From: Tomas Bortoli <tomasbortoli@gmail.com>
To: marcel@holtmann.org, johan.hedberg@gmail.com
Cc: linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller@googlegroups.com,
Tomas Bortoli <tomasbortoli@gmail.com>,
syzbot+a0d209a4676664613e76@syzkaller.appspotmail.com
Subject: [PATCH] Fix invalid-free in bcsp_close()
Date: Fri, 1 Nov 2019 21:42:44 +0100 [thread overview]
Message-ID: <20191101204244.14509-1-tomasbortoli@gmail.com> (raw)
In-Reply-To: <000000000000109f9605964acf6c@google.com>
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
---
drivers/bluetooth/hci_bcsp.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c
index fe2e307009f4..cf4a56095817 100644
--- a/drivers/bluetooth/hci_bcsp.c
+++ b/drivers/bluetooth/hci_bcsp.c
@@ -591,6 +591,7 @@ static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
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
@@ -606,6 +607,7 @@ static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
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;
@@ -630,6 +632,7 @@ static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
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;
--
2.20.1
next prev parent reply other threads:[~2019-11-01 20:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 15:42 KASAN: invalid-free in skb_free_head syzbot
2019-11-01 20:42 ` Tomas Bortoli [this message]
2019-11-04 14:19 ` [PATCH] Fix invalid-free in bcsp_close() Marcel Holtmann
2019-11-25 12:40 ` Alexander Potapenko
2019-11-26 6:18 ` Marcel Holtmann
2019-11-26 8:12 ` Greg Kroah-Hartman
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