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From: Peilin Ye <yepeilin@google.com>
To: Eduard Zingerman <eddyz87@gmail.com>
Cc: bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	bpf@ietf.org, Xu Kuohai <xukuohai@huaweicloud.com>,
	David Vernet <void@manifault.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Puranjay Mohan <puranjay@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Quentin Monnet <qmo@kernel.org>,
	Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>,
	Josh Don <joshdon@google.com>, Barret Rhoden <brho@google.com>,
	Neel Natu <neelnatu@google.com>,
	Benjamin Segall <bsegall@google.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next v1 3/8] bpf: Introduce load-acquire and store-release instructions
Date: Wed, 29 Jan 2025 22:17:54 +0000	[thread overview]
Message-ID: <Z5qpEkXq-X6ci9UU@google.com> (raw)
In-Reply-To: <f5b72fa9460e4eda6e6b36756db855bfec67744a.camel@gmail.com>

On Tue, Jan 28, 2025 at 05:30:19PM -0800, Eduard Zingerman wrote:
> On Sat, 2025-01-25 at 02:18 +0000, Peilin Ye wrote:
> > +static int check_atomic_store(struct bpf_verifier_env *env, int insn_idx,
> > +			      struct bpf_insn *insn)
> > +{
> > +	int err;
> > +
> > +	err = check_reg_arg(env, insn->src_reg, SRC_OP);
> > +	if (err)
> > +		return err;
> > +
> > +	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
> > +	if (err)
> > +		return err;
> > +
> > +	if (is_pointer_value(env, insn->src_reg)) {
> > +		verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
> > +		return -EACCES;
> > +	}
> 
> Nit: this check is done by check_mem_access(), albeit only for
>      PTR_TO_MEM, I think it's better to be consistent with
>      what happens for regular stores and avoid this check here.

Got it.  Unprivileged programs will be able to store-release pointers to
the stack, then.  I'll update selftests accordingly.

Thanks,
Peilin Ye



  reply	other threads:[~2025-01-29 22:19 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-25  2:16 [PATCH bpf-next v1 0/8] Introduce load-acquire and store-release BPF instructions Peilin Ye
2025-01-25  2:17 ` [PATCH bpf-next v1 1/8] bpf/verifier: Factor out atomic_ptr_type_ok() Peilin Ye
2025-01-25  2:18 ` [PATCH bpf-next v1 2/8] bpf/verifier: Factor out check_atomic_rmw() Peilin Ye
2025-01-25  2:18 ` [PATCH bpf-next v1 3/8] bpf: Introduce load-acquire and store-release instructions Peilin Ye
2025-01-29  0:19   ` Eduard Zingerman
2025-01-29 22:04     ` Peilin Ye
2025-01-29 22:42       ` Eduard Zingerman
2025-01-30  3:10         ` Peilin Ye
2025-01-29  1:30   ` Eduard Zingerman
2025-01-29 22:17     ` Peilin Ye [this message]
2025-01-30  0:41   ` Alexei Starovoitov
2025-01-30  3:38     ` Peilin Ye
2025-01-25  2:18 ` [PATCH bpf-next v1 4/8] arm64: insn: Add BIT(23) to {load,store}_ex's mask Peilin Ye
2025-01-25  2:19 ` [PATCH bpf-next v1 5/8] arm64: insn: Add load-acquire and store-release instructions Peilin Ye
2025-01-25  2:19 ` [PATCH bpf-next v1 6/8] bpf, arm64: Support " Peilin Ye
2025-01-25  2:19 ` [PATCH bpf-next v1 7/8] selftests/bpf: Add selftests for " Peilin Ye
2025-01-29  1:06   ` Eduard Zingerman
2025-01-29  2:07     ` Ihor Solodrai
2025-01-29  2:17       ` Eduard Zingerman
2025-01-30  0:03     ` Peilin Ye
2025-02-04  0:30     ` Peilin Ye
2025-02-04  0:52       ` Eduard Zingerman
2025-02-04  1:29         ` Peilin Ye
2025-01-25  2:19 ` [PATCH bpf-next v1 8/8] bpf, docs: Update instruction-set.rst " Peilin Ye
2025-01-30  0:44   ` Alexei Starovoitov
2025-01-30  7:33     ` Peilin Ye

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