libertas: Fix two buffer overflows at parsing bss descriptor

add_ie_rates() copys rates without checking the length
in bss descriptor from remote AP.when victim connects to
remote attacker, this may trigger buffer overflow.
lbs_ibss_join_existing() copys rates without checking the length
in bss descriptor from remote IBSS node.when victim connects to
remote attacker, this may trigger buffer overflow.
Fix them by putting the length check before performing copy.

This fix addresses CVE-2019-14896 and CVE-2019-14897.
This also fix build warning of mixed declarations and code.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Wen Huang <huangwenabc@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/marvell/libertas/cfg.c b/drivers/net/wireless/marvell/libertas/cfg.c
index 57edfada0665fda7ec68b7f60128eef3af9a5219..c9401c121a14e6dfd11d41aca19fb8d4f25b706b 100644 (file)
--- a/drivers/net/wireless/marvell/libertas/cfg.c
+++ b/drivers/net/wireless/marvell/libertas/cfg.c
@@ -273,6 +273,10 @@ add_ie_rates(u8 *tlv, const u8 *ie, int *nrates)
        int hw, ap, ap_max = ie[1];
        u8 hw_rate;
 
+       if (ap_max > MAX_RATES) {
+               lbs_deb_assoc("invalid rates\n");
+               return tlv;
+       }
        /* Advance past IE header */
        ie += 2;
 
@@ -1717,6 +1721,9 @@ static int lbs_ibss_join_existing(struct lbs_private *priv,
        struct cmd_ds_802_11_ad_hoc_join cmd;
        u8 preamble = RADIO_PREAMBLE_SHORT;
        int ret = 0;
+       int hw, i;
+       u8 rates_max;
+       u8 *rates;
 
        /* TODO: set preamble based on scan result */
        ret = lbs_set_radio(priv, preamble, 1);
@@ -1775,9 +1782,12 @@ static int lbs_ibss_join_existing(struct lbs_private *priv,
        if (!rates_eid) {
                lbs_add_rates(cmd.bss.rates);
        } else {
-               int hw, i;
-               u8 rates_max = rates_eid[1];
-               u8 *rates = cmd.bss.rates;
+               rates_max = rates_eid[1];
+               if (rates_max > MAX_RATES) {
+                       lbs_deb_join("invalid rates");
+                       goto out;
+               }
+               rates = cmd.bss.rates;
                for (hw = 0; hw < ARRAY_SIZE(lbs_rates); hw++) {
                        u8 hw_rate = lbs_rates[hw].bitrate / 5;
                        for (i = 0; i < rates_max; i++) {