qcacmn: Fix possible OOB read in cnss_diag_cmd_handler

The nla_data coming from user space is a variable length data,
but the driver is checking nla_len() against a fixed length struct only.
It is possible that the nla_len() check against fixed length struct
may pass and if the nla_data does not have the payload and it may
result in possible out-of-bound read (slot->payload).

Hence the fix is to, check if nla_len() is atleast more than
the fixed length struct and also account for payload length.

Change-Id: I2e68d55c0411cff55908c1704031e3c070f3316e
CRs-Fixed: 2825763
This commit is contained in:
Srinivas Girigowda 2020-12-02 17:50:19 -08:00 committed by snandini
parent 4e87e6c554
commit f7248d774e

View File

@ -4224,6 +4224,7 @@ static void cnss_diag_cmd_handler(const void *data, int data_len,
{ {
struct dbglog_slot *slot = NULL; struct dbglog_slot *slot = NULL;
struct nlattr *tb[QCA_WLAN_VENDOR_ATTR_MAX + 1]; struct nlattr *tb[QCA_WLAN_VENDOR_ATTR_MAX + 1];
int len;
/* /*
* audit note: it is ok to pass a NULL policy here since a * audit note: it is ok to pass a NULL policy here since a
@ -4242,15 +4243,17 @@ static void cnss_diag_cmd_handler(const void *data, int data_len,
return; return;
} }
if (nla_len(tb[CLD80211_ATTR_DATA]) != sizeof(struct dbglog_slot)) { len = nla_len(tb[CLD80211_ATTR_DATA]);
AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("%s: attr length check fails\n", if (len < sizeof(struct dbglog_slot)) {
AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("%s: attr length less than sizeof(struct dbglog_slot)\n",
__func__)); __func__));
return; return;
} }
slot = (struct dbglog_slot *)nla_data(tb[CLD80211_ATTR_DATA]);
if (!slot) { slot = (struct dbglog_slot *)nla_data(tb[CLD80211_ATTR_DATA]);
AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("%s: data NULL\n", __func__)); if (len != (sizeof(struct dbglog_slot) + (uint64_t) slot->length)) {
AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("%s: attr length check fails\n",
__func__));
return; return;
} }