diff options
| author | Pedro Falcato <pedro.falcato@gmail.com> | 2024-08-17 01:18:31 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-03 21:15:41 -0700 |
| commit | 38075679b5f157eeacd46c900e9cfc684bdbc167 (patch) | |
| tree | a808ff314a885cf5e523c22b064637e983fba023 | |
| parent | 4a2dd02b09160ee43f96c759fafa7b56dfc33816 (diff) | |
mm/mremap: replace can_modify_mm with can_modify_vma
Delegate all can_modify checks to the proper places. Unmap checks are
done in do_unmap (et al). The source VMA check is done purposefully
before unmapping, to keep the original mseal semantics.
Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-4-d8d2e037df30@gmail.com
Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/mremap.c | 32 |
1 files changed, 6 insertions, 26 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index e7ae140fc640..24712f8dbb6b 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -902,19 +902,6 @@ 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(). @@ -1052,6 +1039,12 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, goto out; } + /* Don't allow remapping vmas when they have already been sealed */ + if (!can_modify_vma(vma)) { + ret = -EPERM; + goto out; + } + if (is_vm_hugetlb_page(vma)) { struct hstate *h __maybe_unused = hstate_vma(vma); @@ -1080,19 +1073,6 @@ 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 |