UPSTREAM: bpf: don't let ldimm64 leak map addresses on unprivileged
authorDaniel Borkmann <daniel@iogearbox.net>
Sun, 7 May 2017 22:04:09 +0000 (00:04 +0200)
committerAmit Pundir <amit.pundir@linaro.org>
Mon, 10 Jul 2017 10:57:16 +0000 (16:27 +0530)
commitd76ced0a9c453083ed0211e907e5c7782ed42c43
tree9a78313b256767bd191681cea7907ab5b83a60e9
parentf1b463c65051e905967e38f5bcb15993290ea199
UPSTREAM: bpf: don't let ldimm64 leak map addresses on unprivileged

[ Upstream commit 0d0e57697f162da4aa218b5feafe614fb666db07 ]

The patch fixes two things at once:

1) It checks the env->allow_ptr_leaks and only prints the map address to
   the log if we have the privileges to do so, otherwise it just dumps 0
   as we would when kptr_restrict is enabled on %pK. Given the latter is
   off by default and not every distro sets it, I don't want to rely on
   this, hence the 0 by default for unprivileged.

2) Printing of ldimm64 in the verifier log is currently broken in that
   we don't print the full immediate, but only the 32 bit part of the
   first insn part for ldimm64. Thus, fix this up as well; it's okay to
   access, since we verified all ldimm64 earlier already (including just
   constants) through replace_map_fd_with_map_ptr().

Fixes: 1be7f75d1668 ("bpf: enable non-root eBPF programs")
Fixes: cbd357008604 ("bpf: verifier (add ability to receive verification log)")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 62199770
Change-Id: I62ee47d06ddc669ba2863e8cf24f8f3e7683a461
kernel/bpf/verifier.c