[PATCH] kconfig: Avoid format overflow warning from GCC 8.1

[PATCH] kconfig: Avoid format overflow warning from GCC 8.1

[Nathan Chancellor]

In file included from scripts/kconfig/zconf.tab.c:2485:
scripts/kconfig/confdata.c: In function ‘conf_write’:
scripts/kconfig/confdata.c:773:22: warning: ‘%s’ directive writing likely 7 or more bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
  sprintf(newname, "%s%s", dirname, basename);
                      ^~
scripts/kconfig/confdata.c:773:19: note: assuming directive output of 7 bytes
  sprintf(newname, "%s%s", dirname, basename);
                   ^~~~~~
scripts/kconfig/confdata.c:773:2: note: ‘sprintf’ output 1 or more bytes (assuming 4104) into a destination of size 4097
  sprintf(newname, "%s%s", dirname, basename);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
scripts/kconfig/confdata.c:776:23: warning: ‘.tmpconfig.’ directive writing 11 bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
   sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
                       ^~~~~~~~~~~
scripts/kconfig/confdata.c:776:3: note: ‘sprintf’ output between 13 and 4119 bytes into a destination of size 4097
   sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Increase the size of tmpname and newname to make GCC happy.

Cc: stable@vger.kernel.org
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 scripts/kconfig/confdata.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 5f87ad561b08..39e20974f4a3 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -720,7 +720,7 @@ int conf_write(const char *name)
 	struct menu *menu;
 	const char *basename;
 	const char *str;
-	char dirname[PATH_MAX+1], tmpname[PATH_MAX+1], newname[PATH_MAX+1];
+	char dirname[PATH_MAX+1], tmpname[PATH_MAX+22], newname[PATH_MAX+8];
 	char *env;
 
 	dirname[0] = 0;
-- 
2.17.1

Re: [PATCH] kconfig: Avoid format overflow warning from GCC 8.1

[Masahiro Yamada]

2018-06-03 1:02 GMT+09:00 Nathan Chancellor <natechancellor@gmail.com>:
> In file included from scripts/kconfig/zconf.tab.c:2485:
> scripts/kconfig/confdata.c: In function ‘conf_write’:
> scripts/kconfig/confdata.c:773:22: warning: ‘%s’ directive writing likely 7 or more bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
>   sprintf(newname, "%s%s", dirname, basename);
>                       ^~
> scripts/kconfig/confdata.c:773:19: note: assuming directive output of 7 bytes
>   sprintf(newname, "%s%s", dirname, basename);
>                    ^~~~~~
> scripts/kconfig/confdata.c:773:2: note: ‘sprintf’ output 1 or more bytes (assuming 4104) into a destination of size 4097
>   sprintf(newname, "%s%s", dirname, basename);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> scripts/kconfig/confdata.c:776:23: warning: ‘.tmpconfig.’ directive writing 11 bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
>    sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
>                        ^~~~~~~~~~~
> scripts/kconfig/confdata.c:776:3: note: ‘sprintf’ output between 13 and 4119 bytes into a destination of size 4097
>    sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Increase the size of tmpname and newname to make GCC happy.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---

Applied to linux-kbuild.  Thanks!


>  scripts/kconfig/confdata.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
> index 5f87ad561b08..39e20974f4a3 100644
> --- a/scripts/kconfig/confdata.c
> +++ b/scripts/kconfig/confdata.c
> @@ -720,7 +720,7 @@ int conf_write(const char *name)
>         struct menu *menu;
>         const char *basename;
>         const char *str;
> -       char dirname[PATH_MAX+1], tmpname[PATH_MAX+1], newname[PATH_MAX+1];
> +       char dirname[PATH_MAX+1], tmpname[PATH_MAX+22], newname[PATH_MAX+8];
>         char *env;
>
>         dirname[0] = 0;
> --
> 2.17.1
>
> --
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-- 
Best Regards
Masahiro Yamada