[TOMOYO #6 retry 04/21] Replace VFS with wrapper functions.

[Kentaro Takeda]

This patch replaces VFS helper function calls caused by
userland process's request with VFS wrapper functions call.
I don't have a plan to control VFS helper function calls
caused by the kernel. Therefore, this patch doesn't modify
individual filesystems in fs/*/ directory.

I need to know the vfsmount parameter from LSM hooks so that
I can calculate the pathname of a given dentry.

Scanning the caller process's namespace list cannot reliably
determine which vfsmount the given dentry belongs to
because the corresponding vfsmount parameter appears for
multiple times when bind mounts are used.

What is worse, accessing namespace_sem from LSM hooks triggers
AB-BA deadlock. Therefore, I definitely need either AppArmor's
"Add struct vfsmount parameter to ..." patches or this patch.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
 fs/namei.c         |   34 +++++++++++++++++++---------------
 fs/open.c          |   23 +++++++++++++----------
 net/unix/af_unix.c |    3 ++-
 3 files changed, 34 insertions(+), 26 deletions(-)

--- linux-2.6-mm.orig/fs/open.c
+++ linux-2.6-mm/fs/open.c
@@ -271,7 +271,8 @@ static long do_sys_truncate(const char _
 	error = locks_verify_truncate(inode, NULL, length);
 	if (!error) {
 		DQUOT_INIT(inode);
-		error = do_truncate(nd.path.dentry, length, 0, NULL);
+		error = do_truncate2(nd.path.dentry, nd.path.mnt, length, 0,
+				     NULL);
 	}
 
 put_write_and_out:
@@ -326,7 +327,8 @@ static long do_sys_ftruncate(unsigned in
 
 	error = locks_verify_truncate(inode, file, length);
 	if (!error)
-		error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
+		error = do_truncate2(dentry, file->f_path.mnt, length,
+				     ATTR_MTIME|ATTR_CTIME, file);
 out_putf:
 	fput(file);
 out:
@@ -589,7 +591,7 @@ asmlinkage long sys_fchmod(unsigned int 
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	err = notify_change(dentry, &newattrs);
+	err = notify_change2(dentry, file->f_path.mnt, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 
 out_drop_write:
@@ -626,7 +628,7 @@ asmlinkage long sys_fchmodat(int dfd, co
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	error = notify_change(nd.path.dentry, &newattrs);
+	error = notify_change2(nd.path.dentry, nd.path.mnt, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 
 out_drop_write:
@@ -642,7 +644,8 @@ asmlinkage long sys_chmod(const char __u
 	return sys_fchmodat(AT_FDCWD, filename, mode);
 }
 
-static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
+static int chown_common(struct dentry *dentry, struct vfsmount *mnt,
+			uid_t user, gid_t group)
 {
 	struct inode * inode;
 	int error;
@@ -669,7 +672,7 @@ static int chown_common(struct dentry * 
 		newattrs.ia_valid |=
 			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 	mutex_lock(&inode->i_mutex);
-	error = notify_change(dentry, &newattrs);
+	error = notify_change2(dentry, mnt, &newattrs);
 	mutex_unlock(&inode->i_mutex);
 out:
 	return error;
@@ -686,7 +689,7 @@ asmlinkage long sys_chown(const char __u
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
+	error = chown_common(nd.path.dentry, nd.path.mnt, user, group);
 	mnt_drop_write(nd.path.mnt);
 out_release:
 	path_put(&nd.path);
@@ -711,7 +714,7 @@ asmlinkage long sys_fchownat(int dfd, co
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
+	error = chown_common(nd.path.dentry, nd.path.mnt, user, group);
 	mnt_drop_write(nd.path.mnt);
 out_release:
 	path_put(&nd.path);
@@ -730,7 +733,7 @@ asmlinkage long sys_lchown(const char __
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
+	error = chown_common(nd.path.dentry, nd.path.mnt, user, group);
 	mnt_drop_write(nd.path.mnt);
 out_release:
 	path_put(&nd.path);
@@ -754,7 +757,7 @@ asmlinkage long sys_fchown(unsigned int 
 		goto out_fput;
 	dentry = file->f_path.dentry;
 	audit_inode(NULL, dentry);
-	error = chown_common(dentry, user, group);
+	error = chown_common(dentry, file->f_vfsmnt, user, group);
 	mnt_drop_write(file->f_vfsmnt);
 out_fput:
 	fput(file);
--- linux-2.6-mm.orig/fs/namei.c
+++ linux-2.6-mm/fs/namei.c
@@ -1663,7 +1663,7 @@ int may_open(struct nameidata *nd, int a
 		if (!error) {
 			DQUOT_INIT(inode);
 
-			error = do_truncate(dentry, 0,
+			error = do_truncate2(dentry, nd->path.mnt, 0,
 					    ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
 					    NULL);
 		}
@@ -1690,7 +1690,7 @@ static int __open_namei_create(struct na
 
 	if (!IS_POSIXACL(dir->d_inode))
 		mode &= ~current->fs->umask;
-	error = vfs_create(dir->d_inode, path->dentry, mode, nd);
+	error = vfs_create2(dir->d_inode, path->dentry, mode, nd);
 	mutex_unlock(&dir->d_inode->i_mutex);
 	dput(nd->path.dentry);
 	nd->path.dentry = path->dentry;
@@ -2078,16 +2078,17 @@ asmlinkage long sys_mknodat(int dfd, con
 		goto out_dput;
 	switch (mode & S_IFMT) {
 		case 0: case S_IFREG:
-			error = vfs_create(nd.path.dentry->d_inode, dentry,
-						mode, &nd);
+			error = vfs_create2(nd.path.dentry->d_inode, dentry,
+					    mode, &nd);
 			break;
 		case S_IFCHR: case S_IFBLK:
-			error = vfs_mknod(nd.path.dentry->d_inode, dentry, mode,
-					new_decode_dev(dev));
+			error = vfs_mknod2(nd.path.dentry->d_inode, dentry,
+					   nd.path.mnt, mode,
+					   new_decode_dev(dev));
 			break;
 		case S_IFIFO: case S_IFSOCK:
-			error = vfs_mknod(nd.path.dentry->d_inode, dentry,
-						mode, 0);
+			error = vfs_mknod2(nd.path.dentry->d_inode, dentry,
+					   nd.path.mnt, mode, 0);
 			break;
 	}
 	mnt_drop_write(nd.path.mnt);
@@ -2154,7 +2155,7 @@ asmlinkage long sys_mkdirat(int dfd, con
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_dput;
-	error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
+	error = vfs_mkdir2(nd.path.dentry->d_inode, dentry, nd.path.mnt, mode);
 	mnt_drop_write(nd.path.mnt);
 out_dput:
 	dput(dentry);
@@ -2266,7 +2267,7 @@ static long do_rmdir(int dfd, const char
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto exit3;
-	error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
+	error = vfs_rmdir2(nd.path.dentry->d_inode, dentry, nd.path.mnt);
 	mnt_drop_write(nd.path.mnt);
 exit3:
 	dput(dentry);
@@ -2352,7 +2353,8 @@ static long do_unlinkat(int dfd, const c
 		error = mnt_want_write(nd.path.mnt);
 		if (error)
 			goto exit2;
-		error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+		error = vfs_unlink2(nd.path.dentry->d_inode, dentry,
+				    nd.path.mnt);
 		mnt_drop_write(nd.path.mnt);
 	exit2:
 		dput(dentry);
@@ -2437,7 +2439,8 @@ asmlinkage long sys_symlinkat(const char
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_dput;
-	error = vfs_symlink(nd.path.dentry->d_inode, dentry, from, S_IALLUGO);
+	error = vfs_symlink2(nd.path.dentry->d_inode, dentry, nd.path.mnt, from,
+			     S_IALLUGO);
 	mnt_drop_write(nd.path.mnt);
 out_dput:
 	dput(dentry);
@@ -2537,7 +2540,8 @@ asmlinkage long sys_linkat(int olddfd, c
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_dput;
-	error = vfs_link(old_nd.path.dentry, nd.path.dentry->d_inode, new_dentry);
+	error = vfs_link2(old_nd.path.dentry, nd.path.dentry->d_inode,
+			  new_dentry, nd.path.mnt);
 	mnt_drop_write(nd.path.mnt);
 out_dput:
 	dput(new_dentry);
@@ -2768,8 +2772,8 @@ static int do_rename(int olddfd, const c
 	error = mnt_want_write(oldnd.path.mnt);
 	if (error)
 		goto exit5;
-	error = vfs_rename(old_dir->d_inode, old_dentry,
-				   new_dir->d_inode, new_dentry);
+	error = vfs_rename2(old_dir->d_inode, old_dentry,
+			    new_dir->d_inode, new_dentry, newnd.path.mnt);
 	mnt_drop_write(oldnd.path.mnt);
 exit5:
 	dput(new_dentry);
--- linux-2.6-mm.orig/net/unix/af_unix.c
+++ linux-2.6-mm/net/unix/af_unix.c
@@ -822,7 +822,8 @@ static int unix_bind(struct socket *sock
 		err = mnt_want_write(nd.path.mnt);
 		if (err)
 			goto out_mknod_dput;
-		err = vfs_mknod(nd.path.dentry->d_inode, dentry, mode, 0);
+		err = vfs_mknod2(nd.path.dentry->d_inode, dentry, nd.path.mnt,
+				 mode, 0);
 		mnt_drop_write(nd.path.mnt);
 		if (err)
 			goto out_mknod_dput;

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/