1 files changed, 9 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index d3c190c35fcc..87f97ba90ad1 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1656,6 +1656,15 @@ struct file *do_filp_open(int dfd, const char *pathname,
         int will_write;
         int flag = open_to_namei_flags(open_flag);
 
+        /*
+         * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
+         * check for O_DSYNC if the need any syncing at all we enforce it's
+         * always set instead of having to deal with possibly weird behaviour
+         * for malicious applications setting only __O_SYNC.
+         */
+        if (open_flag & __O_SYNC)
+                open_flag |= O_DSYNC;
+
         if (!acc_mode)
                 acc_mode = MAY_OPEN | ACC_MODE(flag);