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

Andrey Zhizhikin
2019-12-17T21:21:46Z

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@gmail.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@leica-geosystems.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@kernel.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.