Messages in this thread | | | From | Colin Ian King <> | Subject | re: mlxsw: spectrum: PTP: Support timestamping on Spectrum-1 - potential null ptr dereference | Date | Tue, 2 Jul 2019 16:01:49 +0100 |
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Hi,
Static analysis with Coverity on today's linux-next has found a potential null pointer dereference bug with the following commit:
commit d92e4e6e33c8b19635be70fb8935b627d2e4f8fe Author: Petr Machata <petrm@mellanox.com> Date: Sun Jun 30 09:04:56 2019 +0300
mlxsw: spectrum: PTP: Support timestamping on Spectrum-1
In function: mlxsw_sp1_ptp_packet_finish the offending code is as follows:
/* Between capturing the packet and finishing it, there is a window of * opportunity for the originating port to go away (e.g. due to a * split). Also make sure the SKB device reference is still valid. */ mlxsw_sp_port = mlxsw_sp->ports[local_port]; if (!mlxsw_sp_port && (!skb->dev || skb->dev == mlxsw_sp_port->dev)) { dev_kfree_skb_any(skb); return; }
If mlxsw_sp_port is null and skb->dev is not-null then the comparison "skb->dev == mlxsw_sp_port->dev" ends up with a null pointer dereference.
I think the if statement should be:
if (mlxsw_sp_port && (!skb->dev || skb->dev == mlxsw_sp_port->dev))
..but I'm not 100% sure as I may be missing something a bit more subtle here.
Colin
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