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

fs/open.c

+20 −4
Original line number Diff line number Diff line
@@ -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);
@@ -700,6 +708,8 @@ 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 = security_path_chown(&path, user, group);

	if (!error)

		error = chown_common(path.dentry, user, group);

	mnt_drop_write(path.mnt);

out_release:
@@ -725,6 +735,8 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, 
	error = mnt_want_write(path.mnt);

	if (error)

		goto out_release;

	error = security_path_chown(&path, user, group);

	if (!error)

		error = chown_common(path.dentry, user, group);

	mnt_drop_write(path.mnt);

out_release:
@@ -744,6 +756,8 @@ 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 = security_path_chown(&path, user, group);

	if (!error)

		error = chown_common(path.dentry, user, group);

	mnt_drop_write(path.mnt);

out_release:
@@ -767,6 +781,8 @@ 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 = 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:

include/linux/security.h

+30 −0
Original line number Diff line number Diff line
@@ -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

security/capability.c

+13 −0
Original line number Diff line number Diff line
@@ -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);

security/security.c

+15 −0
Original line number Diff line number Diff line
@@ -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)