Hi Daniel,
On Mon, Dec 12, 2016 at 6:08 PM, Linux Kernel Mailing List
<linux-kernel@vger.kernel.org> wrote:
> Web:
> https://git.kernel.org/torvalds/c/7bd509e311f408f7a5132fcdde2069af65fa05ae
> Commit: 7bd509e311f408f7a5132fcdde2069af65fa05ae
> Parent: 8d829bdb97dc3a0c9c8090b9b168ca46ea99c8d8
> Refname: refs/heads/master
> Author: Daniel Borkmann <dan...@iogearbox.net>
> AuthorDate: Sun Dec 4 23:19:41 2016 +0100
> Committer: David S. Miller <da...@davemloft.net>
> CommitDate: Mon Dec 5 15:33:11 2016 -0500
>
> bpf: add prog_digest and expose it via fdinfo/netlink
>
> When loading a BPF program via bpf(2), calculate the digest over
> the program's instruction stream and store it in struct bpf_prog's
> digest member. This is done at a point in time before any instructions
> are rewritten by the verifier. Any unstable map file descriptor
> number part of the imm field will be zeroed for the hash.
>
> fdinfo example output for progs:
>
> # cat /proc/1590/fdinfo/5
> pos: 0
> flags: 02000002
> mnt_id: 11
> prog_type: 1
> prog_jited: 1
> prog_digest: b27e8b06da22707513aa97363dfb11c7c3675d28
> memlock: 4096
>
> When programs are pinned and retrieved by an ELF loader, the loader
> can check the program's digest through fdinfo and compare it against
> one that was generated over the ELF file's program section to see
> if the program needs to be reloaded. Furthermore, this can also be
> exposed through other means such as netlink in case of a tc cls/act
> dump (or xdp in future), but also through tracepoints or other
> facilities to identify the program. Other than that, the digest can
> also serve as a base name for the work in progress kallsyms support
> of programs. The digest doesn't depend/select the crypto layer, since
> we need to keep dependencies to a minimum. iproute2 will get support
> for this facility.
>
> Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
> Acked-by: Alexei Starovoitov <a...@kernel.org>
> Signed-off-by: David S. Miller <da...@davemloft.net>
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -136,6 +136,71 @@ void __bpf_prog_free(struct bpf_prog *fp)
> vfree(fp);
> }
>
> +#define SHA_BPF_RAW_SIZE \
> + round_up(MAX_BPF_SIZE + sizeof(__be64) + 1, SHA_MESSAGE_BYTES)
> +
> +/* Called under verifier mutex. */
> +void bpf_prog_calc_digest(struct bpf_prog *fp)
> +{
> + const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
> + static u32 ws[SHA_WORKSPACE_WORDS];
> + static u8 raw[SHA_BPF_RAW_SIZE];
function old new delta
raw - 32832 +32832
Congratulations!
We've found the first nominee for the v4.10-rc1 bloat-o-meter contest! :-(
Can this please be allocated dynamically? Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
