diff options
| author |   Dmitry Safonov <dima@arista.com> | 2020-12-14 19:08:13 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 12:13:41 -0800 |
| commit | cd544fd1dc9293c6702fab6effa63dac1cc67e99 (patch) | |
| tree | 5af943ffbac575fdf9576bc4ef772fa388efd3da | |
| parent | mm/mremap: for MREMAP_DONTUNMAP check security_vm_enough_memory_mm() (diff) | |
| download | linux-dev-cd544fd1dc9293c6702fab6effa63dac1cc67e99.tar.xz linux-dev-cd544fd1dc9293c6702fab6effa63dac1cc67e99.zip | |
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>
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 2 | ||||
| -rw-r--r-- | fs/aio.c | 5 | ||||
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/mmap.c | 6 | ||||
| -rw-r--r-- | mm/mremap.c | 2 |
5 files changed, 12 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c index 0daf2f1cf7a8..e916646adc69 100644 --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c +++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c @@ -1458,7 +1458,7 @@ static int pseudo_lock_dev_release(struct inode *inode, struct file *filp) return 0; } -static int pseudo_lock_dev_mremap(struct vm_area_struct *area) +static int pseudo_lock_dev_mremap(struct vm_area_struct *area, unsigned long flags) { /* Not supported */ return -EINVAL; @@ -324,13 +324,16 @@ static void aio_free_ring(struct kioctx *ctx) } } -static int aio_ring_mremap(struct vm_area_struct *vma) +static int aio_ring_mremap(struct vm_area_struct *vma, unsigned long flags) { struct file *file = vma->vm_file; struct mm_struct *mm = vma->vm_mm; struct kioctx_table *table; int i, res = -EINVAL; + if (flags & MREMAP_DONTUNMAP) + return -EINVAL; + spin_lock(&mm->ioctx_lock); rcu_read_lock(); table = rcu_dereference(mm->ioctx_table); diff --git a/include/linux/mm.h b/include/linux/mm.h index 1d8e84bf718a..dacc889744b1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -558,7 +558,7 @@ struct vm_operations_struct { void (*open)(struct vm_area_struct * area); void (*close)(struct vm_area_struct * area); int (*split)(struct vm_area_struct * area, unsigned long addr); - int (*mremap)(struct vm_area_struct * area); + int (*mremap)(struct vm_area_struct *area, unsigned long flags); vm_fault_t (*fault)(struct vm_fault *vmf); vm_fault_t (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size); 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; diff --git a/mm/mremap.c b/mm/mremap.c index 90ff09c09e84..366b3dea992c 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -534,7 +534,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, if (moved_len < old_len) { err = -ENOMEM; } else if (vma->vm_ops && vma->vm_ops->mremap) { - err = vma->vm_ops->mremap(new_vma); + err = vma->vm_ops->mremap(new_vma, flags); } if (unlikely(err)) { |