[PATCH v6 1/4] fs: unicode: Use strscpy() instead of strncpy()

From: Shreeya Patel
Date: Wed Mar 31 2021 - 17:08:52 EST


Following warning was reported by Kernel Test Robot.

In function 'utf8_parse_version',
inlined from 'utf8_load' at fs/unicode/utf8mod.c:195:7:
>> fs/unicode/utf8mod.c:175:2: warning: 'strncpy' specified bound 12 equals
destination size [-Wstringop-truncation]
175 | strncpy(version_string, version, sizeof(version_string));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The -Wstringop-truncation warning highlights the unintended
uses of the strncpy function that truncate the terminating NULL
character from the source string.
Unlike strncpy(), strscpy() always null-terminates the destination string,
hence use strscpy() instead of strncpy().

Fixes: 9d53690f0d4e5 (unicode: implement higher level API for string handling)
Acked-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Signed-off-by: Shreeya Patel <shreeya.patel@xxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
---
fs/unicode/utf8-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
index dc25823bfed9..f9e6a2718aba 100644
--- a/fs/unicode/utf8-core.c
+++ b/fs/unicode/utf8-core.c
@@ -179,8 +179,10 @@ static int utf8_parse_version(const char *version, unsigned int *maj,
{1, "%d.%d.%d"},
{0, NULL}
};
+ int ret = strscpy(version_string, version, sizeof(version_string));

- strncpy(version_string, version, sizeof(version_string));
+ if (ret < 0)
+ return ret;

if (match_token(version_string, token, args) != 1)
return -EINVAL;
--
2.30.2