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  1. Dec 14, 2019
  3. Dec 13, 2019
  5. Dec 12, 2019
    • Daniel Borkmann's avatar
      bpf, x86, arm64: Enable jit by default when not built as always-on · 81c22041
      Daniel Borkmann authored 
      After Spectre 2 fix via 290af866 ("bpf: introduce BPF_JIT_ALWAYS_ON
config") most major distros use BPF_JIT_ALWAYS_ON configuration these days
which compiles out the BPF interpreter entirely and always enables the
JIT. Also given recent fix in e1608f3f

 ("bpf: Avoid setting bpf insns
pages read-only when prog is jited"), we additionally avoid fragmenting
the direct map for the BPF insns pages sitting in the general data heap
since they are not used during execution. Latter is only needed when run
through the interpreter.

Since both x86 and arm64 JITs have seen a lot of exposure over the years,
are generally most up to date and maintained, there is more downside in
!BPF_JIT_ALWAYS_ON configurations to have the interpreter enabled by default
rather than the JIT. Add a ARCH_WANT_DEFAULT_BPF_JIT config which archs can
use to set the bpf_jit_{enable,kallsyms} to 1. Back in the days the
bpf_jit_kallsyms knob was set to 0 by default since major distros still
had /proc/kallsyms addresses exposed to unprivileged user space which is
not the case anymore. Hence both knobs are set via BPF_JIT_DEFAULT_ON which
is set to 'y' in case of BPF_JIT_ALWAYS_ON or ARCH_WANT_DEFAULT_BPF_JIT.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/f78ad24795c2966efcc2ee19025fa3459f622185.1575903816.git.daniel@iogearbox.net
      81c22041
    • Daniel Borkmann's avatar
      bpf: Emit audit messages upon successful prog load and unload · bae141f5
      Daniel Borkmann authored 
      

Allow for audit messages to be emitted upon BPF program load and
unload for having a timeline of events. The load itself is in
syscall context, so additional info about the process initiating
the BPF prog creation can be logged and later directly correlated
to the unload event.

The only info really needed from BPF side is the globally unique
prog ID where then audit user space tooling can query / dump all
info needed about the specific BPF program right upon load event
and enrich the record, thus these changes needed here can be kept
small and non-intrusive to the core.

Raw example output:

  # auditctl -D
  # auditctl -a always,exit -F arch=x86_64 -S bpf
  # ausearch --start recent -m 1334
  ...
  ----
  time->Wed Nov 27 16:04:13 2019
  type=PROCTITLE msg=audit(1574867053.120:84664): proctitle="./bpf"
  type=SYSCALL msg=audit(1574867053.120:84664): arch=c000003e syscall=321   \
    success=yes exit=3 a0=5 a1=7ffea484fbe0 a2=70 a3=0 items=0 ppid=7477    \
    pid=12698 auid=1001 uid=1001 gid=1001 euid=1001 suid=1001 fsuid=1001    \
    egid=1001 sgid=1001 fsgid=1001 tty=pts2 ses=4 comm="bpf"                \
    exe="/home/jolsa/auditd/audit-testsuite/tests/bpf/bpf"                  \
    subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
  type=UNKNOWN[1334] msg=audit(1574867053.120:84664): prog-id=76 op=LOAD
  ----
  time->Wed Nov 27 16:04:13 2019
  type=UNKNOWN[1334] msg=audit(1574867053.120:84665): prog-id=76 op=UNLOAD
  ...

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Co-developed-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Acked-by: default avatarPaul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/bpf/20191206214934.11319-1-jolsa@kernel.org
      bae141f5
  7. Dec 11, 2019
  9. Dec 10, 2019