3.13.11-ckt24 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>
commit 8a70cefa3037d62e7c0b6068a66675def1a330c9 upstream.
The AF_IEEE802154 sockaddr looks like this:
struct sockaddr_ieee802154 {
sa_family_t family; /* AF_IEEE802154 */
struct ieee802154_addr_sa addr;
};
struct ieee802154_addr_sa {
int addr_type;
u16 pan_id;
union {
u8 hwaddr[IEEE802154_ADDR_LEN];
u16 short_addr;
};
};
On most architectures there will be implicit structure padding here,
in two different places:
* In struct sockaddr_ieee802154, two bytes of padding between 'family'
(unsigned short) and 'addr', so that 'addr' starts on a four byte
boundary.
* In struct ieee802154_addr_sa, two bytes at the end of the structure,
to make the structure 16 bytes.
When calling recvmsg(2) on a PF_IEEE802154 SOCK_DGRAM socket, the
ieee802154 stack constructs a struct sockaddr_ieee802154 on the
kernel stack without clearing these padding fields, and, depending
on the addr_type, between four and ten bytes of uncleared kernel
stack will be copied to userspace.
We can't just insert two 'u16 __pad's in the right places and zero
those before copying an address to userspace, as not all architectures
insert this implicit padding -- from a quick test it seems that avr32,
cris and m68k don't insert this padding, while every other architecture
that I have cross compilers for does insert this padding.
The easiest way to plug the leak is to just memset the whole struct
sockaddr_ieee802154 before filling in the fields we want to fill in,
and that's what this patch does.
Signed-off-by: Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>
Acked-by: Alexander Aring <alex.aring@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
[ luis: backported to 3.16:
- file rename: net/ieee802154/socket.c -> net/ieee802154/dgram.c ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
net/ieee802154/dgram.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/ieee802154/dgram.c b/net/ieee802154/dgram.c
index 1865fdf..2bdd0cc 100644
--- a/net/ieee802154/dgram.c
+++ b/net/ieee802154/dgram.c
@@ -313,6 +313,12 @@ static int dgram_recvmsg(struct kiocb *iocb, struct sock *sk,
sock_recv_ts_and_drops(msg, sk, skb);
if (saddr) {
+ /* Clear the implicit padding in struct sockaddr_ieee802154
+ * (16 bits between 'family' and 'addr') and in struct
+ * ieee802154_addr_sa (16 bits at the end of the structure).
+ */
+ memset(saddr, 0, sizeof(*saddr));
+
saddr->family = AF_IEEE802154;
saddr->addr = mac_cb(skb)->sa;
*addr_len = sizeof(*saddr);
--
1.9.1
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