path: root/mm/mmap.c
diff options
authorDmitry Safonov <dima@arista.com>2020-12-14 19:08:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:41 -0800
commitcd544fd1dc9293c6702fab6effa63dac1cc67e99 (patch)
tree5af943ffbac575fdf9576bc4ef772fa388efd3da /mm/mmap.c
parentmm/mremap: for MREMAP_DONTUNMAP check security_vm_enough_memory_mm() (diff)
mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio
As kernel expect to see only one of such mappings, any further operations on the VMA-copy may be unexpected by the kernel. Maybe it's being on the safe side, but there doesn't seem to be any expected use-case for this, so restrict it now. Link: https://lkml.kernel.org/r/20201013013416.390574-4-dima@arista.com Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Signed-off-by: Dmitry Safonov <dima@arista.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Geffon <bgeffon@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 5c8b4485860d..8950c20239a0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3405,10 +3405,14 @@ static const char *special_mapping_name(struct vm_area_struct *vma)
return ((struct vm_special_mapping *)vma->vm_private_data)->name;
-static int special_mapping_mremap(struct vm_area_struct *new_vma)
+static int special_mapping_mremap(struct vm_area_struct *new_vma,
+ unsigned long flags)
struct vm_special_mapping *sm = new_vma->vm_private_data;
+ if (flags & MREMAP_DONTUNMAP)
+ return -EINVAL;
if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
return -EFAULT;