ipv6: sr: fix missing sk_buff release in seg6_input_core

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix missing sk_buff release in seg6_input_core 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.

References

• https://git.kernel.org/stable/c/e8688218e38111ace457509d8f0cad75f79c1a7a
• https://git.kernel.org/stable/c/8f1fc3b86eaea70be6abcae2e9aa7e7b99453864
• https://git.kernel.org/stable/c/f4df8c7670a73752201cbde215254598efdf6ce8
• https://git.kernel.org/stable/c/f5fec1588642e415a3d72e02140160661b303940
• https://git.kernel.org/stable/c/5447f9708d9e4c17a647b16a9cb29e9e02820bd9