[PATCH 4.9 15/62] NFC: nci: fix memory leak in nci_rx_data_packet()

Greg Kroah-Hartman
2022-12-05T19:12:46Z

From: Liu Shixin <liushixin2@huawei.com>

[ Upstream commit 53270fb0fd77fe786d8c07a0793981d797836b93 ]

Syzbot reported a memory leak about skb:

unreferenced object 0xffff88810e144e00 (size 240):
comm "syz-executor284", pid 3701, jiffies 4294952403 (age 12.620s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff83ab79a9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:497
[<ffffffff82a5cf64>] alloc_skb include/linux/skbuff.h:1267 [inline]
[<ffffffff82a5cf64>] virtual_ncidev_write+0x24/0xe0 drivers/nfc/virtual_ncidev.c:116
[<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:759 [inline]
[<ffffffff815f6503>] do_loop_readv_writev fs/read_write.c:743 [inline]
[<ffffffff815f6503>] do_iter_write+0x253/0x300 fs/read_write.c:863
[<ffffffff815f66ed>] vfs_writev+0xdd/0x240 fs/read_write.c:934
[<ffffffff815f68f6>] do_writev+0xa6/0x1c0 fs/read_write.c:977
[<ffffffff848802d5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff848802d5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84a00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

In nci_rx_data_packet(), if we don't get a valid conn_info, we will return
directly but forget to release the skb.

Reported-by: syzbot+cdb9a427d1bc08815104@syzkaller.appspotmail.com
Fixes: 4aeee6871e8c ("NFC: nci: Add dynamic logical connections support")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Link: https://lore.kernel.org/r/20221118082419.239475-1-liushixin2@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/nfc/nci/data.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index b8a295dd15d8..45b654dca6f9 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -291,8 +291,10 @@ void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
nci_plen(skb->data));

conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
- if (!conn_info)
+ if (!conn_info) {
+ kfree_skb(skb);
return;
+ }

/* strip the nci data header */
skb_pull(skb, NCI_DATA_HDR_SIZE);
--
2.35.1