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Commit fe542cf5 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by James Morris
Browse files

LSM: Move security_path_chmod()/security_path_chown() to after mutex_lock(). 



We should call security_path_chmod()/security_path_chown() after mutex_lock()
in order to avoid races.

Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: default avatarJohn Johansen <john.johansen@canonical.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 85c3b529

fs/open.c

+15 −21
Original line number Diff line number Diff line
@@ -619,17 +619,17 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode) 
	err = mnt_want_write_file(file);

	if (err)

		goto out_putf;

	mutex_lock(&inode->i_mutex);

	err = security_path_chmod(dentry, file->f_vfsmnt, mode);

	if (err)

		goto out_drop_write;

	mutex_lock(&inode->i_mutex);

		goto out_unlock;

	if (mode == (mode_t) -1)

		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);

out_unlock:

	mutex_unlock(&inode->i_mutex);

out_drop_write:

	mnt_drop_write(file->f_path.mnt);

out_putf:

	fput(file);
@@ -652,17 +652,17 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode) 
	error = mnt_want_write(path.mnt);

	if (error)

		goto dput_and_out;

	mutex_lock(&inode->i_mutex);

	error = security_path_chmod(path.dentry, path.mnt, mode);

	if (error)

		goto out_drop_write;

	mutex_lock(&inode->i_mutex);

		goto out_unlock;

	if (mode == (mode_t) -1)

		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(path.dentry, &newattrs);

out_unlock:

	mutex_unlock(&inode->i_mutex);

out_drop_write:

	mnt_drop_write(path.mnt);

dput_and_out:

	path_put(&path);
@@ -675,9 +675,9 @@ SYSCALL_DEFINE2(chmod, const char __user *, filename, mode_t, mode) 
	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 path *path, uid_t user, gid_t group)

{

	struct inode *inode = dentry->d_inode;

	struct inode *inode = path->dentry->d_inode;

	int error;

	struct iattr newattrs;
@@ -694,7 +694,9 @@ static int chown_common(struct dentry * dentry, uid_t user, gid_t group) 
		newattrs.ia_valid |=

			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;

	mutex_lock(&inode->i_mutex);

	error = notify_change(dentry, &newattrs);

	error = security_path_chown(path, user, group);

	if (!error)

		error = notify_change(path->dentry, &newattrs);

	mutex_unlock(&inode->i_mutex);



	return error;
@@ -711,9 +713,7 @@ 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);

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

	mnt_drop_write(path.mnt);

out_release:

	path_put(&path);
@@ -738,9 +738,7 @@ 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);

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

	mnt_drop_write(path.mnt);

out_release:

	path_put(&path);
@@ -759,9 +757,7 @@ 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);

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

	mnt_drop_write(path.mnt);

out_release:

	path_put(&path);
@@ -784,9 +780,7 @@ 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);

	error = chown_common(&file->f_path, user, group);

	mnt_drop_write(file->f_path.mnt);

out_fput:

	fput(file);