Описание
In the Linux kernel, the following vulnerability has been resolved:
mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free
__GFP_ZEROTAGS semantics are currently a bit weird, but effectively this flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN.
If we run with init_on_free, we will zero out pages during __free_pages_prepare(), to skip zeroing on the allocation path.
However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will consequently not only skip clearing page content, but also skip clearing tag memory.
Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that will get mapped to user space through set_pte_at() later: set_pte_at() and friends will detect that the tags have not been initialized yet (PG_mte_tagged not set), and initialize them.
However, for the huge zero folio, which will be mapped through a PMD marked as special, this initialization will not be performed, ending up exposing whatever tags w
EPSS
Дефекты
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free __GFP_ZEROTAGS semantics are currently a bit weird, but effectively this flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN. If we run with init_on_free, we will zero out pages during __free_pages_prepare(), to skip zeroing on the allocation path. However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will consequently not only skip clearing page content, but also skip clearing tag memory. Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that will get mapped to user space through set_pte_at() later: set_pte_at() and friends will detect that the tags have not been initialized yet (PG_mte_tagged not set), and initialize them. However, for the huge zero folio, which will be mapped through a PMD marked as special, this initialization will not be performed, ending up exposing whatever tags were...
In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free __GFP_ZEROTAGS semantics are currently a bit weird, but effectively this flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN. If we run with init_on_free, we will zero out pages during __free_pages_prepare(), to skip zeroing on the allocation path. However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will consequently not only skip clearing page content, but also skip clearing tag memory. Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that will get mapped to user space through set_pte_at() later: set_pte_at() and friends will detect that the tags have not been initialized yet (PG_mte_tagged not set), and initialize them. However, for the huge zero folio, which will be mapped through a PMD marked as special, this initialization will not be performed, ending up exposing whatever tags were...
In the Linux kernel, the following vulnerability has been resolved: m ...
In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: fix initialization of tags of the huge zero folio with init_on_free __GFP_ZEROTAGS semantics are currently a bit weird, but effectively this flag is only ever set alongside __GFP_ZERO and __GFP_SKIP_KASAN. If we run with init_on_free, we will zero out pages during __free_pages_prepare(), to skip zeroing on the allocation path. However, when allocating with __GFP_ZEROTAG set, post_alloc_hook() will consequently not only skip clearing page content, but also skip clearing tag memory. Not clearing tags through __GFP_ZEROTAGS is irrelevant for most pages that will get mapped to user space through set_pte_at() later: set_pte_at() and friends will detect that the tags have not been initialized yet (PG_mte_tagged not set), and initialize them. However, for the huge zero folio, which will be mapped through a PMD marked as special, this initialization will not be performed, ending up exposing whatever tag...
EPSS