[PATCH v2] net/i40e: validate raw flow items before dereferencing

[Ciara Loftus]

When a RTE_FLOW_ITEM_TYPE_RAW item is used with a non-zero length,
the spec and mask pattern pointers are dereferenced unconditionally
in a loop, causing a segfault if either is NULL. Additionally, no
check is made that the spec and mask have equal lengths before
iterating, which could result in out-of-bounds access.

Add validation before the loop: reject the item if either pattern
pointer is NULL, or if the spec and mask lengths differ.

Bugzilla ID: 1155
Fixes: 6ced3dd72f5f ("net/i40e: support flexible payload parsing for FDIR")
Cc: stable at dpdk.org

Signed-off-by: Ciara Loftus <ciara.loftus at intel.com>
---
v2:
* Add an additional check for spec and mask length mismatch
---
 drivers/net/intel/i40e/i40e_flow.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/net/intel/i40e/i40e_flow.c b/drivers/net/intel/i40e/i40e_flow.c
index 2374b9bbca..4624edc758 100644
--- a/drivers/net/intel/i40e/i40e_flow.c
+++ b/drivers/net/intel/i40e/i40e_flow.c
@@ -2350,6 +2350,30 @@ i40e_flow_parse_fdir_pattern(struct rte_eth_dev *dev,
 				return -rte_errno;
 			}
 
+			if (raw_spec->length != 0) {
+				if (raw_spec->pattern == NULL) {
+					rte_flow_error_set(error, EINVAL,
+							   RTE_FLOW_ERROR_TYPE_ITEM,
+							   item,
+							   "NULL RAW spec pattern");
+					return -rte_errno;
+				}
+				if (raw_mask->pattern == NULL) {
+					rte_flow_error_set(error, EINVAL,
+							   RTE_FLOW_ERROR_TYPE_ITEM,
+							   item,
+							   "NULL RAW mask pattern");
+					return -rte_errno;
+				}
+				if (raw_spec->length != raw_mask->length) {
+					rte_flow_error_set(error, EINVAL,
+							   RTE_FLOW_ERROR_TYPE_ITEM,
+							   item,
+							   "RAW spec and mask length mismatch");
+					return -rte_errno;
+				}
+			}
+
 			for (i = 0; i < raw_spec->length; i++) {
 				j = i + next_dst_off;
 				if (j >= RTE_ETH_FDIR_MAX_FLEXLEN ||
-- 
2.43.0