4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Seth Forshee <[email protected]> [ Upstream commit 1328c727004d432bbdfba0ffa02a166df04c7305 ] may_create() rejects creation of inodes with ids which lack a mapping into s_user_ns. However for O_CREAT may_o_create() is is used instead. Add a similar check there. Fixes: 036d523641c6 ("vfs: Don't create inodes with a uid or gid unknown to the vfs") Signed-off-by: Seth Forshee <[email protected]> Signed-off-by: "Eric W. Biederman" <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/namei.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/namei.c +++ b/fs/namei.c @@ -2971,10 +2971,16 @@ static inline int open_to_namei_flags(in static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t mode) { + struct user_namespace *s_user_ns; int error = security_path_mknod(dir, dentry, mode, 0); if (error) return error; + s_user_ns = dir->dentry->d_sb->s_user_ns; + if (!kuid_has_mapping(s_user_ns, current_fsuid()) || + !kgid_has_mapping(s_user_ns, current_fsgid())) + return -EOVERFLOW; + error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC); if (error) return error;
