[PATCH 16/17] NFSD: Server implementation of MAC Labeling

[Steve Dickson <SteveD@redhat.com>]

From: David Quigley <dpquigl@davequigley.com>

This patch adds the ability to encode and decode file labels on the server for
the purpose of sending them to the client and also to process label change
requests from the client.

Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
---
 fs/nfsd/nfs4proc.c |  41 ++++++++++++++++++
 fs/nfsd/nfs4xdr.c  | 123 +++++++++++++++++++++++++++++++++++++++++++++++++----
 fs/nfsd/nfsd.h     |  14 ++++++
 fs/nfsd/vfs.c      |  28 ++++++++++++
 fs/nfsd/vfs.h      |   2 +
 fs/nfsd/xdr4.h     |   3 ++
 6 files changed, 203 insertions(+), 8 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index ae73175..bb17589 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -42,6 +42,36 @@
 #include "current_stateid.h"
 #include "netns.h"
 
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+#include <linux/security.h>
+
+static inline void
+nfsd4_security_inode_setsecctx(struct svc_fh *resfh, struct nfs4_label *label, u32 *bmval)
+{
+	struct inode *inode = resfh->fh_dentry->d_inode;
+	int status;
+
+	mutex_lock(&inode->i_mutex);
+	status = security_inode_setsecctx(resfh->fh_dentry,
+		label->label, label->len);
+	mutex_unlock(&inode->i_mutex);
+
+	if (status)
+		/*
+		 * We should probably fail the whole open at this point,
+		 * but we've already created or opened the file, so it's 
+		 * too late; So this seems the least of evils:
+		 */
+		bmval[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+		
+	return;
+}
+#else 
+static inline void 
+nfsd4_security_inode_setsecctx(struct svc_fh *resfh, struct nfs4_label *label, u32 *bmval)
+{ }
+#endif
+
 #define NFSDDBG_FACILITY		NFSDDBG_PROC
 
 static u32 nfsd_attrmask[] = {
@@ -230,6 +260,9 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o
 					(u32 *)open->op_verf.data,
 					&open->op_truncate, &open->op_created);
 
+		if (!status && open->op_label != NULL) 
+			nfsd4_security_inode_setsecctx(resfh, open->op_label, open->op_bmval);
+
 		/*
 		 * Following rfc 3530 14.2.16, use the returned bitmask
 		 * to indicate which attributes we used to store the
@@ -599,6 +632,9 @@ nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (status)
 		goto out;
 
+	if (create->cr_label != NULL)
+		nfsd4_security_inode_setsecctx(&resfh, create->cr_label, create->cr_bmval);
+
 	if (create->cr_acl != NULL)
 		do_set_nfs4_acl(rqstp, &resfh, create->cr_acl,
 				create->cr_bmval);
@@ -888,6 +924,11 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 					    setattr->sa_acl);
 	if (status)
 		goto out;
+	if (setattr->sa_label != NULL)
+		status = nfsd4_set_nfs4_label(rqstp, &cstate->current_fh,
+				setattr->sa_label);
+	if (status)
+		goto out;
 	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
 				0, (time_t)0);
 out:
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b38de7a..1a8b347 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -55,6 +55,11 @@
 #include "cache.h"
 #include "netns.h"
 
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+#include <linux/security.h>
+#endif
+
+
 #define NFSDDBG_FACILITY		NFSDDBG_XDR
 
 /*
@@ -79,6 +84,23 @@ check_filename(char *str, int len)
 			return nfserr_badname;
 	return 0;
 }
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+static __be32
+nfsd4_label_alloc(u32 len, struct nfs4_label **label)
+{
+	if (len > NFS4_MAXLABELLEN)
+		return nfserr_badlabel;
+
+	*label = kzalloc(len + sizeof(struct nfs4_label) + 1, GFP_KERNEL);
+	if (*label == NULL)
+		return nfserr_jukebox;
+
+	(*label)->label = (char *)(*label + 1);
+	(*label)->len = len;
+
+	return nfs_ok;
+}
+#endif
 
 #define DECODE_HEAD				\
 	__be32 *p;				\
@@ -242,7 +264,8 @@ nfsd4_decode_bitmap(struct nfsd4_compoundargs *argp, u32 *bmval)
 
 static __be32
 nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
-		   struct iattr *iattr, struct nfs4_acl **acl)
+		   struct iattr *iattr, struct nfs4_acl **acl,
+		   struct nfs4_label **label)
 {
 	int expected_len, len = 0;
 	u32 dummy32;
@@ -386,6 +409,38 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 			goto xdr_error;
 		}
 	}
+
+	*label = NULL;
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
+		uint32_t pi;
+		uint32_t lfs;
+
+		READ_BUF(4);
+		len += 4;
+		READ32(lfs);
+		READ_BUF(4);
+		len += 4;
+		READ32(pi);
+		READ_BUF(4);
+		len += 4;
+		READ32(dummy32);
+		READ_BUF(dummy32);
+		len += (XDR_QUADLEN(dummy32) << 2);
+		READMEM(buf, dummy32);
+
+		if ((status = nfsd4_label_alloc(dummy32, label)))
+			return status;
+
+		memcpy((*label)->label, buf, (*label)->len);
+		((*label)->label)[(*label)->len] = '\0';
+		(*label)->pi = pi;
+		(*label)->lfs = lfs;
+
+		defer_free(argp, kfree, *label);
+	}
+#endif
+
 	if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
 	    || bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
 	    || bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2)
@@ -582,7 +637,7 @@ nfsd4_decode_create(struct nfsd4_compoundargs *argp, struct nfsd4_create *create
 		return status;
 
 	status = nfsd4_decode_fattr(argp, create->cr_bmval, &create->cr_iattr,
-				    &create->cr_acl);
+				    &create->cr_acl, &create->cr_label);
 	if (status)
 		goto out;
 
@@ -832,7 +887,7 @@ nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 		case NFS4_CREATE_UNCHECKED:
 		case NFS4_CREATE_GUARDED:
 			status = nfsd4_decode_fattr(argp, open->op_bmval,
-				&open->op_iattr, &open->op_acl);
+				&open->op_iattr, &open->op_acl, &open->op_label);
 			if (status)
 				goto out;
 			break;
@@ -846,7 +901,7 @@ nfsd4_decode_open(struct nfsd4_compoundargs *argp, struct nfsd4_open *open)
 			READ_BUF(NFS4_VERIFIER_SIZE);
 			COPYMEM(open->op_verf.data, NFS4_VERIFIER_SIZE);
 			status = nfsd4_decode_fattr(argp, open->op_bmval,
-				&open->op_iattr, &open->op_acl);
+				&open->op_iattr, &open->op_acl, &open->op_label);
 			if (status)
 				goto out;
 			break;
@@ -1068,7 +1123,7 @@ nfsd4_decode_setattr(struct nfsd4_compoundargs *argp, struct nfsd4_setattr *seta
 	if (status)
 		return status;
 	return nfsd4_decode_fattr(argp, setattr->sa_bmval, &setattr->sa_iattr,
-				  &setattr->sa_acl);
+				  &setattr->sa_acl, &setattr->sa_label);
 }
 
 static __be32
@@ -1989,6 +2044,50 @@ nfsd4_encode_aclname(struct svc_rqst *rqstp, struct nfs4_ace *ace,
 			      FATTR4_WORD0_RDATTR_ERROR)
 #define WORD1_ABSENT_FS_ATTRS FATTR4_WORD1_MOUNTED_ON_FILEID
 
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+static inline __be32
+nfsd4_encode_security_label(struct svc_rqst *rqstp, struct dentry *dentry, __be32 **pp, int *buflen)
+{
+	void *context;
+	int err;
+	int len;
+	uint32_t pi = 0;
+	uint32_t lfs = 0;
+	__be32 *p = *pp;
+
+	err = 0;
+	(void)security_inode_getsecctx(dentry->d_inode, &context, &len);
+	if (len < 0)
+		return nfserrno(len);
+
+	if (*buflen < ((XDR_QUADLEN(len) << 2) + 4 + 4 + 4)) {
+		err = nfserr_resource;
+		goto out;
+	}
+
+	/*
+	 * For now we use a 0 here to indicate the null translation; in
+	 * the future we may place a call to translation code here.
+	 */
+	if ((*buflen -= 8) < 0)
+		return nfserr_resource;
+
+	WRITE32(lfs);	
+	WRITE32(pi);
+	p = xdr_encode_opaque(p, context, len);
+	*buflen -= (XDR_QUADLEN(len) << 2) + 4;
+
+	*pp = p;
+out:
+	security_release_secctx(context, len);
+	return err;
+}
+#else
+static inline __be32
+nfsd4_encode_security_label(struct svc_rqst *rqstp, struct dentry *dentry, __be32 **pp, int *buflen)
+{ return 0; }
+#endif
+
 static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *rdattr_err)
 {
 	/* As per referral draft:  */
@@ -2439,6 +2538,12 @@ out_acl:
 			get_parent_attributes(exp, &stat);
 		WRITE64(stat.ino);
 	}
+	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
+		status = nfsd4_encode_security_label(rqstp, dentry,
+				&p, &buflen);
+		if (status)
+			goto out;
+	}
 	if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
 		WRITE32(3);
 		WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD0);
@@ -3226,16 +3331,18 @@ nfsd4_encode_setattr(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 {
 	__be32 *p;
 
-	RESERVE_SPACE(12);
+	RESERVE_SPACE(16);
 	if (nfserr) {
-		WRITE32(2);
+		WRITE32(3);
+		WRITE32(0);
 		WRITE32(0);
 		WRITE32(0);
 	}
 	else {
-		WRITE32(2);
+		WRITE32(3);
 		WRITE32(setattr->sa_bmval[0]);
 		WRITE32(setattr->sa_bmval[1]);
+		WRITE32(setattr->sa_bmval[2]);
 	}
 	ADJUST_ARGS();
 	return nfserr;
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 15e7e1d..875e0d4 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -328,6 +328,13 @@ void		nfsd_lockd_shutdown(void);
 #define NFSD4_1_SUPPORTED_ATTRS_WORD2 \
 	(NFSD4_SUPPORTED_ATTRS_WORD2 | FATTR4_WORD2_SUPPATTR_EXCLCREAT)
 
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+#define NFSD4_2_SUPPORTED_ATTRS_WORD2 \
+	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | FATTR4_WORD2_SECURITY_LABEL)
+#else
+#define NFSD4_2_SUPPORTED_ATTRS_WORD2 0
+#endif
+
 static inline u32 nfsd_suppattrs0(u32 minorversion)
 {
 	return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD0
@@ -342,6 +349,9 @@ static inline u32 nfsd_suppattrs1(u32 minorversion)
 
 static inline u32 nfsd_suppattrs2(u32 minorversion)
 {
+	if (minorversion == 2)
+		return NFSD4_2_SUPPORTED_ATTRS_WORD2;
+
 	return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD2
 			    : NFSD4_SUPPORTED_ATTRS_WORD2;
 }
@@ -356,7 +366,11 @@ static inline u32 nfsd_suppattrs2(u32 minorversion)
 #define NFSD_WRITEABLE_ATTRS_WORD1 \
 	(FATTR4_WORD1_MODE | FATTR4_WORD1_OWNER | FATTR4_WORD1_OWNER_GROUP \
 	| FATTR4_WORD1_TIME_ACCESS_SET | FATTR4_WORD1_TIME_MODIFY_SET)
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+#define NFSD_WRITEABLE_ATTRS_WORD2 FATTR4_WORD2_SECURITY_LABEL
+#else
 #define NFSD_WRITEABLE_ATTRS_WORD2 0
+#endif
 
 #define NFSD_SUPPATTR_EXCLCREAT_WORD0 \
 	NFSD_WRITEABLE_ATTRS_WORD0
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 2b2e239..96f9a82 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -28,6 +28,7 @@
 #include <asm/uaccess.h>
 #include <linux/exportfs.h>
 #include <linux/writeback.h>
+#include <linux/security.h>
 
 #ifdef CONFIG_NFSD_V3
 #include "xdr3.h"
@@ -621,6 +622,33 @@ int nfsd4_is_junction(struct dentry *dentry)
 		return 0;
 	return 1;
 }
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
+		struct nfs4_label *label)
+{
+	__be32 error;
+	int host_error;
+	struct dentry *dentry;
+
+	error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
+	if (error)
+		return error;
+
+	dentry = fhp->fh_dentry;
+
+	mutex_lock(&dentry->d_inode->i_mutex);
+	host_error = security_inode_setsecctx(dentry, label->label, label->len);
+	mutex_unlock(&dentry->d_inode->i_mutex);
+	return nfserrno(host_error);
+}
+#else
+__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
+		struct nfs4_label *label)
+{
+	return nfserr_notsupp;
+}
+#endif
+
 #endif /* defined(CONFIG_NFSD_V4) */
 
 #ifdef CONFIG_NFSD_V3
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 5b58941..a9d6f0f 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -56,6 +56,8 @@ int nfsd_mountpoint(struct dentry *, struct svc_export *);
 __be32          nfsd4_set_nfs4_acl(struct svc_rqst *, struct svc_fh *,
                     struct nfs4_acl *);
 int             nfsd4_get_nfs4_acl(struct svc_rqst *, struct dentry *, struct nfs4_acl **);
+__be32          nfsd4_set_nfs4_label(struct svc_rqst *, struct svc_fh *,
+		    struct nfs4_label *);
 #endif /* CONFIG_NFSD_V4 */
 __be32		nfsd_create(struct svc_rqst *, struct svc_fh *,
 				char *name, int len, struct iattr *attrs,
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 546f898..132a671 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -118,6 +118,7 @@ struct nfsd4_create {
 	struct iattr	cr_iattr;           /* request */
 	struct nfsd4_change_info  cr_cinfo; /* response */
 	struct nfs4_acl *cr_acl;
+	struct nfs4_label *cr_label;
 };
 #define cr_linklen	u.link.namelen
 #define cr_linkname	u.link.name
@@ -246,6 +247,7 @@ struct nfsd4_open {
 	struct nfs4_file *op_file;          /* used during processing */
 	struct nfs4_ol_stateid *op_stp;	    /* used during processing */
 	struct nfs4_acl *op_acl;
+	struct nfs4_label *op_label;
 };
 #define op_iattr	iattr
 
@@ -330,6 +332,7 @@ struct nfsd4_setattr {
 	u32		sa_bmval[3];        /* request */
 	struct iattr	sa_iattr;           /* request */
 	struct nfs4_acl *sa_acl;
+	struct nfs4_label *sa_label;
 };
 
 struct nfsd4_setclientid {
-- 
1.8.1.4