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authorHawkins Jiawei <yin31149@gmail.com>2022-10-18 10:18:51 +0800
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2022-10-18 12:51:03 -0700
commit97097c85c088e11651146da32a4e1cdb9dfa6193 (patch)
tree3f884883faef9d7e7d0754d07b9b79044d9bbee7
parent42cf46dea905a80f6de218e837ba4d4cc33d6979 (diff)
downloadbluetooth-next-97097c85c088e11651146da32a4e1cdb9dfa6193.tar.gz
Bluetooth: L2CAP: Fix memory leak in vhci_write
Notice: this object is not reachable from any branch.
Syzkaller reports a memory leak as follows: ==================================== BUG: memory leak unreferenced object 0xffff88810d81ac00 (size 240): [...] 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: [<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418 [<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline] [<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline] [<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline] [<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511 [<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline] [<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline] [<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578 [<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631 [<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd ==================================== HCI core will uses hci_rx_work() to process frame, which is queued to the hdev->rx_q tail in hci_recv_frame() by HCI driver. Yet the problem is that, HCI core may not free the skb after handling ACL data packets. To be more specific, when start fragment does not contain the L2CAP length, HCI core just copies skb into conn->rx_skb and finishes frame process in l2cap_recv_acldata(), without freeing the skb, which triggers the above memory leak. This patch solves it by releasing the relative skb, after processing the above case in l2cap_recv_acldata(). Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length") Link: https://lore.kernel.org/all/0000000000000d0b1905e6aaef64@google.com/ Reported-and-tested-by: syzbot+8f819e36e01022991cfa@syzkaller.appspotmail.com Signed-off-by: Hawkins Jiawei <yin31149@gmail.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Notice: this object is not reachable from any branch.
-rw-r--r--net/bluetooth/l2cap_core.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 9a32ce6349194..1fbe087d6ae4e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -8461,9 +8461,8 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
* expected length.
*/
if (skb->len < L2CAP_LEN_SIZE) {
- if (l2cap_recv_frag(conn, skb, conn->mtu) < 0)
- goto drop;
- return;
+ l2cap_recv_frag(conn, skb, conn->mtu);
+ break;
}
len = get_unaligned_le16(skb->data) + L2CAP_HDR_SIZE;
@@ -8507,7 +8506,7 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
/* Header still could not be read just continue */
if (conn->rx_skb->len < L2CAP_LEN_SIZE)
- return;
+ break;
}
if (skb->len > conn->rx_len) {