From f8eb26dda8bfc806ff71f65966dc17210686fc20 Mon Sep 17 00:00:00 2001 From: Xiaolong Ye Date: Sat, 13 Jun 2020 23:49:17 +0800 Subject: [PATCH] mbuf: fix boundary check at dynamic field registration 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: stable@dpdk.org Signed-off-by: Xiaolong Ye Acked-by: Olivier Matz --- 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 953e3ec31c..13d6da6d16 100644 --- a/lib/librte_mbuf/rte_mbuf_dyn.c +++ b/lib/librte_mbuf/rte_mbuf_dyn.c @@ -69,7 +69,8 @@ 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; -- 2.20.1