On Mon, May 17, 2021 at 11:27:25PM +0200, mwilck@xxxxxxxx wrote:
> From: Martin Wilck <mwilck@xxxxxxxx>
>
> By setting (*reply)[19] = '\0', we always truncated a possible
> ":aptpl" suffix. Fix it, and use the return value of snprintf()
> as length.
>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> ---
> multipathd/cli_handlers.c | 17 ++++++++---------
> 1 file changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/multipathd/cli_handlers.c b/multipathd/cli_handlers.c
> index 9606494..59d44b4 100644
> --- a/multipathd/cli_handlers.c
> +++ b/multipathd/cli_handlers.c
> @@ -1540,7 +1540,7 @@ cli_getprkey(void * v, char ** reply, int * len, void * data)
> struct multipath * mpp;
> struct vectors * vecs = (struct vectors *)data;
> char *mapname = get_keyparam(v, MAP);
> - char *flagstr = "";
> + uint64_t key;
>
> mapname = convert_dev(mapname, 0);
> condlog(3, "%s: get persistent reservation key (operator)", mapname);
> @@ -1553,17 +1553,16 @@ cli_getprkey(void * v, char ** reply, int * len, void * data)
> if (!*reply)
> return 1;
>
> - if (!get_be64(mpp->reservation_key)) {
> + key = get_be64(mpp->reservation_key);
> + if (!key) {
> sprintf(*reply, "none\n");
> - *len = strlen(*reply) + 1;
> + *len = sizeof("none\n");
> return 0;
> }
> - if (mpp->sa_flags & MPATH_F_APTPL_MASK)
> - flagstr = ":aptpl";
> - snprintf(*reply, 26, "0x%" PRIx64 "%s\n",
> - get_be64(mpp->reservation_key), flagstr);
> - (*reply)[19] = '\0';
> - *len = strlen(*reply) + 1;
> +
> + /* This snprintf() can't overflow - PRIx64 needs max 16 chars */
> + *len = snprintf(*reply, 26, "0x%" PRIx64 "%s\n", key,
> + mpp->sa_flags & MPATH_F_APTPL_MASK ? ":aptpl" : "") + 1;
> return 0;
> }
>
> --
> 2.31.1
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