We should make sure off + size < sizeof(struct rte_mbuf) to avoid
possible out-of-bounds access of free_space array, there is no issue
currently due to the low bits of free_flags (which is adjacent to
free_space) are always set to 0. But we shouldn't rely on it since it's
fragile and layout of struct mbuf_dyn_shm may be changed in the future.
This patch adds boundary check explicitly to avoid potential risk of
out-of-bounds access.
Fixes: 4958ca3a443a ("mbuf: support dynamic fields and flags")
Cc: sta...@dpdk.org
Signed-off-by: Xiaolong Ye <xiaolong...@intel.com>
---
V3: update subject as Olivier suggested
lib/librte_mbuf/rte_mbuf_dyn.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/librte_mbuf/rte_mbuf_dyn.c b/lib/librte_mbuf/rte_mbuf_dyn.c
index d6931f847..9d6388cff 100644
--- a/lib/librte_mbuf/rte_mbuf_dyn.c
+++ b/lib/librte_mbuf/rte_mbuf_dyn.c
@@ -71,7 +71,8 @@ process_score(void)
for (off = 0; off < sizeof(struct rte_mbuf); off++) {
/* get the size of the free zone */
- for (size = 0; shm->free_space[off + size]; size++)
+ for (size = 0; (off + size) < sizeof(struct rte_mbuf) &&
+ shm->free_space[off + size]; size++)
;
if (size == 0)
continue;
--
2.17.1
