Re: [net] ipv6: sr: fix missing sk_buff release in seg6_input_core

[Simon Horman]

On Fri, May 17, 2024 at 06:45:41PM +0200, Andrea Mayer wrote:
> The seg6_input() function is responsible for adding the SRH into a
> packet, delegating the operation to the seg6_input_core(). This function
> uses the skb_cow_head() to ensure that there is sufficient headroom in
> the sk_buff for accommodating the link-layer header.
> In the event that the skb_cow_header() function fails, the
> seg6_input_core() catches the error but it does not release the sk_buff,
> which will result in a memory leak.
> 
> This issue was introduced in commit af3b5158b89d ("ipv6: sr: fix BUG due
> to headroom too small after SRH push") and persists even after commit
> 7a3f5b0de364 ("netfilter: add netfilter hooks to SRv6 data plane"),
> where the entire seg6_input() code was refactored to deal with netfilter
> hooks.
> 
> The proposed patch addresses the identified memory leak by requiring the
> seg6_input_core() function to release the sk_buff in the event that
> skb_cow_head() fails.
> 
> Fixes: af3b5158b89d ("ipv6: sr: fix BUG due to headroom too small after SRH push")
> Signed-off-by: Andrea Mayer <andrea.mayer@xxxxxxxxxxx>

Reviewed-by: Simon Horman <horms@xxxxxxxxxx>