1 files changed, 10 insertions, 0 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ea8237513dfa..24ea19cfe07e 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1317,6 +1317,16 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
         unsigned reqsize;
         unsigned int hash;
 
+        /*
+         * Require sane minimum read buffer - that has capacity for fixed part
+         * of any request header + negotated max_write room for data. If the
+         * requirement is not satisfied return EINVAL to the filesystem server
+         * to indicate that it is not following FUSE server/client contract.
+         * Don't dequeue / abort any request.
+         */
+        if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 4096 + fc->max_write))
+                return -EINVAL;
+
  restart:
         spin_lock(&fiq->waitq.lock);
         err = -EAGAIN;