In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
pidfd: hold exec_update_lock around namespace ioctl<\/p>\n
The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem
\ncredentials ptrace access check before handing out a namespace file
\ndescriptor. The accompanying comment states that the code “mirrors nsfs
\nbehavior”, but, unlike the corresponding procfs paths, it does so without
\nholding the target task’s exec_update_lock.<\/p>\n
proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for
\nreading around the ptrace check and the namespace lookup, so that the
\ncredentials used for the access decision match those of the task when its
\nnamespace is read. Without it, a caller can pass the check against the
\ntarget’s old credentials and then read the namespace after the target has
\nexecve()’d a setuid binary and committed new credentials — accessing
\nnamespace information it should have been denied.<\/p>\n
Hold exec_update_lock for reading around the ptrace check and the
\nnamespace lookup so that pidfd truly mirrors nsfs behavior, as the comment
\nalready claims. open_namespace() itself runs outside the lock: once a
\nnamespace reference is obtained it carries its own refcount and is opened
\nwith the caller’s own credentials, so a concurrent execve() on the target
\ncan no longer affect the outcome.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
pidfd: hold exec_update_lock around namespace ioctl<\/p>\n
The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem
\ncredent<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21688","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21688","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21688"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21688"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21688"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}