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SubjectRe: [PATCH v2 3/4] fs: unicode: Use strscpy() instead of strncpy()
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On 18/03/21 7:03 pm, Shreeya Patel wrote:
> 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().


Not sure if strscpy is preferable. Just found this article
https://lwn.net/Articles/659214/
Should I go for memcpy instead?


>
> Signed-off-by: Shreeya Patel <shreeya.patel@collabora.com>
> Reported-by: kernel test robot <lkp@intel.com>
> ---
> Changes in v2
> - Resolve warning of -Wstringop-truncation reported by
> kernel test robot.
>
> fs/unicode/unicode-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/unicode/unicode-core.c b/fs/unicode/unicode-core.c
> index d5f09e022ac5..287a8a48836c 100644
> --- a/fs/unicode/unicode-core.c
> +++ b/fs/unicode/unicode-core.c
> @@ -179,7 +179,7 @@ static int unicode_parse_version(const char *version, unsigned int *maj,
> {0, NULL}
> };
>
> - strncpy(version_string, version, sizeof(version_string));
> + strscpy(version_string, version, sizeof(version_string));
>
> if (match_token(version_string, token, args) != 1)
> return -EINVAL;

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