diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2018-09-12 23:06:10 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-09-12 23:30:02 +0200 |
| commit | dd066823db2ac4e22f721ec85190817b58059a54 (patch) | |
| tree | f7f40317bb1474a382035fb58a120e73c82fec46 | |
| parent | bpf: btf: Fix end boundary calculation for type section (diff) | |
| download | linux-dd066823db2ac4e22f721ec85190817b58059a54.tar.xz linux-dd066823db2ac4e22f721ec85190817b58059a54.zip | |
bpf/verifier: disallow pointer subtraction
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>
| -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 92246117d2b0..bb07e74b34a2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3163,7 +3163,7 @@ 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; } |