path: root/include/uapi/linux/tc_act/tc_bpf.h
diff options
authorDaniel Borkmann <daniel@iogearbox.net>2017-01-13 23:38:15 +0100
committerDavid S. Miller <davem@davemloft.net>2017-01-16 14:03:31 -0500
commitf1f7714ea51c56b7163fb1a5acf39c6a204dd758 (patch)
tree9e1d9aeda7fe5b358c6d7ed71ccfcdcd576f313a /include/uapi/linux/tc_act/tc_bpf.h
parenttipc: allocate user memory with GFP_KERNEL flag (diff)
bpf: rework prog_digest into prog_tag
Commit 7bd509e311f4 ("bpf: add prog_digest and expose it via fdinfo/netlink") was recently discussed, partially due to admittedly suboptimal name of "prog_digest" in combination with sha1 hash usage, thus inevitably and rightfully concerns about its security in terms of collision resistance were raised with regards to use-cases. The intended use cases are for debugging resp. introspection only for providing a stable "tag" over the instruction sequence that both kernel and user space can calculate independently. It's not usable at all for making a security relevant decision. So collisions where two different instruction sequences generate the same tag can happen, but ideally at a rather low rate. The "tag" will be dumped in hex and is short enough to introspect in tracepoints or kallsyms output along with other data such as stack trace, etc. Thus, this patch performs a rename into prog_tag and truncates the tag to a short output (64 bits) to make it obvious it's not collision-free. Should in future a hash or facility be needed with a security relevant focus, then we can think about requirements, constraints, etc that would fit to that situation. For now, rework the exposed parts for the current use cases as long as nothing has been released yet. Tested on x86_64 and s390x. Fixes: 7bd509e311f4 ("bpf: add prog_digest and expose it via fdinfo/netlink") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi/linux/tc_act/tc_bpf.h')
1 files changed, 1 insertions, 1 deletions
diff --git a/include/uapi/linux/tc_act/tc_bpf.h b/include/uapi/linux/tc_act/tc_bpf.h
index a6b88a6f7f71..975b50dc8d1d 100644
--- a/include/uapi/linux/tc_act/tc_bpf.h
+++ b/include/uapi/linux/tc_act/tc_bpf.h
@@ -27,7 +27,7 @@ enum {