Daniel Borkmann
6d59b7dbf7
The assumption of unconditionally reloading skb pointers on
BPF helper calls where bpf_helper_changes_pkt_data() holds
true is wrong. There can be different contexts where the
BPF helper would enforce a reload such as in case of XDP.
Here, we do have a struct xdp_buff instead of struct sk_buff
as context, thus this will access garbage.
JITs only ever need to deal with cached skb pointer reload
when ld_abs/ind was seen, therefore guard the reload behind
SEEN_SKB only. Tested on s390x.
Fixes: 9db7f2b818 ("s390/bpf: recache skb->data/hlen for skb_vlan_push/pop")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.