4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
[ 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 <seth.forshee@xxxxxxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;