AP MLD: Add NULL check for mld pointer during MLD link removal

MLD control interface creation failed randomly because the existing
control interface was not properly cleaned up. During the failure case
handling, the memory allocated for hapd->mld is freed in
hostapd_bss_setup_multi_link(). Subsequently, when performing MLD link
removal during the interface down, hostapd_mld_remove_link() attempts to
access the mld pointer without NULL check, causing a segmentation fault.

To prevent this issue, add a validation to check if the mld pointer
is NULL before accessing it.

Signed-off-by: Govindaraj Saminathan <quic_gsaminat@quicinc.com>

diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index c8751a247941e40bfea8c59135f9e7728e16f809..dc50ad1bcc9a66a50c5eddc86cba62ba756adc3f 100644 (file)
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -633,7 +633,7 @@ static void hostapd_bss_link_deinit(struct hostapd_data *hapd)
        }
 
        /* Put all freeing logic above this */
-       if (!hapd->mld->num_links)
+       if (!hapd->mld || !hapd->mld->num_links)
                return;
 
        /* If not started, not yet linked to the MLD. However, the first