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| author |   Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 07:55:16 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-08-20 07:55:16 -0700 |
| commit | dc617f29dbe5ef0c8ced65ce62c464af1daaab3d (patch) | |
| tree | 3596eb0d334f04f87088c735748bba8e66a71cad /mm/mmap.c | |
| parent | mm: set S_SWAPFILE on blockdev swap devices (diff) | |
| download | wireguard-linux-dc617f29dbe5ef0c8ced65ce62c464af1daaab3d.tar.xz wireguard-linux-dc617f29dbe5ef0c8ced65ce62c464af1daaab3d.zip | |
vfs: don't allow writes to swap files
Don't let userspace write to an active swap file because the kernel
effectively has a long term lease on the storage and things could get
seriously corrupted if we let this happen.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 7e8c3e8ae75f..6bc21fca20bc 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1483,8 +1483,12 @@ unsigned long do_mmap(struct file *file, unsigned long addr, case MAP_SHARED_VALIDATE: if (flags & ~flags_mask) return -EOPNOTSUPP; - if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) - return -EACCES; + if (prot & PROT_WRITE) { + if (!(file->f_mode & FMODE_WRITE)) + return -EACCES; + if (IS_SWAPFILE(file->f_mapping->host)) + return -ETXTBSY; + } /* * Make sure we don't allow writing to an append-only |