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

Kentaro Takeda
2008-01-09T00:56:37Z

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@I-love.SAKURA.ne.jp>
---
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;

--