netdev - Re: [PATCH] tools lib api fs: fix gcc9 compilation error

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Date:   Tue, 17 Dec 2019 22:21:30 +0100
From:   Andrey Zhizhikin <andrey.z@...il.com>
To:     ast@...nel.org, daniel@...earbox.net, kafai@...com,
        songliubraving@...com, yhs@...com, andriin@...com,
        sergey.senozhatsky@...il.com, pmladek@...e.com,
        wangkefeng.wang@...wei.com, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org
Cc:     Andrey Zhizhikin <andrey.zhizhikin@...ca-geosystems.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Jiri Olsa <jolsa@...nel.org>
Subject: Re: [PATCH] tools lib api fs: fix gcc9 compilation error

Hello all,

I'd like to have a gentle ping on this patch, if someone could review
and apply it - I'd really appreciate it.

On Wed, Dec 11, 2019 at 9:01 AM Andrey Zhizhikin <andrey.z@...il.com> wrote:
>
> GCC9 introduced string hardening mechanisms, which exhibits the error
> during fs api compilation:
>
> error: '__builtin_strncpy' specified bound 4096 equals destination size
> [-Werror=stringop-truncation]
>
> This comes when the length of copy passed to strncpy is is equal to
> destination size, which could potentially lead to buffer overflow.
>
> There is a need to mitigate this potential issue by limiting the size of
> destination by 1 and explicitly terminate the destination with NULL.
>
> Signed-off-by: Andrey Zhizhikin <andrey.zhizhikin@...ca-geosystems.com>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/lib/api/fs/fs.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
> index 11b3885e833e..027b18f7ed8c 100644
> --- a/tools/lib/api/fs/fs.c
> +++ b/tools/lib/api/fs/fs.c
> @@ -210,6 +210,7 @@ static bool fs__env_override(struct fs *fs)
>         size_t name_len = strlen(fs->name);
>         /* name + "_PATH" + '\0' */
>         char upper_name[name_len + 5 + 1];
> +
>         memcpy(upper_name, fs->name, name_len);
>         mem_toupper(upper_name, name_len);
>         strcpy(&upper_name[name_len], "_PATH");
> @@ -219,7 +220,8 @@ static bool fs__env_override(struct fs *fs)
>                 return false;
>
>         fs->found = true;
> -       strncpy(fs->path, override_path, sizeof(fs->path));
> +       strncpy(fs->path, override_path, sizeof(fs->path) - 1);
> +       fs->path[sizeof(fs->path) - 1] = '\0';
>         return true;
>  }
>
> --
> 2.17.1
>


-- 
Regards,
Andrey.