relay: prevent integer overflow in relay_open()

"subbuf_size" and "n_subbufs" come from the user and they need to be
capped to prevent an integer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/kernel/relay.c b/kernel/relay.c
index 4335e1d7ee2d722c94507775b4c8d7c3cd21d567..ab56a1764d4db8c6a5136cd3b636dc330648783b 100644 (file)
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -164,10 +164,14 @@ depopulate:
  */
 static struct rchan_buf *relay_create_buf(struct rchan *chan)
 {
-       struct rchan_buf *buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
-       if (!buf)
+       struct rchan_buf *buf;
+
+       if (chan->n_subbufs > UINT_MAX / sizeof(size_t *))
                return NULL;
 
+       buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
+       if (!buf)
+               return NULL;
        buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
        if (!buf->padding)
                goto free_buf;
@@ -574,6 +578,8 @@ struct rchan *relay_open(const char *base_filename,
 
        if (!(subbuf_size && n_subbufs))
                return NULL;
+       if (subbuf_size > UINT_MAX / n_subbufs)
+               return NULL;
 
        chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
        if (!chan)