diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2018-09-12 14:06:10 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-29 02:55:57 -0700 |
| commit | bc35488686c34703e5f0909c7a6cb0b942bfcf58 (patch) | |
| tree | fdb0224dd72216e0a000a0bcf9c85041c3d8208a /kernel | |
| parent | 909828a2920bb029f847c8d96385cba941e9790d (diff) | |
bpf/verifier: disallow pointer subtraction
commit dd066823db2ac4e22f721ec85190817b58059a54 upstream.
Subtraction of pointers was accidentally allowed for unpriv programs
by commit 82abbf8d2fc4. Revert that part of commit.
Fixes: 82abbf8d2fc4 ("bpf: do not allow root to mangle valid pointers")
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 63aaac52a265..adbe21c8876e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3132,7 +3132,7 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, * an arbitrary scalar. Disallow all math except * pointer subtraction */ - if (opcode == BPF_SUB){ + if (opcode == BPF_SUB && env->allow_ptr_leaks) { mark_reg_unknown(env, regs, insn->dst_reg); return 0; } |