[v2,2/3] mm: update seal_check_[future_]write() to include F_SEAL_WRITE as well
Commit Message
Check for F_SEAL_WRITE as well for which the precise same logic can
reasonably be applied, however so far this code will simply not be run as
the mapping_map_writable() call occurs before shmem_mmap() or
hugetlbfs_file_mmap() and thus would error out in the case of a read-only
shared mapping before the logic could be applied.
This therefore has no impact until the following patch which changes the
order in which the *_mmap() functions are called.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
---
fs/hugetlbfs/inode.c | 2 +-
include/linux/mm.h | 13 +++++++------
mm/shmem.c | 2 +-
3 files changed, 9 insertions(+), 8 deletions(-)
@@ -135,7 +135,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
vma->vm_ops = &hugetlb_vm_ops;
- ret = seal_check_future_write(info->seals, vma);
+ ret = seal_check_write(info->seals, vma);
if (ret)
return ret;
@@ -3784,16 +3784,17 @@ static inline void mem_dump_obj(void *object) {}
#endif
/**
- * seal_check_future_write - Check for F_SEAL_FUTURE_WRITE flag and handle it
+ * seal_check_write - Check for F_SEAL_WRITE or F_SEAL_FUTURE_WRITE flag and
+ * handle it.
* @seals: the seals to check
* @vma: the vma to operate on
*
- * Check whether F_SEAL_FUTURE_WRITE is set; if so, do proper check/handling on
- * the vma flags. Return 0 if check pass, or <0 for errors.
+ * Check whether F_SEAL_WRITE or F_SEAL_FUTURE_WRITE are set; if so, do proper
+ * check/handling on the vma flags. Return 0 if check pass, or <0 for errors.
*/
-static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
+static inline int seal_check_write(int seals, struct vm_area_struct *vma)
{
- if (seals & F_SEAL_FUTURE_WRITE) {
+ if (seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
/*
* New PROT_WRITE and MAP_SHARED mmaps are not allowed when
* "future write" seal active.
@@ -3802,7 +3803,7 @@ static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
return -EPERM;
/*
- * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
+ * Since an F_SEAL_[FUTURE_]WRITE sealed memfd can be mapped as
* MAP_SHARED and read-only, take care to not allow mprotect to
* revert protections on such mappings. Do this only for shared
* mappings. For private mappings, don't need to mask
@@ -2325,7 +2325,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
struct shmem_inode_info *info = SHMEM_I(inode);
int ret;
- ret = seal_check_future_write(info->seals, vma);
+ ret = seal_check_write(info->seals, vma);
if (ret)
return ret;