From: Jeff Xu <[email protected]> Two utilities to be used later.
can_modify_mm: checks sealing flags for given memory range. can_modify_vma: checks sealing flags for given vma. Signed-off-by: Jeff Xu <[email protected]> --- include/linux/mm.h | 18 ++++++++++++++++++ mm/mseal.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 3d1120570de5..2435acc1f44f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3339,6 +3339,12 @@ static inline unsigned long vma_seals(struct vm_area_struct *vma) return (vma->vm_seals & MM_SEAL_ALL); } +extern bool can_modify_mm(struct mm_struct *mm, unsigned long start, + unsigned long end, unsigned long checkSeals); + +extern bool can_modify_vma(struct vm_area_struct *vma, + unsigned long checkSeals); + #else static inline bool check_vma_seals_mergeable(unsigned long vm_seals1) { @@ -3349,6 +3355,18 @@ static inline unsigned long vma_seals(struct vm_area_struct *vma) { return 0; } + +static inline bool can_modify_mm(struct mm_struct *mm, unsigned long start, + unsigned long end, unsigned long checkSeals) +{ + return true; +} + +static inline bool can_modify_vma(struct vm_area_struct *vma, + unsigned long checkSeals) +{ + return true; +} #endif /* These take the mm semaphore themselves */ diff --git a/mm/mseal.c b/mm/mseal.c index 13bbe9ef5883..d12aa628ebdc 100644 --- a/mm/mseal.c +++ b/mm/mseal.c @@ -26,6 +26,44 @@ static bool can_do_mseal(unsigned long types, unsigned long flags) return true; } +/* + * check if a vma is sealed for modification. + * return true, if modification is allowed. + */ +bool can_modify_vma(struct vm_area_struct *vma, + unsigned long checkSeals) +{ + if (checkSeals & vma_seals(vma)) + return false; + + return true; +} + +/* + * Check if the vmas of a memory range are allowed to be modified. + * the memory ranger can have a gap (unallocated memory). + * return true, if it is allowed. + */ +bool can_modify_mm(struct mm_struct *mm, unsigned long start, unsigned long end, + unsigned long checkSeals) +{ + struct vm_area_struct *vma; + + VMA_ITERATOR(vmi, mm, start); + + if (!checkSeals) + return true; + + /* going through each vma to check. */ + for_each_vma_range(vmi, vma, end) { + if (!can_modify_vma(vma, checkSeals)) + return false; + } + + /* Allow by default. */ + return true; +} + /* * Check if a seal type can be added to VMA. */ -- 2.43.0.472.g3155946c3a-goog
