ptp: prevent string overflow

The ida_alloc_max() function can return up to INT_MAX so this buffer is
not large enough.  Also use snprintf() for extra safety.

Fixes: 403376ddb422 ("ptp: add debugfs interface to see applied channel masks")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/d4b1a995-a0cb-4125-aa1d-5fd5044aba1d@moroto.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 2e801cd..3d1b0a9 100644 (file)
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -220,7 +220,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
        struct ptp_clock *ptp;
        struct timestamp_event_queue *queue = NULL;
        int err = 0, index, major = MAJOR(ptp_devt);
-       char debugfsname[8];
+       char debugfsname[16];
        size_t size;
 
        if (info->n_alarm > PTP_MAX_ALARMS)
@@ -343,7 +343,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
        }
 
        /* Debugfs initialization */
-       sprintf(debugfsname, "ptp%d", ptp->index);
+       snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
        ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
 
        return ptp;