From: Jeff Mahoney <jeffm@xxxxxxxx>
There are legitimate reasons to disallow mmap on certain files, notably
in sysfs or procfs. We shouldn't emulate mmap support on file systems
that don't offer support natively.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/ecryptfs/file.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 7000b96..4aaa656 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -169,6 +169,20 @@ out:
return rc;
}
+
+static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct dentry *dentry = ecryptfs_dentry_to_lower(file_dentry(file));
+ /*
+ * Don't allow mmap on top of file systems that don't support it
+ * natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
+ * allows recursive mounting, this will need to be extended.
+ */
+ if (!d_inode(dentry)->i_fop->mmap)
+ return -ENODEV;
+ return generic_file_mmap(file, vma);
+}
+
/**
* ecryptfs_open
* @inode: inode speciying file to open
@@ -403,7 +417,7 @@ const struct file_operations ecryptfs_main_fops = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ecryptfs_compat_ioctl,
#endif
- .mmap = generic_file_mmap,
+ .mmap = ecryptfs_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
--
2.7.1
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