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: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/open.c b/fs/open.c
index 201041d..b4b31d2 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -619,17 +619,17 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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);