Re: [PATCH] policycoreutils/secon: fix discarded-qualifiers warning with glibc 2.43

[Petr Lautrbach <lautrbach@redhat.com>]

Petr Lautrbach <lautrbach@redhat.com> writes:

> From: Dustin Kirkland <dustin.kirkland@chainguard.dev>
>
> In my_getXcon_raw(), ptr is declared as const char * but is assigned
> from fgets(), which returns char *. With glibc 2.43, strchr(const char
> *, int) now returns const char *, so the subsequent assignment to
> char *tmp triggers:
>
>   secon.c:365:18: error: initialization discards 'const' qualifier
>   from pointer target type [-Werror=discarded-qualifiers]
>
> The const on ptr was always incorrect: fgets() returns a mutable
> pointer into buf (a char[4096]), and the result of strchr() through
> ptr is written to via *tmp = 0. Remove the erroneous const.
>
> This is the same class of bug reported in issue #506
> (libselinux/src/selinux_config.c:284). The fix here is analogous:
> the variable should not have been const-qualified in the first place.
>
> Signed-off-by: Dustin Kirkland <dustin.kirkland@chainguard.dev>

Acked-by: Petr Lautrbach <lautrbach@redhat.com>


> ---
>
> Resent of the original patch downloaded from githu as the original patch in the
> email was slightly broken.
>
>  policycoreutils/secon/secon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/policycoreutils/secon/secon.c b/policycoreutils/secon/secon.c
> index d624fa136f3e..9a05cf1959ba 100644
> --- a/policycoreutils/secon/secon.c
> +++ b/policycoreutils/secon/secon.c
> @@ -348,7 +348,7 @@ static int my_getXcon_raw(pid_t pid, char  **con, const char *val)
>  {
>  	char buf[4096];
>  	FILE *fp = NULL;
> -	const char *ptr = NULL;
> +	char *ptr = NULL;
>  
>  	snprintf(buf, sizeof(buf), "%s/%ld/attr/%s", "/proc", (long int)pid,
>  		 val);
> -- 
> 2.54.0