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From: ChenXiaoSong <chenxiaosong@chenxiaosong.com>
To: Steve French <sfrench@samba.org>
Cc: linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paulo Alcantara <pc@manguebit.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ronnie Sahlberg <ronniesahlberg@gmail.com>,
	Shyam Prasad N <sprasad@microsoft.com>,
	Tom Talpey <tom@talpey.com>, Bharath SM <bharathsm@microsoft.com>,
	samba-technical@lists.samba.org, stable <stable@kernel.org>
Subject: Re: [PATCH 1/2] smb: client: fix off-by-8 bounds check in check_wsl_eas()
Date: Thu, 9 Apr 2026 11:09:47 +0800	[thread overview]
Message-ID: <77013349-ff89-4593-985d-520d967d2638@chenxiaosong.com> (raw)
In-Reply-To: <2026040822-shortly-chump-8518@gregkh>

Hi Steve,

Should we use `get_unaligned_le32()` to get unaligned data?

> static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
>                                    void *ptr)                   
> {                                                               
>         u32 uid = le32_to_cpu(*(__le32 *)ptr);
>         ...
> }                                                               


> 
> Additionally, does parsing these extended attributes cause unaligned memory
> accesses?
> When parsing WSL extended attributes, the code derives the value pointer
> at an offset of ea_name_length (which is 6) plus 1 from ea_data. Since
> ea is a 4-byte aligned structure, the value sits at an unaligned offset.
> Helper functions like wsl_make_kuid() explicitly cast this unaligned
> pointer to a 32-bit type and dereference it:
>     le32_to_cpu(*(__le32 *)v);
>     
> Could this trigger an unaligned access exception and crash the kernel on
> architectures with strict alignment requirements?

-- 
ChenXiaoSong <chenxiaosong@kylinos.cn>
Chinese Homepage: chenxiaosong.com
English Homepage: chenxiaosong.com/en


  parent reply	other threads:[~2026-04-09  3:11 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-06 13:49 [PATCH 0/2] smb: some potential bugfixes Greg Kroah-Hartman
2026-04-06 13:49 ` [PATCH 1/2] smb: client: fix off-by-8 bounds check in check_wsl_eas() Greg Kroah-Hartman
2026-04-08  2:51   ` ChenXiaoSong
2026-04-08  5:39     ` Greg Kroah-Hartman
2026-04-08  5:58       ` ChenXiaoSong
2026-04-08  6:15         ` Greg Kroah-Hartman
2026-04-08  6:19           ` ChenXiaoSong
2026-04-08  6:40             ` Greg Kroah-Hartman
2026-04-08  6:52               ` ChenXiaoSong
2026-04-08  6:56                 ` Greg Kroah-Hartman
2026-04-09  3:09       ` ChenXiaoSong [this message]
2026-04-08  9:39   ` Yuanfu Xie
2026-04-06 13:49 ` [PATCH 2/2] smb: client: fix OOB reads parsing symlink error response Greg Kroah-Hartman
2026-04-08  9:01   ` ChenXiaoSong
2026-04-07  3:03 ` [PATCH 0/2] smb: some potential bugfixes Paulo Alcantara
     [not found]   ` <CAH2r5mvXFzWxs70Jmg=yWddmcHs+Bpf8eiBUvyc4oOMLzdCY7w@mail.gmail.com>
2026-04-08  5:45     ` Greg Kroah-Hartman

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