Re: [PATCH v4 1/2] bpf: Skip scalar adjustment for BPF_NEG if dst is a pointer

[Eduard Zingerman]

On Thu, 2025-10-02 at 00:47 +0530, Brahmajit Das wrote:
> In check_alu_op(), the verifier currently calls check_reg_arg() and
> adjust_scalar_min_max_vals() unconditionally for BPF_NEG operations.
> However, if the destination register holds a pointer, these scalar
> adjustments are unnecessary and potentially incorrect.
> 
> This patch adds a check to skip the adjustment logic when the destination
> register contains a pointer.
> 
> Reported-by: syzbot+d36d5ae81e1b0a53ef58@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=d36d5ae81e1b0a53ef58
> Fixes: aced132599b3 ("bpf: Add range tracking for BPF_NEG")
> Suggested-by: KaFai Wan <kafai.wan@xxxxxxxxx>
> Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
> Signed-off-by: Brahmajit Das <listout@xxxxxxxxxxx>
> ---

Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>

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