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From: Arnd Bergmann <arnd@kernel.org>
To: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 05/11] test_hexdump: avoid string truncation warning
Date: Thu, 28 Mar 2024 15:04:49 +0100	[thread overview]
Message-ID: <20240328140512.4148825-6-arnd@kernel.org> (raw)
In-Reply-To: <20240328140512.4148825-1-arnd@kernel.org>

From: Arnd Bergmann <arnd@arndb.de>

gcc can warn when a string is too long to fit into the strncpy()
destination buffer, as it is here depending on the function
arguments:

    inlined from 'test_hexdump_prepare_test.constprop' at /home/arnd/arm-soc/lib/test_hexdump.c:116:3:
include/linux/fortify-string.h:108:33: error: '__builtin_strncpy' output truncated copying between 0 and 32 bytes from a string of length 32 [-Werror=stringop-truncation]
  108 | #define __underlying_strncpy    __builtin_strncpy
      |                                 ^
include/linux/fortify-string.h:187:16: note: in expansion of macro '__underlying_strncpy'
  187 |         return __underlying_strncpy(p, q, size);
      |                ^~~~~~~~~~~~~~~~~~~~

As far as I can tell, this is harmless here because the truncation is
intentional, but using strscpy_pad() will avoid the warning since gcc
does not (yet) know about it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 lib/test_hexdump.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
index b916801f23a8..c9820122af56 100644
--- a/lib/test_hexdump.c
+++ b/lib/test_hexdump.c
@@ -113,7 +113,7 @@ static void __init test_hexdump_prepare_test(size_t len, int rowsize,
 			*p++ = ' ';
 		} while (p < test + rs * 2 + rs / gs + 1);
 
-		strncpy(p, data_a, l);
+		strscpy_pad(p, data_a, l);
 		p += l;
 	}
 
-- 
2.39.2


  parent reply	other threads:[~2024-03-28 14:06 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-28 14:04 [PATCH 00/11] address remaining stringop-truncation warnings Arnd Bergmann
2024-03-28 14:04 ` [PATCH 01/11] staging: vc04_services: changen strncpy() to strscpy_pad() Arnd Bergmann
2024-03-28 14:42   ` Dan Carpenter
2024-03-28 16:15     ` Arnd Bergmann
2024-03-28 23:10   ` Justin Stitt
2024-03-28 14:04 ` [PATCH 02/11] scsi: devinfo: rework scsi_strcpy_devinfo() Arnd Bergmann
2024-03-28 16:46   ` Bart Van Assche
2024-03-28 23:14   ` Justin Stitt
2024-03-28 23:18     ` Arnd Bergmann
2024-03-28 14:04 ` [PATCH 03/11] staging: replace weird strncpy() with memcpy() Arnd Bergmann
2024-03-28 16:35   ` Dan Carpenter
2024-04-08 14:45     ` Arnd Bergmann
2024-04-08 15:59       ` Dan Carpenter
2024-04-08 19:20         ` Arnd Bergmann
2024-03-28 14:04 ` [PATCH 04/11] orangefs: convert strncpy() to strscpy() Arnd Bergmann
2024-03-28 23:17   ` Justin Stitt
2024-03-28 14:04 ` Arnd Bergmann [this message]
2024-03-28 23:54   ` [PATCH 05/11] test_hexdump: avoid string truncation warning Justin Stitt
2024-04-08 15:38     ` Arnd Bergmann
2024-04-08 19:53       ` Justin Stitt
2024-03-28 14:04 ` [PATCH 06/11] acpi: avoid warning for truncated string copy Arnd Bergmann
2024-03-28 23:20   ` Justin Stitt
2024-04-08 14:41   ` Rafael J. Wysocki
2024-03-28 14:04 ` [PATCH 07/11] block/partitions/ldm: convert strncpy() to strscpy() Arnd Bergmann
2024-03-28 23:24   ` Justin Stitt
2024-03-28 14:04 ` [PATCH 08/11] blktrace: convert strncpy() to strscpy_pad() Arnd Bergmann
2024-03-28 14:14   ` Steven Rostedt
2024-04-08 18:05     ` Arnd Bergmann
2024-03-28 14:04 ` [PATCH 09/11] staging: rtl8723bs: convert strncpy to strscpy Arnd Bergmann
2024-03-28 23:01   ` Justin Stitt
2024-04-08 18:15     ` Arnd Bergmann
2024-03-28 14:04 ` [PATCH 10/11] staging: greybus: change strncpy() to strscpy() Arnd Bergmann
2024-03-28 15:00   ` Dan Carpenter
2024-04-08 18:26     ` Arnd Bergmann
2024-04-09  7:09       ` Dan Carpenter
2024-03-28 23:28   ` Justin Stitt
2024-04-08 18:30     ` Arnd Bergmann
2024-03-28 14:04 ` [PATCH 11/11] kbuild: enable -Wstringop-truncation globally Arnd Bergmann

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