[ 059/135] Bluetooth: HCI - Fix info leak in getsockopt(HCI_FILTER)

[Ben Hutchings]

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

[ Upstream commit e15ca9a0ef9a86f0477530b0f44a725d67f889ee ]

The HCI code fails to initialize the two padding bytes of struct
hci_ufilter before copying it to userland -- that for leaking two
bytes kernel stack. Add an explicit memset(0) before filling the
structure to avoid the info leak.

Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/bluetooth/hci_sock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index f6afe3d..e4c8bc0 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -671,6 +671,7 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname, char
 		{
 			struct hci_filter *f = &hci_pi(sk)->filter;
 
+			memset(&uf, 0, sizeof(uf));
 			uf.type_mask = f->type_mask;
 			uf.opcode    = f->opcode;
 			uf.event_mask[0] = *((u32 *) f->event_mask + 0);


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