From: Anders Larsen <al@alarsen.net>
To: Tong Zhang <ztong0001@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] qnx4_match: do not over run the buffer
Date: Sat, 21 Nov 2020 22:40:17 +0100 [thread overview]
Message-ID: <2474566.rpppqFFLNx@alarsen.net> (raw)
In-Reply-To: <20201120212120.2502522-1-ztong0001@gmail.com>
On Friday, 2020-11-20 22:21 Tong Zhang wrote:
> the di_fname may not terminated by '\0', use strnlen to prevent buffer
> overrun
>
> ---
> fs/qnx4/namei.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c
> index 8d72221735d7..c0e79094f578 100644
> --- a/fs/qnx4/namei.c
> +++ b/fs/qnx4/namei.c
> @@ -40,7 +40,7 @@ static int qnx4_match(int len, const char *name,
> } else {
> namelen = QNX4_SHORT_NAME_MAX;
> }
> - thislen = strlen( de->di_fname );
> + thislen = strnlen( de->di_fname, QNX4_SHORT_NAME_MAX );
that should be
+ thislen = strnlen( de->di_fname, namelen );
otherwise the length of a filename would always be limited to QNX4_SHORT_NAME_MAX (16) characters.
> if ( thislen > namelen )
> thislen = namelen;
These two lines can be dropped now, as the result of strnlen() cannot exceed namelen anyway.
Cheers
Anders
next prev parent reply other threads:[~2020-11-21 21:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 21:21 [PATCH v1] qnx4_match: do not over run the buffer Tong Zhang
2020-11-21 21:40 ` Anders Larsen [this message]
2020-11-21 21:47 ` Tong Zhang
2020-11-21 21:57 ` Anders Larsen
2020-11-22 1:27 ` Tong Zhang
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