[dpdk-dev] [PATCH v4] net/i40e: fix the core dump risk of wild pointer operation

[Wei Zhao]

In i40e PMD code of function i40e_res_pool_free(), if valid_entry
is freed by "rte_free(valid_entry);" in the code, then the following
code for pool update may still use the wild pointer "valid_entry"
for pool info update. It seems has the risk of core dump for
using wild pointer operation, we should avoid this risk.

Cc: sta...@dpdk.org
Fixes: 4861cde46116 ("i40e: new poll mode driver")

Signed-off-by: Wei Zhao <wei.zh...@intel.com>

---

v2:
update commit log

v3:
set free pointer to NULL

v4:
change code style
---
 drivers/net/i40e/i40e_ethdev.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
index 749d85f54..679d59e5d 100644
--- a/drivers/net/i40e/i40e_ethdev.c
+++ b/drivers/net/i40e/i40e_ethdev.c
@@ -4935,6 +4935,7 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
 {
        struct pool_entry *entry, *next, *prev, *valid_entry = NULL;
        uint32_t pool_offset;
+       uint16_t len;
        int insert;
 
        if (pool == NULL) {
@@ -4973,12 +4974,13 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
        }
 
        insert = 0;
+       len = valid_entry->len;
        /* Try to merge with next one*/
        if (next != NULL) {
                /* Merge with next one */
-               if (valid_entry->base + valid_entry->len == next->base) {
+               if (valid_entry->base + len == next->base) {
                        next->base = valid_entry->base;
-                       next->len += valid_entry->len;
+                       next->len += len;
                        rte_free(valid_entry);
                        valid_entry = next;
                        insert = 1;
@@ -4987,14 +4989,16 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
 
        if (prev != NULL) {
                /* Merge with previous one */
-               if (prev->base + prev->len == valid_entry->base) {
-                       prev->len += valid_entry->len;
+               if (prev->base + len == valid_entry->base) {
+                       prev->len += len;
                        /* If it merge with next one, remove next node */
                        if (insert == 1) {
                                LIST_REMOVE(valid_entry, next);
                                rte_free(valid_entry);
+                               valid_entry = NULL;
                        } else {
                                rte_free(valid_entry);
+                               valid_entry = NULL;
                                insert = 1;
                        }
                }
@@ -5010,8 +5014,8 @@ i40e_res_pool_free(struct i40e_res_pool_info *pool,
                        LIST_INSERT_HEAD(&pool->free_list, valid_entry, next);
        }
 
-       pool->num_free += valid_entry->len;
-       pool->num_alloc -= valid_entry->len;
+       pool->num_free += len;
+       pool->num_alloc -= len;
 
        return 0;
 }
-- 
2.19.1