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From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: <bot+bpf-ci@kernel.org>, <bpf@vger.kernel.org>
Cc: <daniel@iogearbox.net>, <andrii@kernel.org>, <eddyz87@gmail.com>,
	<memxor@gmail.com>, <martin.lau@kernel.org>,
	<yonghong.song@linux.dev>, <mason@kernel.org>,
	<ihor.solodrai@linux.dev>
Subject: Re: [PATCH bpf-next v3 06/14] libbpf: Relocate pointers that are stored in arena
Date: Wed, 04 Nov 2026 02:30:37 +0000	[thread overview]
Message-ID: <DMM2NHPR2UJS.P9V6P9HRJFK6@gmail.com> (raw)
In-Reply-To: <f4144b15c814d1c4ed9be5e4e4f4f8f5746bb7638ad8234210e5dd2524b1e151@mail.kernel.org>

On Tue, Nov 03, 2026 at 05:59 PM bot+bpf-ci@kernel.org <bot+bpf-ci@kernel.org> wrote:
>> +		ptrs->off = rel->r_offset;
>> +		ptrs->targ_off = sym->st_value;
>
> Can rel->r_offset point past the end of the arena data here?  It is stored
> in ptrs->off without being compared against the size of the .addr_space.1
> data.

[...]

> Should this function do a similar check and return -LIBBPF_ERRNO__FORMAT?

Not a bug. Only a hand-made ELF has such r_offset.
The input of libbpf is trusted.
I thought bpf CI knows this better than sashiko :(

> relocate_arena_ptrs() would then read past the heap allocation and use
> garbage off values as write targets.  Should a second call be rejected when
> obj->arena_ptrs is already set?

No. See my reply to sashiko.

  reply	other threads:[~2026-11-04  2:30 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-04  1:23 [PATCH bpf-next v3 00/14] bpf: A stack in arena Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 01/14] libbpf: Make arena 4 Gbyte when max_entries is not set Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 02/14] selftests/bpf: Test the default size of arena Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 03/14] bpf: Treat addr_space_cast of a pointer that is not in arena as a move Alexei Starovoitov
2026-11-04  2:12   ` bot+bpf-ci
2026-11-04  2:32     ` Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 04/14] selftests/bpf: Test addr_space_cast of pointers that are not in arena Alexei Starovoitov
2026-11-04  1:40   ` sashiko-bot
2026-11-04  1:23 ` [PATCH bpf-next v3 05/14] libbpf: Support .bss.addr_space.1 section Alexei Starovoitov
2026-11-04  1:59   ` bot+bpf-ci
2026-11-04  1:23 ` [PATCH bpf-next v3 06/14] libbpf: Relocate pointers that are stored in arena Alexei Starovoitov
2026-11-04  1:44   ` sashiko-bot
2026-11-04  2:02     ` Alexei Starovoitov
2026-11-04  2:32       ` Roman Gushchin
2026-11-04  2:37         ` Alexei Starovoitov
2026-11-04  1:59   ` bot+bpf-ci
2026-11-04  2:30     ` Alexei Starovoitov [this message]
2026-11-04  1:23 ` [PATCH bpf-next v3 07/14] selftests/bpf: Test pointers in arena and .bss.addr_space.1 Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 08/14] bpf: Introduce bpf register BPF_REG_ARENA_SP Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 09/14] bpf: Add stacks for programs to arena Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 10/14] bpf, x86: Add BPF_ATOMIC_LOCAL Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 11/14] bpf: Support BPF_REG_ARENA_SP in the verifier Alexei Starovoitov
2026-11-04  2:12   ` bot+bpf-ci
2026-11-04  1:23 ` [PATCH bpf-next v3 12/14] bpf, x86: Support BPF_REG_ARENA_SP Alexei Starovoitov
2026-11-04  1:23 ` [PATCH bpf-next v3 13/14] bpf, arm64: " Alexei Starovoitov
2026-11-04  1:24 ` [PATCH bpf-next v3 14/14] selftests/bpf: Add tests for BPF_REG_ARENA_SP Alexei Starovoitov
2026-11-04  2:12   ` bot+bpf-ci
2026-11-04  2:29     ` Alexei Starovoitov
2026-11-04  3:31 ` [PATCH bpf-next v3 00/14] bpf: A stack in arena Alexei Starovoitov
2026-11-04  7:35   ` Kumar Kartikeya Dwivedi
2026-11-04 18:02     ` Alexei Starovoitov
2026-11-04 20:10 ` patchwork-bot+netdevbpf

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