From: Gao Xiang <hsiangkao@linux.alibaba.com>
To: Junrui Luo <moonafterrain@outlook.com>
Cc: Gao Xiang <xiang@kernel.org>, Chao Yu <chao@kernel.org>,
Yue Hu <zbestahu@gmail.com>,
Jeffle Xu <jefflexu@linux.alibaba.com>,
Sandeep Dhavale <dhavale@google.com>,
Hongbo Li <lihongbo22@huawei.com>,
Chunhai Guo <guochunhai@vivo.com>,
"linux-erofs@lists.ozlabs.org" <linux-erofs@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Yuhao Jiang <danisjiang@gmail.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()
Date: Thu, 9 Apr 2026 20:14:46 +0800 [thread overview]
Message-ID: <17f2ec58-e8ec-4f59-9e8f-0e88bde7d98b@linux.alibaba.com> (raw)
In-Reply-To: <1922A494-0E56-4E11-9D3E-3604BCBE33AD@outlook.com>
On 2026/4/9 19:49, Junrui Luo wrote:
> On Thu, Apr 09, 2026 at 06:56:42PM +0800, Gao Xiang wrote:
>> Can you share your initial crafted image binary
>> with `gzip -9 | base64` encoding here?
>
> $ gzip -9 < /tmp/erofs-test/test.erofs | base64
> H4sIAJGR12kCA+3SPUoDQRgG4MkmkkZk8QRbRFIIi9hbpEjrHQI5ghfwCN5BLCzTGtLbBI+gdilS
> Jo1CnIm7GEXFxhT6PDDwfrs73/ywIQD/1ePD4r7Ou6ETsrq4mu7XcWfj++Pb58nJU/9iPNtbjhan
> 04/9GtX4qVYc814WDqt6FaX5s+ZwXXeq52lndT6IuVvlblytLMvh4Gzwaf90nsvz2DF/21+20T/l
> dgp5s1jXRaN4t/8izsy/OUB6e/Qa79r+JwAAAAAAAL52vQVuGQAAAP6+my1wywAAAAAAAADwu14A
> TsEYtgBQAAA=
>
> In QEMU:
> $ mount -t erofs -o cache_strategy=disabled test.erofs /mnt
> $ dd if=/mnt/data of=/dev/null bs=4096 count=1
>
>> I think the proper place to fix this is in
>> z_erofs_map_sanity_check().
>
> I will resend with the check in
> z_erofs_map_sanity_check() instead if the reproducer is acceptable.
It's not a very trivial fix without having some more
understanding of EROFS compression codebase, I will
add your `Repored-by:` and try to tidy up the related
code.
Thanks,
Gao Xiang
>
> Thanks,
> Junrui Luo
next prev parent reply other threads:[~2026-04-09 12:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-09 6:57 [PATCH] erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap() Junrui Luo
2026-04-09 7:28 ` Gao Xiang
2026-04-09 10:38 ` Junrui Luo
2026-04-09 10:56 ` Gao Xiang
2026-04-09 11:49 ` Junrui Luo
2026-04-09 12:14 ` Gao Xiang [this message]
2026-04-09 13:22 ` Gao Xiang
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