diff options
Diffstat (limited to 'mm/mremap.c')
| -rw-r--r-- | mm/mremap.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index f5aba752d35f..5f96bc5ee918 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -902,7 +902,25 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, if ((mm->map_count + 2) >= sysctl_max_map_count - 3) return -ENOMEM; + /* + * In mremap_to(). + * Move a VMA to another location, check if src addr is sealed. + * + * Place can_modify_mm here because mremap_to() + * does its own checking for address range, and we only + * check the sealing after passing those checks. + * + * can_modify_mm assumes we have acquired the lock on MM. + */ + if (unlikely(!can_modify_mm(mm, addr, addr + old_len))) + return -EPERM; + if (flags & MREMAP_FIXED) { + /* + * In mremap_to(). + * VMA is moved to dst address, and munmap dst first. + * do_munmap will check if dst is sealed. + */ ret = do_munmap(mm, new_addr, new_len, uf_unmap_early); if (ret) goto out; @@ -1062,6 +1080,19 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, } /* + * Below is shrink/expand case (not mremap_to()) + * Check if src address is sealed, if so, reject. + * In other words, prevent shrinking or expanding a sealed VMA. + * + * Place can_modify_mm here so we can keep the logic related to + * shrink/expand together. + */ + if (unlikely(!can_modify_mm(mm, addr, addr + old_len))) { + ret = -EPERM; + goto out; + } + + /* * Always allow a shrinking remap: that just unmaps * the unnecessary pages.. * do_vmi_munmap does all the needed commit accounting, and |