From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, adobriyan@gmail.com,
shakeel.butt@linux.dev, hannes@cmpxchg.org, osandov@osandov.com,
song@kernel.org, jannh@google.com,
linux-fsdevel@vger.kernel.org, willy@infradead.org,
stable@vger.kernel.org
Subject: Re: [PATCH v4 bpf-next 01/10] lib/buildid: harden build ID parsing logic
Date: Thu, 8 Aug 2024 15:44:44 -0700 [thread overview]
Message-ID: <CAEf4Bzawbs-hTzurU1pNu30=U=2V84_OsW62PiKpFS-2Ayz5KQ@mail.gmail.com> (raw)
In-Reply-To: <ZrVFkWQU5qpP2yUh@tassilo>
On Thu, Aug 8, 2024 at 3:24 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> > + name_sz = READ_ONCE(nhdr->n_namesz);
> > + desc_sz = READ_ONCE(nhdr->n_descsz);
> > + new_offs = note_offs + sizeof(Elf32_Nhdr) + ALIGN(name_sz, 4) + ALIGN(desc_sz, 4);
>
> Don't you need to check the name_sz and desc_sz overflows separately?
>
> Otherwise name_sz could be ~0 and desc_sz small (or reversed) and the check
> below wouldn't trigger, but still bad things could happen.
Yes, both sizes are full u32, so yes, they could technically both
overflow resulting in final non-overflown new_offs. I'll switch the
additions to be done step by step.
>
>
> > + if (new_offs <= note_offs /* overflow */ || new_offs > note_size)
> > + break;
>
> -Andi
prev parent reply other threads:[~2024-08-08 22:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240807234029.456316-1-andrii@kernel.org>
[not found] ` <20240807234029.456316-3-andrii@kernel.org>
2024-08-08 18:33 ` [PATCH v4 bpf-next 02/10] lib/buildid: add single folio-based file reader abstraction Shakeel Butt
[not found] ` <20240807234029.456316-7-andrii@kernel.org>
2024-08-08 18:40 ` [PATCH v4 bpf-next 06/10] lib/buildid: implement sleepable build_id_parse() API Shakeel Butt
2024-08-08 20:15 ` Andrii Nakryiko
2024-08-08 20:57 ` Jann Horn
2024-08-08 21:23 ` Andrii Nakryiko
2024-08-08 21:02 ` Shakeel Butt
2024-08-08 21:21 ` Andrii Nakryiko
[not found] ` <20240807234029.456316-2-andrii@kernel.org>
2024-08-08 22:24 ` [PATCH v4 bpf-next 01/10] lib/buildid: harden build ID parsing logic Andi Kleen
2024-08-08 22:44 ` Andrii Nakryiko [this message]
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