diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2016-12-06 17:03:35 -0800 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2016-12-06 17:42:37 -0800 |
| commit | 325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c (patch) | |
| tree | d71d337b3a5b9858907c6a4a0797ced074302590 | |
| parent | a7de92dac9f0dbf01deb56fe1d661d7baac097e1 (diff) | |
device-dax: fix private mapping restriction, permit read-only
Hugh notes in response to commit 4cb19355ea19 "device-dax: fail all
private mapping attempts":
"I think that is more restrictive than you intended: haven't tried, but I
believe it rejects a PROT_READ, MAP_SHARED, O_RDONLY fd mmap, leaving no
way to mmap /dev/dax without write permission to it."
Indeed it does restrict read-only mappings, switch to checking
VM_MAYSHARE, not VM_SHARED.
Cc: <stable@vger.kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pawel Lebioda <pawel.lebioda@intel.com>
Fixes: 4cb19355ea19 ("device-dax: fail all private mapping attempts")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| -rw-r--r-- | drivers/dax/dax.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 3d94ff20fdca..286447a83dab 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -271,7 +271,7 @@ static int check_vma(struct dax_dev *dax_dev, struct vm_area_struct *vma, return -ENXIO; /* prevent private mappings from being established */ - if ((vma->vm_flags & VM_SHARED) != VM_SHARED) { + if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) { dev_info(dev, "%s: %s: fail, attempted private mapping\n", current->comm, func); return -EINVAL; |