[PATCH net-next 1/2] nfp: flower: check that we don't exceed the FW key size

[Simon Horman]

From: Louis Peens <louis.pe...@netronome.com>

Add a check to make sure the total length of the flow key sent to the
firmware stays within the supported limit.

Signed-off-by: Louis Peens <louis.pe...@netronome.com>
Signed-off-by: Simon Horman <simon.hor...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/flower/main.h  |  2 ++
 drivers/net/ethernet/netronome/nfp/flower/match.c | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.h 
b/drivers/net/ethernet/netronome/nfp/flower/main.h
index 3bf9c1afa45e..4924a217f5ba 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.h
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.h
@@ -30,6 +30,8 @@ struct nfp_app;
 #define NFP_FLOWER_MASK_ELEMENT_RS     1
 #define NFP_FLOWER_MASK_HASH_BITS      10
 
+#define NFP_FLOWER_KEY_MAX_LW          32
+
 #define NFP_FL_META_FLAG_MANAGE_MASK   BIT(7)
 
 #define NFP_FL_MASK_REUSE_TIME_NS      40000
diff --git a/drivers/net/ethernet/netronome/nfp/flower/match.c 
b/drivers/net/ethernet/netronome/nfp/flower/match.c
index f7f01e2e3dce..64690511e47b 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/match.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/match.c
@@ -434,6 +434,7 @@ int nfp_flower_compile_flow_match(struct nfp_app *app,
 {
        struct flow_rule *rule = flow_cls_offload_flow_rule(flow);
        u32 port_id;
+       int ext_len;
        int err;
        u8 *ext;
        u8 *msk;
@@ -589,5 +590,15 @@ int nfp_flower_compile_flow_match(struct nfp_app *app,
                }
        }
 
+       /* Check that the flow key does not exceed the maximum limit.
+        * All structures in the key is multiples of 4 bytes, so use u32.
+        */
+       ext_len = (u32 *)ext - (u32 *)nfp_flow->unmasked_data;
+       if (ext_len > NFP_FLOWER_KEY_MAX_LW) {
+               NL_SET_ERR_MSG_MOD(extack,
+                                  "unsupported offload: flow key too long");
+               return -EOPNOTSUPP;
+       }
+
        return 0;
 }
-- 
2.20.1