X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=fs%2Fnfsd%2Fnfsfh.c;h=78d8ebf162caeb1cbf3b85f028b0375f4ee2c626;hp=1eb771d79cca09a51326541dc76f3db3405f9245;hb=8e498751f2f36074ffa6fc7f0a9ec6e055b350e6;hpb=5216a8e70e25b01cbd2915cd0442fb96deb2c262

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 1eb771d..78d8ebf 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -27,9 +27,6 @@
 #define NFSDDBG_FACILITY		NFSDDBG_FH
 
 
-static int nfsd_nr_verified;
-static int nfsd_nr_put;
-
 /*
  * our acceptability function.
  * if NOSUBTREECHECK, accept anything
@@ -51,7 +48,7 @@ static int nfsd_acceptable(void *expv, struct dentry *dentry)
 		/* make sure parents give x permission to user */
 		int err;
 		parent = dget_parent(tdentry);
-		err = permission(parent->d_inode, MAY_EXEC, NULL);
+		err = inode_permission(parent->d_inode, MAY_EXEC);
 		if (err < 0) {
 			dput(parent);
 			break;
@@ -113,125 +110,192 @@ static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 }
 
 /*
- * Perform sanity checks on the dentry in a client's file handle.
- *
- * Note that the file handle dentry may need to be freed even after
- * an error return.
- *
- * This is only called at the start of an nfsproc call, so fhp points to
- * a svc_fh which is all 0 except for the over-the-wire file handle.
+ * Use the given filehandle to look up the corresponding export and
+ * dentry.  On success, the results are used to set fh_export and
+ * fh_dentry.
  */
-__be32
-fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
+static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 {
 	struct knfsd_fh	*fh = &fhp->fh_handle;
-	struct svc_export *exp = NULL;
-	struct dentry	*dentry;
-	__be32		error = 0;
-
-	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
+	struct fid *fid = NULL, sfid;
+	struct svc_export *exp;
+	struct dentry *dentry;
+	int fileid_type;
+	int data_left = fh->fh_size/4;
+	__be32 error;
 
-	if (!fhp->fh_dentry) {
-		struct fid *fid = NULL, sfid;
-		int fileid_type;
-		int data_left = fh->fh_size/4;
-
-		error = nfserr_stale;
-		if (rqstp->rq_vers > 2)
-			error = nfserr_badhandle;
-		if (rqstp->rq_vers == 4 && fh->fh_size == 0)
-			return nfserr_nofilehandle;
-
-		if (fh->fh_version == 1) {
-			int len;
-			if (--data_left<0) goto out;
-			switch (fh->fh_auth_type) {
-			case 0: break;
-			default: goto out;
-			}
-			len = key_len(fh->fh_fsid_type) / 4;
-			if (len == 0) goto out;
-			if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
-				/* deprecated, convert to type 3 */
-				len = key_len(FSID_ENCODE_DEV)/4;
-				fh->fh_fsid_type = FSID_ENCODE_DEV;
-				fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
-				fh->fh_fsid[1] = fh->fh_fsid[2];
-			}
-			if ((data_left -= len)<0) goto out;
-			exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
-					    fh->fh_auth);
-			fid = (struct fid *)(fh->fh_auth + len);
-		} else {
-			__u32 tfh[2];
-			dev_t xdev;
-			ino_t xino;
-			if (fh->fh_size != NFS_FHSIZE)
-				goto out;
-			/* assume old filehandle format */
-			xdev = old_decode_dev(fh->ofh_xdev);
-			xino = u32_to_ino_t(fh->ofh_xino);
-			mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
-			exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
-		}
+	error = nfserr_stale;
+	if (rqstp->rq_vers > 2)
+		error = nfserr_badhandle;
+	if (rqstp->rq_vers == 4 && fh->fh_size == 0)
+		return nfserr_nofilehandle;
 
-		error = nfserr_stale;
-		if (PTR_ERR(exp) == -ENOENT)
-			goto out;
+	if (fh->fh_version == 1) {
+		int len;
 
-		if (IS_ERR(exp)) {
-			error = nfserrno(PTR_ERR(exp));
-			goto out;
+		if (--data_left < 0)
+			return error;
+		if (fh->fh_auth_type != 0)
+			return error;
+		len = key_len(fh->fh_fsid_type) / 4;
+		if (len == 0)
+			return error;
+		if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
+			/* deprecated, convert to type 3 */
+			len = key_len(FSID_ENCODE_DEV)/4;
+			fh->fh_fsid_type = FSID_ENCODE_DEV;
+			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
+			fh->fh_fsid[1] = fh->fh_fsid[2];
 		}
+		data_left -= len;
+		if (data_left < 0)
+			return error;
+		exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
+		fid = (struct fid *)(fh->fh_auth + len);
+	} else {
+		__u32 tfh[2];
+		dev_t xdev;
+		ino_t xino;
+
+		if (fh->fh_size != NFS_FHSIZE)
+			return error;
+		/* assume old filehandle format */
+		xdev = old_decode_dev(fh->ofh_xdev);
+		xino = u32_to_ino_t(fh->ofh_xino);
+		mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
+		exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
+	}
 
+	error = nfserr_stale;
+	if (PTR_ERR(exp) == -ENOENT)
+		return error;
+
+	if (IS_ERR(exp))
+		return nfserrno(PTR_ERR(exp));
+
+	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
+		/* Elevate privileges so that the lack of 'r' or 'x'
+		 * permission on some parent directory will
+		 * not stop exportfs_decode_fh from being able
+		 * to reconnect a directory into the dentry cache.
+		 * The same problem can affect "SUBTREECHECK" exports,
+		 * but as nfsd_acceptable depends on correct
+		 * access control settings being in effect, we cannot
+		 * fix that case easily.
+		 */
+		struct cred *new = prepare_creds();
+		if (!new)
+			return nfserrno(-ENOMEM);
+		new->cap_effective =
+			cap_raise_nfsd_set(new->cap_effective,
+					   new->cap_permitted);
+		put_cred(override_creds(new));
+		put_cred(new);
+	} else {
 		error = nfsd_setuser_and_check_port(rqstp, exp);
 		if (error)
 			goto out;
+	}
 
-		/*
-		 * Look up the dentry using the NFS file handle.
-		 */
-		error = nfserr_stale;
-		if (rqstp->rq_vers > 2)
-			error = nfserr_badhandle;
-
-		if (fh->fh_version != 1) {
-			sfid.i32.ino = fh->ofh_ino;
-			sfid.i32.gen = fh->ofh_generation;
-			sfid.i32.parent_ino = fh->ofh_dirino;
-			fid = &sfid;
-			data_left = 3;
-			if (fh->ofh_dirino == 0)
-				fileid_type = FILEID_INO32_GEN;
-			else
-				fileid_type = FILEID_INO32_GEN_PARENT;
-		} else
-			fileid_type = fh->fh_fileid_type;
-
-		if (fileid_type == FILEID_ROOT)
-			dentry = dget(exp->ex_path.dentry);
-		else {
-			dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
-					data_left, fileid_type,
-					nfsd_acceptable, exp);
-		}
-		if (dentry == NULL)
-			goto out;
-		if (IS_ERR(dentry)) {
-			if (PTR_ERR(dentry) != -EINVAL)
-				error = nfserrno(PTR_ERR(dentry));
+	/*
+	 * Look up the dentry using the NFS file handle.
+	 */
+	error = nfserr_stale;
+	if (rqstp->rq_vers > 2)
+		error = nfserr_badhandle;
+
+	if (fh->fh_version != 1) {
+		sfid.i32.ino = fh->ofh_ino;
+		sfid.i32.gen = fh->ofh_generation;
+		sfid.i32.parent_ino = fh->ofh_dirino;
+		fid = &sfid;
+		data_left = 3;
+		if (fh->ofh_dirino == 0)
+			fileid_type = FILEID_INO32_GEN;
+		else
+			fileid_type = FILEID_INO32_GEN_PARENT;
+	} else
+		fileid_type = fh->fh_fileid_type;
+
+	if (fileid_type == FILEID_ROOT)
+		dentry = dget(exp->ex_path.dentry);
+	else {
+		dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
+				data_left, fileid_type,
+				nfsd_acceptable, exp);
+	}
+	if (dentry == NULL)
+		goto out;
+	if (IS_ERR(dentry)) {
+		if (PTR_ERR(dentry) != -EINVAL)
+			error = nfserrno(PTR_ERR(dentry));
+		goto out;
+	}
+
+	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
+		error = nfsd_setuser_and_check_port(rqstp, exp);
+		if (error) {
+			dput(dentry);
 			goto out;
 		}
+	}
 
-		if (S_ISDIR(dentry->d_inode->i_mode) &&
-		    (dentry->d_flags & DCACHE_DISCONNECTED)) {
-			printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
-			       dentry->d_parent->d_name.name, dentry->d_name.name);
-		}
+	if (S_ISDIR(dentry->d_inode->i_mode) &&
+			(dentry->d_flags & DCACHE_DISCONNECTED)) {
+		printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
+				dentry->d_parent->d_name.name, dentry->d_name.name);
+	}
+
+	fhp->fh_dentry = dentry;
+	fhp->fh_export = exp;
+	return 0;
+out:
+	exp_put(exp);
+	return error;
+}
+
+/**
+ * fh_verify - filehandle lookup and access checking
+ * @rqstp: pointer to current rpc request
+ * @fhp: filehandle to be verified
+ * @type: expected type of object pointed to by filehandle
+ * @access: type of access needed to object
+ *
+ * Look up a dentry from the on-the-wire filehandle, check the client's
+ * access to the export, and set the current task's credentials.
+ *
+ * Regardless of success or failure of fh_verify(), fh_put() should be
+ * called on @fhp when the caller is finished with the filehandle.
+ *
+ * fh_verify() may be called multiple times on a given filehandle, for
+ * example, when processing an NFSv4 compound.  The first call will look
+ * up a dentry using the on-the-wire filehandle.  Subsequent calls will
+ * skip the lookup and just perform the other checks and possibly change
+ * the current task's credentials.
+ *
+ * @type specifies the type of object expected using one of the S_IF*
+ * constants defined in include/linux/stat.h.  The caller may use zero
+ * to indicate that it doesn't care, or a negative integer to indicate
+ * that it expects something not of the given type.
+ *
+ * @access is formed from the NFSD_MAY_* constants defined in
+ * include/linux/nfsd/nfsd.h.
+ */
+__be32
+fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
+{
+	struct svc_export *exp;
+	struct dentry	*dentry;
+	__be32		error;
 
-		fhp->fh_dentry = dentry;
-		fhp->fh_export = exp;
-		nfsd_nr_verified++;
+	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
+
+	if (!fhp->fh_dentry) {
+		error = nfsd_set_fh_dentry(rqstp, fhp);
+		if (error)
+			goto out;
+		dentry = fhp->fh_dentry;
+		exp = fhp->fh_export;
 	} else {
 		/*
 		 * just rechecking permissions
@@ -252,24 +316,32 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 		if (error)
 			goto out;
 	}
-	cache_get(&exp->h);
-
 
 	error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 	if (error)
 		goto out;
 
-	if (!(access & MAY_LOCK)) {
-		/*
-		 * pseudoflavor restrictions are not enforced on NLM,
-		 * which clients virtually always use auth_sys for,
-		 * even while using RPCSEC_GSS for NFS.
-		 */
-		error = check_nfsd_access(exp, rqstp);
-		if (error)
-			goto out;
-	}
+	/*
+	 * pseudoflavor restrictions are not enforced on NLM,
+	 * which clients virtually always use auth_sys for,
+	 * even while using RPCSEC_GSS for NFS.
+	 */
+	if (access & NFSD_MAY_LOCK)
+		goto skip_pseudoflavor_check;
+	/*
+	 * Clients may expect to be able to use auth_sys during mount,
+	 * even if they use gss for everything else; see section 2.3.2
+	 * of rfc 2623.
+	 */
+	if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
+			&& exp->ex_path.dentry == dentry)
+		goto skip_pseudoflavor_check;
 
+	error = check_nfsd_access(exp, rqstp);
+	if (error)
+		goto out;
+
+skip_pseudoflavor_check:
 	/* Finally, check access permissions. */
 	error = nfsd_permission(rqstp, exp, dentry, access);
 
@@ -281,8 +353,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 			access, ntohl(error));
 	}
 out:
-	if (exp && !IS_ERR(exp))
-		exp_put(exp);
 	if (error == nfserr_stale)
 		nfsdstats.fh_stale++;
 	return error;
@@ -327,6 +397,40 @@ static inline void _fh_update_old(struct dentry *dentry,
 		fh->ofh_dirino = 0;
 }
 
+static bool is_root_export(struct svc_export *exp)
+{
+	return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
+}
+
+static struct super_block *exp_sb(struct svc_export *exp)
+{
+	return exp->ex_path.dentry->d_inode->i_sb;
+}
+
+static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
+{
+	switch (fsid_type) {
+	case FSID_DEV:
+		if (!old_valid_dev(exp_sb(exp)->s_dev))
+			return 0;
+		/* FALL THROUGH */
+	case FSID_MAJOR_MINOR:
+	case FSID_ENCODE_DEV:
+		return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
+	case FSID_NUM:
+		return exp->ex_flags & NFSEXP_FSID;
+	case FSID_UUID8:
+	case FSID_UUID16:
+		if (!is_root_export(exp))
+			return 0;
+		/* fall through */
+	case FSID_UUID4_INUM:
+	case FSID_UUID16_INUM:
+		return exp->ex_uuid != NULL;
+	}
+	return 1;
+}
+
 __be32
 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 	   struct svc_fh *ref_fh)
@@ -344,8 +448,7 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 	struct inode * inode = dentry->d_inode;
 	struct dentry *parent = dentry->d_parent;
 	__u32 *datap;
-	dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev;
-	int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root);
+	dev_t ex_dev = exp_sb(exp)->s_dev;
 
 	dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 		MAJOR(ex_dev), MINOR(ex_dev),
@@ -377,54 +480,29 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 			goto retry;
 		}
 
-		/* Need to check that this type works for this
-		 * export point.  As the fsid -> filesystem mapping
-		 * was guided by user-space, there is no guarantee
-		 * that the filesystem actually supports that fsid
-		 * type. If it doesn't we loop around again without
-		 * ref_fh set.
+		/*
+		 * As the fsid -> filesystem mapping was guided by
+		 * user-space, there is no guarantee that the filesystem
+		 * actually supports that fsid type. If it doesn't we
+		 * loop around again without ref_fh set.
 		 */
-		switch(fsid_type) {
-		case FSID_DEV:
-			if (!old_valid_dev(ex_dev))
-				goto retry;
-			/* FALL THROUGH */
-		case FSID_MAJOR_MINOR:
-		case FSID_ENCODE_DEV:
-			if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
-			      & FS_REQUIRES_DEV))
-				goto retry;
-			break;
-		case FSID_NUM:
-			if (! (exp->ex_flags & NFSEXP_FSID))
-				goto retry;
-			break;
-		case FSID_UUID8:
-		case FSID_UUID16:
-			if (!root_export)
-				goto retry;
-			/* fall through */
-		case FSID_UUID4_INUM:
-		case FSID_UUID16_INUM:
-			if (exp->ex_uuid == NULL)
-				goto retry;
-			break;
-		}
+		if (!fsid_type_ok_for_exp(fsid_type, exp))
+			goto retry;
+	} else if (exp->ex_flags & NFSEXP_FSID) {
+		fsid_type = FSID_NUM;
 	} else if (exp->ex_uuid) {
 		if (fhp->fh_maxsize >= 64) {
-			if (root_export)
+			if (is_root_export(exp))
 				fsid_type = FSID_UUID16;
 			else
 				fsid_type = FSID_UUID16_INUM;
 		} else {
-			if (root_export)
+			if (is_root_export(exp))
 				fsid_type = FSID_UUID8;
 			else
 				fsid_type = FSID_UUID4_INUM;
 		}
-	} else if (exp->ex_flags & NFSEXP_FSID)
-		fsid_type = FSID_NUM;
-	else if (!old_valid_dev(ex_dev))
+	} else if (!old_valid_dev(ex_dev))
 		/* for newer device numbers, we must use a newer fsid format */
 		fsid_type = FSID_ENCODE_DEV;
 	else
@@ -478,7 +556,6 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 			return nfserr_opnotsupp;
 	}
 
-	nfsd_nr_verified++;
 	return 0;
 }
 
@@ -535,7 +612,6 @@ fh_put(struct svc_fh *fhp)
 		fhp->fh_pre_saved = 0;
 		fhp->fh_post_saved = 0;
 #endif
-		nfsd_nr_put++;
 	}
 	if (exp) {
 		cache_put(&exp->h, &svc_export_cache);
@@ -571,8 +647,7 @@ enum fsid_source fsid_source(struct svc_fh *fhp)
 	case FSID_DEV:
 	case FSID_ENCODE_DEV:
 	case FSID_MAJOR_MINOR:
-		if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
-		    & FS_REQUIRES_DEV)
+		if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 			return FSIDSOURCE_DEV;
 		break;
 	case FSID_NUM: