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[3/5] net/packet: fix overflow in check for tp_frame_nr

Message ID 69c847e0cfbf26c38d6dfa6289ce5ca830866b42.1490709552.git.andreyknvl@google.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Andrey Konovalov March 28, 2017, 2 p.m. UTC 
When calculating rb->frames_per_block * req->tp_block_nr the result
can overflow.

Add a check that tp_block_size * tp_block_nr <= UINT_MAX.

Since frames_per_block <= tp_block_size, the expression would
never overflow.

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

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 506348abdf2f..c5c43fff8c01 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4197,6 +4197,9 @@  static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
 			goto out;
 		if (unlikely(req->tp_frame_size == 0))
 			goto out;
+		if (unlikely((u64)req->tp_block_size * req->tp_block_nr >
+					UINT_MAX))
+			goto out;
 
 		if (unlikely(!PAGE_ALIGNED(req->tp_block_size)))
 			goto out;