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| author | Alexei Starovoitov <ast@kernel.org> | 2018-09-12 14:06:10 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-09-12 23:30:02 +0200 |
| commit | dd066823db2ac4e22f721ec85190817b58059a54 (patch) | |
| tree | f7f40317bb1474a382035fb58a120e73c82fec46 /kernel | |
| parent | 4b1c5d917d34f705096bb7dd8a2bd19b0881970e (diff) | |
| download | linux-0-day-dd066823db2ac4e22f721ec85190817b58059a54.tar.gz linux-0-day-dd066823db2ac4e22f721ec85190817b58059a54.tar.xz | |
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>
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 92246117d2b03..bb07e74b34a22 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; } |