[PATCH net v3] bnxt_en: validate firmware backing store types

[Pengpeng Hou <pengpeng@iscas.ac.cn>]

bnxt_hwrm_func_backing_store_qcaps_v2() stores resp->type from the
firmware response in ctxm->type and later uses that value to index
fixed backing-store metadata arrays such as ctx_arr[] and
bnxt_bstore_to_trace[] without a local range check.

Validate the returned type before storing it and abort the query when
firmware reports a type outside BNXT_CTX_V2_MAX. Keep next_valid_type in
a dedicated variable so loop control stays clear for non-valid or
unchanged entries while resp->type is validated directly before use.

Fixes: 6a4d0774f02d ("bnxt_en: Add support for new backing store query firmware API")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
v3:
- mark the patch for net
- add a Fixes tag
- replace resp_type with next_type for loop control and validate resp->type directly

 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 0751c0e4581a..59ddf7a0c0ba 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -8692,6 +8692,7 @@ static int bnxt_hwrm_func_backing_store_qcaps_v2(struct bnxt *bp)
 		u8 init_val, init_off, i;
 		u32 max_entries;
 		u16 entry_size;
+		u16 next_type;
 		__le32 *p;
 		u32 flags;
 
@@ -8700,7 +8701,7 @@ static int bnxt_hwrm_func_backing_store_qcaps_v2(struct bnxt *bp)
 		if (rc)
 			goto ctx_done;
 		flags = le32_to_cpu(resp->flags);
-		type = le16_to_cpu(resp->next_valid_type);
+		next_type = le16_to_cpu(resp->next_valid_type);
 		if (!(flags & BNXT_CTX_MEM_TYPE_VALID)) {
 			bnxt_free_one_ctx_mem(bp, ctxm, true);
 			continue;
@@ -8708,12 +8709,21 @@ static int bnxt_hwrm_func_backing_store_qcaps_v2(struct bnxt *bp)
 		entry_size = le16_to_cpu(resp->entry_size);
 		max_entries = le32_to_cpu(resp->max_num_entries);
 		if (ctxm->mem_valid) {
-			if (!(flags & BNXT_CTX_MEM_PERSIST) ||
-			    ctxm->entry_size != entry_size ||
-			    ctxm->max_entries != max_entries)
-				bnxt_free_one_ctx_mem(bp, ctxm, true);
-			else
+			if ((flags & BNXT_CTX_MEM_PERSIST) &&
+			    ctxm->entry_size == entry_size &&
+			    ctxm->max_entries == max_entries) {
+				type = next_type;
 				continue;
+			}
+
+			bnxt_free_one_ctx_mem(bp, ctxm, true);
+		}
+		if (le16_to_cpu(resp->type) >= BNXT_CTX_V2_MAX) {
+			netdev_warn(bp->dev,
+				    "invalid backing store type %u returned by firmware\n",
+				    le16_to_cpu(resp->type));
+			rc = -EINVAL;
+			goto ctx_done;
 		}
 		ctxm->type = le16_to_cpu(resp->type);
 		ctxm->entry_size = entry_size;
@@ -8731,6 +8741,8 @@ static int bnxt_hwrm_func_backing_store_qcaps_v2(struct bnxt *bp)
 		for (i = 0, p = &resp->split_entry_0; i < ctxm->split_entry_cnt;
 		     i++, p++)
 			ctxm->split[i] = le32_to_cpu(*p);
+
+		type = next_type;
 	}
 	rc = bnxt_alloc_all_ctx_pg_info(bp, BNXT_CTX_V2_MAX);
 
-- 
2.50.1 (Apple Git-155)