In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ARM: 9485\/1: mm: acquire mmap write lock around show_pte() for user faults<\/p>\n
When CONFIG_DEBUG_USER=y, and cmdline “user_debug=31” is set,
\na user fault may trigger show_pte() without any lock.
\nIf another thread in the same process concurrently calls munmap(),
\nthe page table pages may be freed while show_pte() is still traversing
\nthem, causing a use-after-free in show_pte().<\/p>\n
If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
\nof PMD are freed when show_pte() is running.<\/p>\n
Acquire mmap_write_lock() around show_pte() for user faults to fix the
\ncontention.<\/p>\n
For user faults, additionally restrict that show_pte() is called only
\nwhen the addr is a user-space address (addr mm only protects the virtual memory of user address space,
\nfurthermore, dumping the page tables of a kernel-space address for user
\nfaults is unnecessary and may have security implications.<\/p>\n
Keep everything unchanged for kernel faults, because the kernel is
\nalready in the “oops” state, acquiring a lock may risk a deadlock.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
ARM: 9485\/1: mm: acquire mmap write lock around show_pte() for user faults<\/p>\n
When CONFIG_DEBUG_USER=y, and cmdline “user_debug=31” i<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25712","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25712","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=25712"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25712"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25712"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}