From: Ziyang Xuan <william.xuanziyang@huawei.com>
To: <mani@kernel.org>, <davem@davemloft.net>, <edumazet@google.com>,
<kuba@kernel.org>, <pabeni@redhat.com>,
<linux-arm-msm@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: [PATCH net v2] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
Date: Mon, 10 Apr 2023 09:23:52 +0800 [thread overview]
Message-ID: <20230410012352.3997823-1-william.xuanziyang@huawei.com> (raw)
Syzbot reported a bug as following:
=====================================================
BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
call_write_iter include/linux/fs.h:2189 [inline]
aio_write+0x63a/0x950 fs/aio.c:1600
io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
__do_sys_io_submit fs/aio.c:2078 [inline]
__se_sys_io_submit+0x293/0x770 fs/aio.c:2048
__x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was created at:
slab_post_alloc_hook mm/slab.h:766 [inline]
slab_alloc_node mm/slub.c:3452 [inline]
__kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
__do_kmalloc_node mm/slab_common.c:967 [inline]
__kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
kmalloc_reserve net/core/skbuff.c:492 [inline]
__alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
__netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
call_write_iter include/linux/fs.h:2189 [inline]
aio_write+0x63a/0x950 fs/aio.c:1600
io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
__do_sys_io_submit fs/aio.c:2078 [inline]
__se_sys_io_submit+0x293/0x770 fs/aio.c:2048
__x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
scenario. This triggers the uninit variable access bug.
Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
qrtr_endpoint_post() to fix the bug.
Fixes: 5fdeb0d372ab ("net: qrtr: Implement outgoing flow control")
Reported-by: syzbot+4436c9630a45820fda76@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=c14607f0963d27d5a3d5f4c8639b500909e43540
Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
v2:
- Combine QRTR_TYPE_NEW_SERVER and QRTR_TYPE_RESUME_TX size check.
---
net/qrtr/af_qrtr.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
index 3a70255c8d02..76f0434d3d06 100644
--- a/net/qrtr/af_qrtr.c
+++ b/net/qrtr/af_qrtr.c
@@ -498,6 +498,11 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
if (!size || len != ALIGN(size, 4) + hdrlen)
goto err;
+ if ((cb->type == QRTR_TYPE_NEW_SERVER ||
+ cb->type == QRTR_TYPE_RESUME_TX) &&
+ size < sizeof(struct qrtr_ctrl_pkt))
+ goto err;
+
if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA &&
cb->type != QRTR_TYPE_RESUME_TX)
goto err;
@@ -510,9 +515,6 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
/* Remote node endpoint can bridge other distant nodes */
const struct qrtr_ctrl_pkt *pkt;
- if (size < sizeof(*pkt))
- goto err;
-
pkt = data + hdrlen;
qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
}
--
2.25.1
next reply other threads:[~2023-04-10 1:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-10 1:23 Ziyang Xuan [this message]
2023-04-10 8:20 ` [PATCH net v2] net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume() Simon Horman
2023-04-13 7:50 ` patchwork-bot+netdevbpf
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