msm: IPA: add the check on intf query

The ipa_ioc_query_intf_rx_props structure comes
from the ioctl handler, and it is verified that
the size of rx buffer does not exceed the
IPA_NUM_PROPS_MAX elements. It is also verified
that the "entry->rx" buffer does not exceed
IPA_NUM_PROPS_MAX when "entry" is allocated.
However, the sizes of the buffer "rx->rx" and
the buffer "entry->rx" are not guaranteed to
be the same and will lead memory corruption
issue. The fix is to add the check before
memcpy.

Change-Id: Idf5c2d32f47c1a1cffeaa5607193855188893ddb
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

FPIIM-835

Change-Id: I141524f6666face115c919678472bf066441e5ab
diff --git a/drivers/platform/msm/ipa/ipa_intf.c b/drivers/platform/msm/ipa/ipa_intf.c
index ea5c97f..96c27c3 100644
--- a/drivers/platform/msm/ipa/ipa_intf.c
+++ b/drivers/platform/msm/ipa/ipa_intf.c
@@ -210,6 +210,14 @@
 	mutex_lock(&ipa_ctx->lock);
 	list_for_each_entry(entry, &ipa_ctx->intf_list, link) {
 		if (!strncmp(entry->name, tx->name, IPA_RESOURCE_NAME_MAX)) {
+			/* add the entry check */
+			if (entry->num_tx_props != tx->num_tx_props) {
+				IPAERR("invalid entry number(%u %u)\n",
+					entry->num_tx_props,
+						tx->num_tx_props);
+				mutex_unlock(&ipa_ctx->lock);
+				return result;
+			}
 			memcpy(tx->tx, entry->tx, entry->num_tx_props *
 			       sizeof(struct ipa_ioc_tx_intf_prop));
 			result = 0;
@@ -243,6 +251,14 @@
 	mutex_lock(&ipa_ctx->lock);
 	list_for_each_entry(entry, &ipa_ctx->intf_list, link) {
 		if (!strncmp(entry->name, rx->name, IPA_RESOURCE_NAME_MAX)) {
+			/* add the entry check */
+			if (entry->num_rx_props != rx->num_rx_props) {
+				IPAERR("invalid entry number(%u %u)\n",
+					entry->num_rx_props,
+						rx->num_rx_props);
+				mutex_unlock(&ipa_ctx->lock);
+				return result;
+			}
 			memcpy(rx->rx, entry->rx, entry->num_rx_props *
 					sizeof(struct ipa_ioc_rx_intf_prop));
 			result = 0;