[PATCH 2/5] net/packet: add explicit checks for tp_frame_size

[Andrey Konovalov]

tp_frame_size can't be 0 or be larger than tp_block_size.

As a result the check for frames_per_block == 0 is not needed any more.

Also do explicit checks for tp_block_size, instead of casting to int.

Signed-off-by: Andrey Konovalov <andreyk...@google.com>
---
 net/packet/af_packet.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2323ee35dc09..506348abdf2f 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4188,8 +4188,16 @@ static int packet_set_ring(struct sock *sk, union 
tpacket_req_u *req_u,
                }
 
                err = -EINVAL;
-               if (unlikely((int)req->tp_block_size <= 0))
+
+               if (unlikely(req->tp_block_size > INT_MAX))
+                       goto out;
+               if (unlikely(req->tp_block_size == 0))
+                       goto out;
+               if (unlikely(req->tp_frame_size > req->tp_block_size))
                        goto out;
+               if (unlikely(req->tp_frame_size == 0))
+                       goto out;
+
                if (unlikely(!PAGE_ALIGNED(req->tp_block_size)))
                        goto out;
                if (po->tp_version >= TPACKET_V3 &&
@@ -4203,8 +4211,6 @@ static int packet_set_ring(struct sock *sk, union 
tpacket_req_u *req_u,
                        goto out;
 
                rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
-               if (unlikely(rb->frames_per_block == 0))
-                       goto out;
                if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
                                        req->tp_frame_nr))
                        goto out;
-- 
2.12.2.564.g063fe858b8-goog