Re: [PATCH v2] selftests/capabilities: Fix possible file leak in copy_fromat_to

[Shuah Khan <skhan@linuxfoundation.org>]

On 6/26/24 19:57, Ma Ke wrote:
> The open() function returns -1 on error. openat() and open() initialize
> 'from' and 'to', and only 'from' validated with 'if' statement. If the
> initialization of variable 'to' fails, we should better check the value
> of 'to' and close 'from' to avoid possible file leak. Improve the checking
> of 'from' additionally.
> 
> Fixes: 32ae976ed3b5 ("selftests/capabilities: Add tests for capability evolution")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>
> ---
> Changes in v2:
> - modified the patch according to suggestions;
> - found by customized static analysis tool.

Care to give more details on this customized static analysis
tool?

> ---
>   tools/testing/selftests/capabilities/test_execve.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/capabilities/test_execve.c b/tools/testing/selftests/capabilities/test_execve.c
> index 47bad7ddc5bc..6406ab6aa1f5 100644
> --- a/tools/testing/selftests/capabilities/test_execve.c
> +++ b/tools/testing/selftests/capabilities/test_execve.c
> @@ -145,10 +145,14 @@ static void chdir_to_tmpfs(void)
>   static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
>   {
>   	int from = openat(fromfd, fromname, O_RDONLY);
> -	if (from == -1)
> +	if (from < 0)
>   		ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));
>   
>   	int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
> +	if (to < 0) {
> +		close(from);
> +		ksft_exit_fail_msg("open copy destination - %s\n", strerror(errno));
> +	}
>   
>   	while (true) {
>   		char buf[4096];

thanks,
-- Shuah