The patch titled
Subject: mm-add-an-f_seal_future_write-seal-to-memfd-fix-2
has been added to the -mm tree. Its filename is
mm-add-an-f_seal_future_write-seal-to-memfd-fix-2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-add-an-f_seal_future_write-seal-to-memfd-fix-2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-add-an-f_seal_future_write-seal-to-memfd-fix-2.patch
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------------------------------------------------------
From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>
Subject: mm-add-an-f_seal_future_write-seal-to-memfd-fix-2
v4
Link: http://lkml.kernel.org/r/20181122230906.GA198127@xxxxxxxxxx
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Suggested-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/shmem.c~mm-add-an-f_seal_future_write-seal-to-memfd-fix-2
+++ a/mm/shmem.c
@@ -2123,20 +2123,22 @@ static int shmem_mmap(struct file *file,
{
struct shmem_inode_info *info = SHMEM_I(file_inode(file));
- /*
- * New PROT_READ and MAP_SHARED mmaps are not allowed when "future
- * write" seal active.
- */
- if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE) &&
- (info->seals & F_SEAL_FUTURE_WRITE))
- return -EPERM;
- /*
- * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED read-only
- * mapping, take care to not allow mprotect to revert protections.
- */
- if (info->seals & F_SEAL_FUTURE_WRITE)
+ if (info->seals & F_SEAL_FUTURE_WRITE) {
+ /*
+ * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
+ * "future write" seal active.
+ */
+ if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
+ return -EPERM;
+
+ /*
+ * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED
+ * read-only mapping, take care to not allow mprotect to revert
+ * protections.
+ */
vma->vm_flags &= ~(VM_MAYWRITE);
+ }
file_accessed(file);
vma->vm_ops = &shmem_vm_ops;
_
Patches currently in -mm which might be from joel@xxxxxxxxxxxxxxxxx are
mm-treewide-remove-unused-address-argument-from-pte_alloc-functions-v2.patch
mm-speed-up-mremap-by-20x-on-large-regions-v5.patch
mm-speed-up-mremap-by-20x-on-large-regions-v5-fix.patch
mm-select-have_move_pmd-in-x86-for-faster-mremap.patch
mm-add-an-f_seal_future_write-seal-to-memfd.patch
mm-add-an-f_seal_future_write-seal-to-memfd-fix.patch
mm-add-an-f_seal_future_write-seal-to-memfd-fix-2.patch
selftests-memfd-add-tests-for-f_seal_future_write-seal.patch
selftests-memfd-add-tests-for-f_seal_future_write-seal-fix.patch
