Re: [PATCH net-next] packet: fix panic in __packet_set_timestamp on tpacket_v3 in tx mode

[Daniel Borkmann]

On 01/05/2017 07:27 PM, Eric Dumazet wrote:

On Thu, 2017-01-05 at 02:34 +0100, Daniel Borkmann wrote:

[...]

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 7e39087..ddbda25 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -481,6 +481,9 @@ static __u32 __packet_set_timestamp(struct packet_sock *po, 
void *frame,
                h.h2->tp_nsec = ts.tv_nsec;
                break;
        case TPACKET_V3:
+               h.h3->tp_sec = ts.tv_sec;
+               h.h3->tp_nsec = ts.tv_nsec;
+               break;
        default:
                WARN(1, "TPACKET version not supported.\n");
                BUG();

Gosh. Can we also replace this BUG() into something less aggressive ?

There are currently 5 of these WARN() + BUG() constructs and 1 BUG()-only
for the 'default' TPACKET version spread all over af_packet, so probably
makes sense to rather make all of them less aggressive.

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 
b9e1a13b4ba36a0bc7edf6a8c2c116c7d48c970c..0c0d268544787dcbef6601c5014e7d3836d16f96
 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -476,9 +476,11 @@ static __u32 __packet_set_timestamp(struct packet_sock 
*po, void *frame,
                h.h2->tp_nsec = ts.tv_nsec;
                break;
        case TPACKET_V3:
+               h.h3->tp_sec = ts.tv_sec;
+               h.h3->tp_nsec = ts.tv_nsec;
+               break;
        default:
-               WARN(1, "TPACKET version not supported.\n");
-               BUG();
+               pr_err_once("TPACKET version %u not supported.\n", 
po->tp_version);
        }

        /* one flush is safe, as both fields always lie on the same cacheline */