linux-kernel - Re: [PATCH] nfsroot: Fix missing check for return value of strsep()

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Message-ID: <83fd43a8acec2d07ee7bd49afc830988354784ed.camel@hammerspace.com>
Date:   Wed, 14 Jun 2023 15:19:59 +0000
From:   Trond Myklebust <trondmy@...merspace.com>
To:     "cymi20@...an.edu.cn" <cymi20@...an.edu.cn>
CC:     "anna@...nel.org" <anna@...nel.org>,
        "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] nfsroot: Fix missing check for return value of strsep()

On Wed, 2023-06-14 at 07:30 -0700, Chenyuan Mi wrote:
> [You don't often get email from cymi20@...an.edu.cn. Learn why this
> is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> The strsep() function in root_nfs_parse_options() may return NULL
> if argument 'incoming' is NULL. Since 'incoming' has Null check in
> this function, it is also need to add Null check for return value
>  of strsep().
> 
> Found by our static analysis tool.
> 
> Signed-off-by: Chenyuan Mi <cymi20@...an.edu.cn>
> ---
>  fs/nfs/nfsroot.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
> index 620329b7e6ae..55c594dede9f 100644
> --- a/fs/nfs/nfsroot.c
> +++ b/fs/nfs/nfsroot.c
> @@ -198,7 +198,7 @@ static int __init root_nfs_parse_options(char
> *incoming, char *exppath,
>          * Set the NFS remote path
>          */
>         p = strsep(&incoming, ",");
> -       if (*p != '\0' && strcmp(p, "default") != 0)
> +       if (p != NULL && *p != '\0' && strcmp(p, "default") != 0)
>                 if (root_nfs_copy(exppath, p, exppathlen))
>                         return -1;
> 

Huh? root_nfs_parse_options() is called from exactly two callsites, and
in both cases 'incoming' is guaranteed to be non-NULL.

NACKed
-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@...merspace.com