[PATCH review 01/11] fs: Refuse uid/gid changes which don't map into s_user_ns
From: Eric W. Biederman <hidden>
Date: 2016-07-02 17:33:39
Also in:
linux-fsdevel
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Seth Forshee <redacted> Add checks to notify_change to verify that uid and gid changes will map into the superblock's user namespace. If they do not fail with -EOVERFLOW. This is mandatory so that fileystems don't have to even think of dealing with ia_uid and ia_gid that --EWB Moved the test from inode_change_ok to notify_change Signed-off-by: Seth Forshee <redacted> Acked-by: Serge Hallyn <redacted> Signed-off-by: Eric W. Biederman <redacted> --- fs/attr.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/fs/attr.c b/fs/attr.c
index 25b24d0f6c88..dd723578ddce 100644
--- a/fs/attr.c
+++ b/fs/attr.c@@ -255,6 +255,17 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) return 0; + /* + * Verify that uid/gid changes are valid in the target + * namespace of the superblock. + */ + if (ia_valid & ATTR_UID && + !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + error = security_inode_setattr(dentry, attr); if (error) return error;
--
2.8.3