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authorDan Williams <dan.j.williams@intel.com>2016-12-06 17:03:35 -0800
committerDan Williams <dan.j.williams@intel.com>2016-12-06 17:42:37 -0800
commit325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c (patch)
treed71d337b3a5b9858907c6a4a0797ced074302590 /drivers
parenta7de92dac9f0dbf01deb56fe1d661d7baac097e1 (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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/dax/dax.c2
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;