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authorJeff Mahoney <jeffm@suse.com>2016-07-05 17:32:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-10 11:49:27 +0200
commited5c955e31ff07fa74738b6e0d94c5c17ebbf7c7 (patch)
treeb2730b32103dd91d1b64905fb6397a5b1828219d /fs/ecryptfs
parentae159a027893a8bdeaab0c5f863ca6e57b4468d3 (diff)
ecryptfs: don't allow mmap when the lower fs doesn't support it
commit f0fe970df3838c202ef6c07a4c2b36838ef0a88b upstream. 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. CVE-2016-1583 Signed-off-by: Jeff Mahoney <jeffm@suse.com> [tyhicks: clean up f_op check by using ecryptfs_file_to_lower()] Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ecryptfs')
-rw-r--r--fs/ecryptfs/file.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index feef8a9c4de7..11309683d65f 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -170,6 +170,19 @@ out:
return rc;
}
+static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct file *lower_file = ecryptfs_file_to_lower(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 (!lower_file->f_op->mmap)
+ return -ENODEV;
+ return generic_file_mmap(file, vma);
+}
+
/**
* ecryptfs_open
* @inode: inode speciying file to open
@@ -364,7 +377,7 @@ 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,