4proc.c | 4 ++++ fs/nfsd/nfs4xdr.c | 5 ++++- include/uapi/linux/nfsd/export.h | 5 +++-- 4 files changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 43e109cc0ccc..e71f11b1a180 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -1102,6 +1102,7 @@ static struct flags { { NFSEXP_NOAUTHNLM, {"insecure_locks", ""}}, { NFSEXP_V4ROOT, {"v4root", ""}}, { NFSEXP_PNFS, {"pnfs", ""}}, + { NFSEXP_SECURITY_LABEL, {"security_label", ""}}, { 0, {"", ""}} }; diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 2d4eb47177d1..171f2d7ecfdd 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -95,11 +95,15 @@ check_attr_support(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, u32 *bmval, u32 *writable) { struct dentry *dentry = cstate->current_fh.fh_dentry; + struct svc_export *exp = cstate->current_fh.fh_export; if (!nfsd_attrs_supported(cstate->minorversion, bmval)) return nfserr_attrnotsupp; if ((bmval[0] & FATTR4_WORD0_ACL) && !IS_POSIXACL(d_inode(dentry))) return nfserr_attrnotsupp; + if ((bmval[2] & FATTR4_WORD2_SECURITY_LABEL) && + !(exp->ex_flags & NFSEXP_SECURITY_LABEL)) + return nfserr_attrnotsupp; if (writable && !bmval_is_subset(bmval, writable)) return nfserr_inval; if (writable && (bmval[2] & FATTR4_WORD2_MODE_UMASK) && diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 12cc6b29e78c..3cc190755958 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2417,8 +2417,11 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, #ifdef CONFIG_NFSD_V4_SECURITY_LABEL if ((bmval2 & FATTR4_WORD2_SECURITY_LABEL) || bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) { - err = security_inode_getsecctx(d_inode(dentry), + if (exp->ex_flags & NFSEXP_SECURITY_LABEL) + err = security_inode_getsecctx(d_inode(dentry), &context, &contextlen); + else + err = -EOPNOTSUPP; contextsupport = (err == 0); if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) { if (err == -EOPNOTSUPP) diff --git a/include/uapi/linux/nfsd/export.h b/include/uapi/linux/nfsd/export.h index 0df7bd5d2fb1..c3be256107c6 100644 --- a/include/uapi/linux/nfsd/export.h +++ b/include/uapi/linux/nfsd/export.h @@ -32,7 +32,8 @@ #define NFSEXP_ASYNC 0x0010 #define NFSEXP_GATHERED_WRITES 0x0020 #define NFSEXP_NOREADDIRPLUS 0x0040 -/* 80 100 currently unused */ +#define NFSEXP_SECURITY_LABEL 0x0080 +/* 0x100 currently unused */ #define NFSEXP_NOHIDE 0x0200 #define NFSEXP_NOSUBTREECHECK 0x0400 #define NFSEXP_NOAUTHNLM 0x0800 /* Don't authenticate NLM requests - just trust */ @@ -53,7 +54,7 @@ #define NFSEXP_PNFS 0x20000 /* All flags that we claim to support. (Note we don't support NOACL.) */ -#define NFSEXP_ALLFLAGS 0x3FE7F +#define NFSEXP_ALLFLAGS 0x3FEFF /* The flags that may vary depending on security flavor: */ #define NFSEXP_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \