From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, kernel-team@meta.com
Subject: Re: [PATCH bpf-next 04/13] bpf: add register bounds sanity checks and sanitization
Date: Fri, 03 Nov 2023 23:39:07 +0200 [thread overview]
Message-ID: <e8adb5bcc16c1a9744f5bee420111ef06da4dd1c.camel@gmail.com> (raw)
In-Reply-To: <CAEf4Bzbc_uc=77ZkipBQ_00WEh1-3zaUzOWPq4kwk7Q=YNLd6Q@mail.gmail.com>
On Fri, 2023-11-03 at 14:11 -0700, Andrii Nakryiko wrote:
[...]
> > This is a useful check but I'm not sure about placement.
> > It might be useful to guard calls to coerce_subreg_to_size_sx() as well.
>
> Those are covered as part of the ALU/ALU64 check.
Oh, right, sorry.
> My initial idea was to add it into reg_bounds_sync() and make
> reg_bounds_sync() return int (right now it's void). But discussing
> with Alexei we came to the conclusion that it would be a bit too much
> code churn for little gain. This coerce_subreg...() stuff, it's also
> void, so we'd need to propagate errors out of it as well.
>
> In the end I think I'm covering basically all relevant cases (ALU,
> LDX, RETVAL, COND_JUMP).
>
> > Maybe insert it as a part of the main do_check() loop but filter
> > by instruction class (and also force on stack_pop)?
>
> That would be a) a bit wasteful, and b) I'd need to re-interpret BPF_X
> vs BPF_K and all the other idiosyncrasies of instruction encoding. So
> it doesn't seem like a good idea.
tbh I think that compartmentalizing this check worth a little bit of
churn, but ok, not that important.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
next prev parent reply other threads:[~2023-11-03 21:39 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-03 0:08 [PATCH bpf-next 00/13] BPF register bounds range vs range support Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 01/13] bpf: generalize reg_set_min_max() to handle non-const register comparisons Andrii Nakryiko
2023-11-03 7:52 ` Shung-Hsi Yu
2023-11-03 8:33 ` Shung-Hsi Yu
2023-11-03 20:39 ` Andrii Nakryiko
2023-11-03 20:48 ` Andrii Nakryiko
2023-11-06 2:22 ` Shung-Hsi Yu
2023-11-03 16:20 ` Eduard Zingerman
2023-11-03 20:39 ` Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 02/13] bpf: generalize is_scalar_branch_taken() logic Andrii Nakryiko
2023-11-03 0:13 ` Andrii Nakryiko
2023-11-03 16:47 ` Eduard Zingerman
2023-11-03 20:59 ` Andrii Nakryiko
2023-11-03 21:02 ` Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 03/13] bpf: enhance BPF_JEQ/BPF_JNE is_branch_taken logic Andrii Nakryiko
2023-11-03 17:28 ` Eduard Zingerman
2023-11-09 8:39 ` Shung-Hsi Yu
2023-11-03 0:08 ` [PATCH bpf-next 04/13] bpf: add register bounds sanity checks and sanitization Andrii Nakryiko
2023-11-03 2:13 ` Andrii Nakryiko
2023-11-03 17:56 ` Eduard Zingerman
2023-11-03 21:11 ` Andrii Nakryiko
2023-11-03 21:39 ` Eduard Zingerman [this message]
2023-11-09 8:30 ` Shung-Hsi Yu
2023-11-03 0:08 ` [PATCH bpf-next 05/13] bpf: remove redundant s{32,64} -> u{32,64} deduction logic Andrii Nakryiko
2023-11-03 22:16 ` Eduard Zingerman
2023-11-09 8:43 ` Shung-Hsi Yu
2023-11-03 0:08 ` [PATCH bpf-next 06/13] bpf: make __reg{32,64}_deduce_bounds logic more robust Andrii Nakryiko
2023-11-03 22:27 ` Eduard Zingerman
2023-11-09 9:02 ` Shung-Hsi Yu
2023-11-03 0:08 ` [PATCH bpf-next 07/13] selftests/bpf: BPF register range bounds tester Andrii Nakryiko
2023-11-03 19:19 ` Alexei Starovoitov
2023-11-03 21:12 ` Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 08/13] selftests/bpf: adjust OP_EQ/OP_NE handling to use subranges for branch taken Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 09/13] selftests/bpf: add range x range test to reg_bounds Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 10/13] selftests/bpf: add randomized reg_bounds tests Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 11/13] selftests/bpf: set BPF_F_TEST_SANITY_SCRIPT by default Andrii Nakryiko
2023-11-03 22:35 ` Eduard Zingerman
2023-11-03 0:08 ` [PATCH bpf-next 12/13] veristat: add ability to set BPF_F_TEST_SANITY_STRICT flag with -r flag Andrii Nakryiko
2023-11-03 0:08 ` [PATCH bpf-next 13/13] selftests/bpf: add iter test requiring range x range logic Andrii Nakryiko
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