2019-02-09 20:38:24

by Kal Cutter Conley

Subject: [PATCH] net/packet: fix 4gb buffer limit due to overflow check

When calculating rb->frames_per_block * req->tp_block_nr the result
can overflow. Check it for overflow without limiting the total buffer
size to UINT_MAX.

This change fixes support for packet ring buffers >= UINT_MAX.
---
net/packet/af_packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d0945253f43b..d603a430378e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4291,7 +4291,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
if (unlikely(rb->frames_per_block == 0))
goto out;
- if (unlikely(req->tp_block_size > UINT_MAX / req->tp_block_nr))
+ if (unlikely(rb->frames_per_block > UINT_MAX / req->tp_block_nr))
goto out;
if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
req->tp_frame_nr))
--
2.20.1

2019-02-10 03:02:51

by David Miller

Subject: Re: [PATCH] net/packet: fix 4gb buffer limit due to overflow check

From: Kal Conley <[email protected]>
Date: Sat, 9 Feb 2019 21:37:00 +0100

> When calculating rb->frames_per_block * req->tp_block_nr the result
> can overflow. Check it for overflow without limiting the total buffer
> size to UINT_MAX.
>
> This change fixes support for packet ring buffers >= UINT_MAX.

Please resubmit with a proper signoff and also an appropriate Fixes:
tag.

2019-02-10 09:00:37

by Kal Cutter Conley

Subject: [PATCH v2] net/packet: fix 4gb buffer limit due to overflow check

When calculating rb->frames_per_block * req->tp_block_nr the result
can overflow. Check it for overflow without limiting the total buffer
size to UINT_MAX.

This change fixes support for packet ring buffers >= UINT_MAX.

Fixes: 8f8d28e4d6d8 ("net/packet: fix overflow in check for tp_frame_nr")
Signed-off-by: Kal Conley <[email protected]>
---
Changes in v2:
- Add Signed-off-by and Fixes tag

net/packet/af_packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 3b1a78906bc0..1cd1d83a4be0 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -4292,7 +4292,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
if (unlikely(rb->frames_per_block == 0))
goto out;
- if (unlikely(req->tp_block_size > UINT_MAX / req->tp_block_nr))
+ if (unlikely(rb->frames_per_block > UINT_MAX / req->tp_block_nr))
goto out;
if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
req->tp_frame_nr))
--
2.20.1

2019-02-12 19:29:01

by David Miller

Subject: Re: [PATCH v2] net/packet: fix 4gb buffer limit due to overflow check

From: Kal Conley <[email protected]>
Date: Sun, 10 Feb 2019 09:57:11 +0100

> When calculating rb->frames_per_block * req->tp_block_nr the result
> can overflow. Check it for overflow without limiting the total buffer
> size to UINT_MAX.
>
> This change fixes support for packet ring buffers >= UINT_MAX.
>
> Fixes: 8f8d28e4d6d8 ("net/packet: fix overflow in check for tp_frame_nr")
> Signed-off-by: Kal Conley <[email protected]>
> ---
> Changes in v2:
> - Add Signed-off-by and Fixes tag

Applied and queued up for -stable, thanks.