Re: [PATCH v2 0/3] Fix several use after free bugs

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On Wed. 20 Jan 2021 à 18:09, Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> wrote:
> This series fix three bugs which all have the same root cause.
>
> When calling netif_rx(skb) and its variants, the skb will eventually
> get consumed (or freed) and thus it is unsafe to dereference it after
> the call returns.
>
> This remark especially applies to any variable with aliases the skb
> memory which is the case of the can(fd)_frame.
>
> The pattern is as this:
>     skb = alloc_can_skb(dev, &cf);
>     /* Do stuff */
>     netif_rx(skb);
>     stats->rx_bytes += cf->len;
>
> Increasing the stats should be done *before* the call to netif_rx()
> while the skb is still safe to use.
>
>
> Changes since v1:
>   - fix a silly typo in patch 2/3 (variable len was declared twice...)
>
>
> Vincent Mailhol (3):
>   can: dev: can_restart: fix use after free bug
>   can: vxcan: vxcan_xmit: fix use after free bug
>   can: peak_usb: fix use after free bugs
>
>  drivers/net/can/dev/dev.c                  | 4 ++--
>  drivers/net/can/usb/peak_usb/pcan_usb_fd.c | 8 ++++----
>  drivers/net/can/vxcan.c                    | 6 ++++--
>  3 files changed, 10 insertions(+), 8 deletions(-)
>
>
> base-commit: 1105592cb8fdfcc96f2c9c693ff4106bac5fac7c
> --
> 2.26.2

And of course, I just saw Marc comments just after sending the v2...
Please ignore this message, there will be a v3 rebased on net/master.

And sorry for the noise.


Yours sincerely,
Vincent



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