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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Nathan Chancellor" <natechancellor@gmail.com>,
        "Masahiro Yamada" <yamada.masahiro@socionext.com>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.899768807@decadent.org.uk>
Subject: [PATCH 3.16 115/366] kconfig: Avoid format overflow warning from
 GCC 8.1
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nathan Chancellor <natechancellor@gmail.com>

commit 2ae89c7a82ea9d81a19b4fc2df23bef4b112f24e upstream.

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.

Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 scripts/kconfig/confdata.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -738,7 +738,7 @@ 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;