NFSD: Server implementation of MAC Labeling
Implement labeled NFS on the server: encoding and decoding, and writing
and reading, of file labels.
Enabled with CONFIG_NFSD_V4_SECURITY_LABEL.
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>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index 430b687..dc8f1ef 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -81,6 +81,22 @@
If unsure, say N.
+config NFSD_V4_SECURITY_LABEL
+ bool "Provide Security Label support for NFSv4 server"
+ depends on NFSD_V4 && SECURITY
+ help
+
+ Say Y here if you want enable fine-grained security label attribute
+ support for NFS version 4. Security labels allow security modules like
+ SELinux and Smack to label files to facilitate enforcement of their policies.
+ Without this an NFSv4 mount will have the same label on each file.
+
+ If you do not wish to enable fine-grained security labels SELinux or
+ Smack policies on NFSv4 files, say N.
+
+ WARNING: there is still a chance of backwards-incompatible protocol changes.
+ For now we recommend "Y" only for developers and testers."
+
config NFSD_FAULT_INJECTION
bool "NFS server manual fault injection"
depends on NFSD_V4 && DEBUG_KERNEL
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 27d74a2..1a1ff24 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 xdr_netobj *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->data, label->len);
+ mutex_unlock(&inode->i_mutex);
+
+ if (status)
+ /*
+ * XXX: We should really fail the whole open, but we may
+ * already have created a new file, so it may be too
+ * late. For now 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 xdr_netobj *label, u32 *bmval)
+{ }
+#endif
+
#define NFSDDBG_FACILITY NFSDDBG_PROC
static u32 nfsd_attrmask[] = {
@@ -239,6 +269,9 @@
(u32 *)open->op_verf.data,
&open->op_truncate, &open->op_created);
+ if (!status && open->op_label.len)
+ 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
@@ -637,6 +670,9 @@
if (status)
goto out;
+ if (create->cr_label.len)
+ 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);
@@ -916,6 +952,11 @@
setattr->sa_acl);
if (status)
goto out;
+ if (setattr->sa_label.len)
+ 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 9aeacdd..dfca512 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
/*
@@ -242,7 +247,8 @@
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 xdr_netobj *label)
{
int expected_len, len = 0;
u32 dummy32;
@@ -380,6 +386,32 @@
goto xdr_error;
}
}
+
+ label->len = 0;
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+ if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
+ READ_BUF(4);
+ len += 4;
+ READ32(dummy32); /* lfs: we don't use it */
+ READ_BUF(4);
+ len += 4;
+ READ32(dummy32); /* pi: we don't use it either */
+ READ_BUF(4);
+ len += 4;
+ READ32(dummy32);
+ READ_BUF(dummy32);
+ if (dummy32 > NFSD4_MAX_SEC_LABEL_LEN)
+ return nfserr_badlabel;
+ len += (XDR_QUADLEN(dummy32) << 2);
+ READMEM(buf, dummy32);
+ label->data = kzalloc(dummy32 + 1, GFP_KERNEL);
+ if (!label->data)
+ return nfserr_jukebox;
+ defer_free(argp, kfree, label->data);
+ memcpy(label->data, buf, dummy32);
+ }
+#endif
+
if (bmval[0] & ~NFSD_WRITEABLE_ATTRS_WORD0
|| bmval[1] & ~NFSD_WRITEABLE_ATTRS_WORD1
|| bmval[2] & ~NFSD_WRITEABLE_ATTRS_WORD2)
@@ -576,7 +608,7 @@
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;
@@ -827,7 +859,7 @@
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;
@@ -841,7 +873,7 @@
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;
@@ -1063,7 +1095,7 @@
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
@@ -1954,6 +1986,36 @@
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, void *context, int len, __be32 **pp, int *buflen)
+{
+ __be32 *p = *pp;
+
+ if (*buflen < ((XDR_QUADLEN(len) << 2) + 4 + 4 + 4))
+ return nfserr_resource;
+
+ /*
+ * 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(0); /* lfs */
+ WRITE32(0); /* pi */
+ p = xdr_encode_opaque(p, context, len);
+ *buflen -= (XDR_QUADLEN(len) << 2) + 4;
+
+ *pp = p;
+ return 0;
+}
+#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: */
@@ -2013,6 +2075,9 @@
int err;
int aclsupport = 0;
struct nfs4_acl *acl = NULL;
+ void *context = NULL;
+ int contextlen;
+ bool contextsupport = false;
struct nfsd4_compoundres *resp = rqstp->rq_resp;
u32 minorversion = resp->cstate.minorversion;
struct path path = {
@@ -2066,6 +2131,21 @@
}
}
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+ if ((bmval[2] & FATTR4_WORD2_SECURITY_LABEL) ||
+ bmval[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
+ err = security_inode_getsecctx(dentry->d_inode,
+ &context, &contextlen);
+ contextsupport = (err == 0);
+ if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
+ if (err == -EOPNOTSUPP)
+ bmval2 &= ~FATTR4_WORD2_SECURITY_LABEL;
+ else if (err)
+ goto out_nfserr;
+ }
+ }
+#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
+
if (bmval2) {
if ((buflen -= 16) < 0)
goto out_resource;
@@ -2094,6 +2174,8 @@
if (!aclsupport)
word0 &= ~FATTR4_WORD0_ACL;
+ if (!contextsupport)
+ word2 &= ~FATTR4_WORD2_SECURITY_LABEL;
if (!word2) {
if ((buflen -= 12) < 0)
goto out_resource;
@@ -2401,6 +2483,12 @@
get_parent_attributes(exp, &stat);
WRITE64(stat.ino);
}
+ if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
+ status = nfsd4_encode_security_label(rqstp, context,
+ contextlen, &p, &buflen);
+ if (status)
+ goto out;
+ }
if (bmval2 & FATTR4_WORD2_SUPPATTR_EXCLCREAT) {
WRITE32(3);
WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD0);
@@ -2413,6 +2501,8 @@
status = nfs_ok;
out:
+ if (context)
+ security_release_secctx(context, contextlen);
kfree(acl);
if (fhp == &tempfh)
fh_put(&tempfh);
@@ -3177,16 +3267,18 @@
{
__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..2bbd94e 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -328,6 +328,13 @@
#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
@@ -342,8 +349,11 @@
static inline u32 nfsd_suppattrs2(u32 minorversion)
{
- return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD2
- : NFSD4_SUPPORTED_ATTRS_WORD2;
+ switch (minorversion) {
+ default: return NFSD4_2_SUPPORTED_ATTRS_WORD2;
+ case 1: return NFSD4_1_SUPPORTED_ATTRS_WORD2;
+ case 0: return NFSD4_SUPPORTED_ATTRS_WORD2;
+ }
}
/* These will return ERR_INVAL if specified in GETATTR or READDIR. */
@@ -356,7 +366,11 @@
#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 84ce601..1e757fa 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 @@
return 0;
return 1;
}
+#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
+__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ struct xdr_netobj *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->data, 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 xdr_netobj *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 8d2b40d..a4be2e3 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -55,6 +55,8 @@
__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 xdr_netobj *);
#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 3b271d2..b3ed644 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -40,6 +40,7 @@
#include "state.h"
#include "nfsd.h"
+#define NFSD4_MAX_SEC_LABEL_LEN 2048
#define NFSD4_MAX_TAGLEN 128
#define XDR_LEN(n) (((n) + 3) & ~3)
@@ -118,6 +119,7 @@
struct iattr cr_iattr; /* request */
struct nfsd4_change_info cr_cinfo; /* response */
struct nfs4_acl *cr_acl;
+ struct xdr_netobj cr_label;
};
#define cr_linklen u.link.namelen
#define cr_linkname u.link.name
@@ -246,6 +248,7 @@
struct nfs4_file *op_file; /* used during processing */
struct nfs4_ol_stateid *op_stp; /* used during processing */
struct nfs4_acl *op_acl;
+ struct xdr_netobj op_label;
};
#define op_iattr iattr
@@ -330,6 +333,7 @@
u32 sa_bmval[3]; /* request */
struct iattr sa_iattr; /* request */
struct nfs4_acl *sa_acl;
+ struct xdr_netobj sa_label;
};
struct nfsd4_setclientid {