Commit dd066823 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann

bpf/verifier: disallow pointer subtraction

Subtraction of pointers was accidentally allowed for unpriv programs
by commit 82abbf8d. Revert that part of commit.

Fixes: 82abbf8d ("bpf: do not allow root to mangle valid pointers")
Reported-by: 's avatarJann Horn <jannh@google.com>
Acked-by: 's avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: 's avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: 's avatarDaniel Borkmann <daniel@iogearbox.net>
parent 4b1c5d91
......@@ -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;
}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment