Commit 89eda068 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by James Morris

LSM: Add security_path_chmod() and security_path_chown().

This patch allows pathname based LSM modules to check chmod()/chown()
operations. Since notify_change() does not receive "struct vfsmount *",
we add security_path_chmod() and security_path_chown() to the caller of
notify_change().

These hooks are used by TOMOYO.
Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 941fc5b2
......@@ -616,6 +616,9 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
err = mnt_want_write_file(file);
if (err)
goto out_putf;
err = security_path_chmod(dentry, file->f_vfsmnt, mode);
if (err)
goto out_drop_write;
mutex_lock(&inode->i_mutex);
if (mode == (mode_t) -1)
mode = inode->i_mode;
......@@ -623,6 +626,7 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode)
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
err = notify_change(dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
out_drop_write:
mnt_drop_write(file->f_path.mnt);
out_putf:
fput(file);
......@@ -645,6 +649,9 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode)
error = mnt_want_write(path.mnt);
if (error)
goto dput_and_out;
error = security_path_chmod(path.dentry, path.mnt, mode);
if (error)
goto out_drop_write;
mutex_lock(&inode->i_mutex);
if (mode == (mode_t) -1)
mode = inode->i_mode;
......@@ -652,6 +659,7 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode)
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
error = notify_change(path.dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
out_drop_write:
mnt_drop_write(path.mnt);
dput_and_out:
path_put(&path);
......@@ -700,7 +708,9 @@ SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
error = mnt_want_write(path.mnt);
if (error)
goto out_release;
error = chown_common(path.dentry, user, group);
error = security_path_chown(&path, user, group);
if (!error)
error = chown_common(path.dentry, user, group);
mnt_drop_write(path.mnt);
out_release:
path_put(&path);
......@@ -725,7 +735,9 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
error = mnt_want_write(path.mnt);
if (error)
goto out_release;
error = chown_common(path.dentry, user, group);
error = security_path_chown(&path, user, group);
if (!error)
error = chown_common(path.dentry, user, group);
mnt_drop_write(path.mnt);
out_release:
path_put(&path);
......@@ -744,7 +756,9 @@ SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group
error = mnt_want_write(path.mnt);
if (error)
goto out_release;
error = chown_common(path.dentry, user, group);
error = security_path_chown(&path, user, group);
if (!error)
error = chown_common(path.dentry, user, group);
mnt_drop_write(path.mnt);
out_release:
path_put(&path);
......@@ -767,7 +781,9 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
goto out_fput;
dentry = file->f_path.dentry;
audit_inode(NULL, dentry);
error = chown_common(dentry, user, group);
error = security_path_chown(&file->f_path, user, group);
if (!error)
error = chown_common(dentry, user, group);
mnt_drop_write(file->f_path.mnt);
out_fput:
fput(file);
......
......@@ -447,6 +447,18 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* @new_dir contains the path structure for parent of the new link.
* @new_dentry contains the dentry structure of the new link.
* Return 0 if permission is granted.
* @path_chmod:
* Check for permission to change DAC's permission of a file or directory.
* @dentry contains the dentry structure.
* @mnt contains the vfsmnt structure.
* @mode contains DAC's mode.
* Return 0 if permission is granted.
* @path_chown:
* Check for permission to change owner/group of a file or directory.
* @path contains the path structure.
* @uid contains new owner's ID.
* @gid contains new group's ID.
* Return 0 if permission is granted.
* @inode_readlink:
* Check the permission to read the symbolic link.
* @dentry contains the dentry structure for the file link.
......@@ -1488,6 +1500,9 @@ struct security_operations {
struct dentry *new_dentry);
int (*path_rename) (struct path *old_dir, struct dentry *old_dentry,
struct path *new_dir, struct dentry *new_dentry);
int (*path_chmod) (struct dentry *dentry, struct vfsmount *mnt,
mode_t mode);
int (*path_chown) (struct path *path, uid_t uid, gid_t gid);
#endif
int (*inode_alloc_security) (struct inode *inode);
......@@ -2952,6 +2967,9 @@ int security_path_link(struct dentry *old_dentry, struct path *new_dir,
struct dentry *new_dentry);
int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
struct path *new_dir, struct dentry *new_dentry);
int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
mode_t mode);
int security_path_chown(struct path *path, uid_t uid, gid_t gid);
#else /* CONFIG_SECURITY_PATH */
static inline int security_path_unlink(struct path *dir, struct dentry *dentry)
{
......@@ -3001,6 +3019,18 @@ static inline int security_path_rename(struct path *old_dir,
{
return 0;
}
static inline int security_path_chmod(struct dentry *dentry,
struct vfsmount *mnt,
mode_t mode)
{
return 0;
}
static inline int security_path_chown(struct path *path, uid_t uid, gid_t gid)
{
return 0;
}
#endif /* CONFIG_SECURITY_PATH */
#ifdef CONFIG_KEYS
......
......@@ -308,6 +308,17 @@ static int cap_path_truncate(struct path *path, loff_t length,
{
return 0;
}
static int cap_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
mode_t mode)
{
return 0;
}
static int cap_path_chown(struct path *path, uid_t uid, gid_t gid)
{
return 0;
}
#endif
static int cap_file_permission(struct file *file, int mask)
......@@ -977,6 +988,8 @@ void security_fixup_ops(struct security_operations *ops)
set_to_cap_if_null(ops, path_link);
set_to_cap_if_null(ops, path_rename);
set_to_cap_if_null(ops, path_truncate);
set_to_cap_if_null(ops, path_chmod);
set_to_cap_if_null(ops, path_chown);
#endif
set_to_cap_if_null(ops, file_permission);
set_to_cap_if_null(ops, file_alloc_security);
......
......@@ -434,6 +434,21 @@ int security_path_truncate(struct path *path, loff_t length,
return 0;
return security_ops->path_truncate(path, length, time_attrs);
}
int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
mode_t mode)
{
if (unlikely(IS_PRIVATE(dentry->d_inode)))
return 0;
return security_ops->path_chmod(dentry, mnt, mode);
}
int security_path_chown(struct path *path, uid_t uid, gid_t gid)
{
if (unlikely(IS_PRIVATE(path->dentry->d_inode)))
return 0;
return security_ops->path_chown(path, uid, gid);
}
#endif
int security_inode_create(struct inode *dir, struct dentry *dentry, int mode)
......
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