search for: maybe_mkwrit

...ory.c --- linux-2.6/mm/memory.c 2006-09-01 12:50:24.000000000 +0200 +++ linux-2.6-patched/mm/memory.c 2006-09-01 12:50:24.000000000 +0200 @@ -1558,6 +1558,7 @@ static int do_wp_page(struct mm_struct * flush_cache_page(vma, address, pte_pfn(orig_pte)); entry = pte_mkyoung(orig_pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + page_check_writable(old_page, entry); ptep_set_access_flags(vma, address, page_table, entry, 1); update_mmu_cache(vma, address, entry); lazy_mmu_prot_update(entry); @@ -1607,6 +1608,7 @@ gotten: flush_cache_page(vma, address, pte_pfn(orig_pte)); entry =...

...ory.c --- linux-2.6/mm/memory.c 2006-09-01 12:50:24.000000000 +0200 +++ linux-2.6-patched/mm/memory.c 2006-09-01 12:50:24.000000000 +0200 @@ -1558,6 +1558,7 @@ static int do_wp_page(struct mm_struct * flush_cache_page(vma, address, pte_pfn(orig_pte)); entry = pte_mkyoung(orig_pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); + page_check_writable(old_page, entry); ptep_set_access_flags(vma, address, page_table, entry, 1); update_mmu_cache(vma, address, entry); lazy_mmu_prot_update(entry); @@ -1607,6 +1608,7 @@ gotten: flush_cache_page(vma, address, pte_pfn(orig_pte)); entry =...

...@@ split_fallthrough: */ mark_page_accessed(page); } -unlock: pte_unmap_unlock(ptep, ptl); out: return page; @@ -1489,17 +1507,13 @@ int __get_user_pages(struct task_struct * The VM_FAULT_WRITE bit tells us that * do_wp_page has broken COW when necessary, * even if maybe_mkwrite decided not to set - * pte_write. We can thus safely do subsequent - * page lookups as if they were reads. But only - * do so when looping for pte_write is futile: - * in some cases userspace may also be wanting - * to write to the gotten user page, which a - * read fault h...

On Tue, 25 Oct 2016 10:06:12 +0200 Christian Anthon <anthon at rth.dk> wrote: > What is the best approach on centos 6 to mitigate the problem is > officially patched? As far as I can tell Centos 6 is vulnerable to > attacks using ptrace. I can confirm that c6 is vulnerable, we're running a patched kernel (local build) using a rhel6 adaptation of the upstream fix. Ask

...into driver's .fault->ttm_bo_vm_fault_reserved->vmf_insert_pfn_prot->insert_pfn. > The insert_pfn will establish the pte entry. However the vmf_insert_pfn_prot > pass false @mkwrite to insert_pfn by default and so insert_pfn could not make > the pfn writable and it do not call maybe_mkwrite(pte_mkdirty(entry), vma) > to clear the PTE_RDONLY bit. So the pte entry is actually write protection for mmu. > So when the first fault return and re-execute the store instruction the second > fault happen again. And in second fault it just only do pte_mkdirty(entry) which > clear the...

Greetings, after Carsten pitched CMM2 on the kvm mini summit here is a repost of version 5 of the guest page hinting patches. The code is still the same but has been adapted to the latest git level. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.

Greetings, after Carsten pitched CMM2 on the kvm mini summit here is a repost of version 5 of the guest page hinting patches. The code is still the same but has been adapted to the latest git level. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.

After way to many months here is the fifth version of the guest page hinting patches. Compared to version four a few improvements have been added: - Avoid page_host_discards() calls outside of page-states.h - The discard list is now implemented via the page_free_discarded hook and architecture specific code. - PG_state_change page flag has been replaced with architecture specficic

After way to many months here is the fifth version of the guest page hinting patches. Compared to version four a few improvements have been added: - Avoid page_host_discards() calls outside of page-states.h - The discard list is now implemented via the page_free_discarded hook and architecture specific code. - PG_state_change page flag has been replaced with architecture specficic

I''m sure everyone has seen the drop of VMI patches for Linux at this point, but just in case, the link is included below. I''ve read this version of the VMI spec and have made my way through most of the patches. While I wasn''t really that impressed with the first spec wrt Xen, the second version seems to be much more palatable. Specifically, the code inlining and