From: David Howells <dhowells@redhat.com>
To: Zijun Hu <zijun_hu@icloud.com>
Cc: dhowells@redhat.com, Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Zijun Hu <quic_zijuhu@quicinc.com>
Subject: Re: [PATCH 1/5] fs/filesystems: Fix potential unsigned integer underflow in fs_name()
Date: Fri, 11 Apr 2025 16:34:05 +0100 [thread overview]
Message-ID: <2425260.1744385645@warthog.procyon.org.uk> (raw)
In-Reply-To: <20250410-fix_fs-v1-1-7c14ccc8ebaa@quicinc.com>
Zijun Hu <zijun_hu@icloud.com> wrote:
> fs_name() has @index as unsigned int, so there is underflow risk for
> operation '@index--'.
>
> Fix by breaking the for loop when '@index == 0' which is also more proper
> than '@index <= 0' for unsigned integer comparison.
There isn't really a risk. The list walked by "tmp" and the checks that this
is or is not NULL will prevent a problem.
I also feel that breaking out of the loop with "<= 0" - even if the variable
is unsigned - is safer, on the off chance that someone in the future changes
the signedness of the variable.
David
next prev parent reply other threads:[~2025-04-11 15:34 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-10 11:45 [PATCH 0/5] fs: bug fixes Zijun Hu
2025-04-10 11:45 ` [PATCH 1/5] fs/filesystems: Fix potential unsigned integer underflow in fs_name() Zijun Hu
2025-04-11 14:34 ` (subset) " Christian Brauner
2025-04-11 14:35 ` Christian Brauner
2025-04-11 14:52 ` Zijun Hu
2025-04-11 15:34 ` David Howells [this message]
2025-04-11 16:06 ` Zijun Hu
2025-04-10 11:45 ` [PATCH 2/5] fs/fs_parse: Fix macro fsparam_u32hex() definition Zijun Hu
2025-04-11 14:17 ` Christian Brauner
2025-04-11 14:25 ` Zijun Hu
2025-04-10 11:45 ` [PATCH 3/5] fs/fs_parse: Fix 3 issues for validate_constant_table() Zijun Hu
2025-04-11 14:37 ` Christian Brauner
2025-04-11 14:48 ` Zijun Hu
2025-04-14 12:39 ` Jan Kara
2025-04-10 11:45 ` [PATCH 4/5] fs/fs_parse: Correct comments of fs_validate_description() Zijun Hu
2025-04-11 14:20 ` (subset) " Christian Brauner
2025-04-10 11:45 ` [PATCH 5/5] fs/fs_context: Mark an unlikely if condition with unlikely() in vfs_parse_monolithic_sep() Zijun Hu
2025-04-11 14:24 ` (subset) " Christian Brauner
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