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Subject[PATCH 4.4 099/132] Bluetooth: Fix invalid-free in bcsp_close()
Date
From: Tomas Bortoli <tomasbortoli@gmail.com>

commit cf94da6f502d8caecabd56b194541c873c8a7a3c upstream.

Syzbot reported an invalid-free that I introduced fixing a memleak.

bcsp_recv() also frees bcsp->rx_skb but never nullifies its value.
Nullify bcsp->rx_skb every time it is freed.

Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+a0d209a4676664613e76@syzkaller.appspotmail.com
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/bluetooth/hci_bcsp.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/bluetooth/hci_bcsp.c
+++ b/drivers/bluetooth/hci_bcsp.c
@@ -566,6 +566,7 @@ static int bcsp_recv(struct hci_uart *hu
if (*ptr == 0xc0) {
BT_ERR("Short BCSP packet");
kfree_skb(bcsp->rx_skb);
+ bcsp->rx_skb = NULL;
bcsp->rx_state = BCSP_W4_PKT_START;
bcsp->rx_count = 0;
} else
@@ -581,6 +582,7 @@ static int bcsp_recv(struct hci_uart *hu
bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
BT_ERR("Error in BCSP hdr checksum");
kfree_skb(bcsp->rx_skb);
+ bcsp->rx_skb = NULL;
bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
bcsp->rx_count = 0;
continue;
@@ -615,6 +617,7 @@ static int bcsp_recv(struct hci_uart *hu
bscp_get_crc(bcsp));

kfree_skb(bcsp->rx_skb);
+ bcsp->rx_skb = NULL;
bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
bcsp->rx_count = 0;
continue;

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