linux-kernel - Re: [syzbot] Re: [syzbot] [bpf?] [net?] KASAN: slab-use-after-free Read in bq_xmit

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Message-ID: <000000000000859970061dc1e9b7@google.com>
Date: Sun, 21 Jul 2024 06:29:03 -0700
From: syzbot <syzbot+707d98c8649695eaf329@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Re: [syzbot] Re: [syzbot] [bpf?] [net?] KASAN: slab-use-after-free
 Read in bq_xmit_all

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***

Subject: Re: [syzbot] [bpf?] [net?] KASAN: slab-use-after-free Read in bq_xmit_all
Author: aha310510@...il.com

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 kernel/bpf/cpumap.c | 2 +-
 kernel/bpf/devmap.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index fbdf5a1aabfe..8fccc311397c 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -676,7 +676,7 @@ static void bq_flush_to_queue(struct xdp_bulk_queue *bq)
 	struct ptr_ring *q;
 	int i;
 
-	if (unlikely(!bq->count))
+	if (unlikely(!bq->count) || unlikely(bq->count) > CPU_MAP_BULK_SIZE)
 		return;
 
 	q = rcpu->queue;
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 9e0e3b0a18e4..4b9203deb711 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -378,7 +378,7 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
 	int to_send = cnt;
 	int i;
 
-	if (unlikely(!cnt))
+	if (unlikely(!cnt) || unlikely(cnt) > DEV_MAP_BULK_SIZE)
 		return;
 
 	for (i = 0; i < cnt; i++) {
--