This is a note to let you know that I've just added the patch titled
firewire: net: guard against rx buffer overflows
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
firewire-net-guard-against-rx-buffer-overflows.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 667121ace9dbafb368618dbabcf07901c962ddac Mon Sep 17 00:00:00 2001
From: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Date: Sat, 29 Oct 2016 21:28:18 +0200
Subject: firewire: net: guard against rx buffer overflows
From: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
commit 667121ace9dbafb368618dbabcf07901c962ddac upstream.
The IP-over-1394 driver firewire-net lacked input validation when
handling incoming fragmented datagrams. A maliciously formed fragment
with a respectively large datagram_offset would cause a memcpy past the
datagram buffer.
So, drop any packets carrying a fragment with offset + length larger
than datagram_size.
In addition, ensure that
- GASP header, unfragmented encapsulation header, or fragment
encapsulation header actually exists before we access it,
- the encapsulated datagram or fragment is of nonzero size.
Reported-by: Eyal Itkin <eyal.itkin@xxxxxxxxx>
Reviewed-by: Eyal Itkin <eyal.itkin@xxxxxxxxx>
Fixes: CVE 2016-8633
Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firewire/net.c | 51 +++++++++++++++++++++++++++++++++----------------
1 file changed, 35 insertions(+), 16 deletions(-)
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -578,6 +578,9 @@ static int fwnet_incoming_packet(struct
int retval;
u16 ether_type;
+ if (len <= RFC2374_UNFRAG_HDR_SIZE)
+ return 0;
+
hdr.w0 = be32_to_cpu(buf[0]);
lf = fwnet_get_hdr_lf(&hdr);
if (lf == RFC2374_HDR_UNFRAG) {
@@ -602,7 +605,12 @@ static int fwnet_incoming_packet(struct
return fwnet_finish_incoming_packet(net, skb, source_node_id,
is_broadcast, ether_type);
}
+
/* A datagram fragment has been received, now the fun begins. */
+
+ if (len <= RFC2374_FRAG_HDR_SIZE)
+ return 0;
+
hdr.w1 = ntohl(buf[1]);
buf += 2;
len -= RFC2374_FRAG_HDR_SIZE;
@@ -616,6 +624,9 @@ static int fwnet_incoming_packet(struct
datagram_label = fwnet_get_hdr_dgl(&hdr);
dg_size = fwnet_get_hdr_dg_size(&hdr); /* ??? + 1 */
+ if (fg_off + len > dg_size)
+ return 0;
+
spin_lock_irqsave(&dev->lock, flags);
peer = fwnet_peer_find_by_node_id(dev, source_node_id, generation);
@@ -722,6 +733,22 @@ static void fwnet_receive_packet(struct
fw_send_response(card, r, rcode);
}
+static int gasp_source_id(__be32 *p)
+{
+ return be32_to_cpu(p[0]) >> 16;
+}
+
+static u32 gasp_specifier_id(__be32 *p)
+{
+ return (be32_to_cpu(p[0]) & 0xffff) << 8 |
+ (be32_to_cpu(p[1]) & 0xff000000) >> 24;
+}
+
+static u32 gasp_version(__be32 *p)
+{
+ return be32_to_cpu(p[1]) & 0xffffff;
+}
+
static void fwnet_receive_broadcast(struct fw_iso_context *context,
u32 cycle, size_t header_length, void *header, void *data)
{
@@ -731,9 +758,6 @@ static void fwnet_receive_broadcast(stru
__be32 *buf_ptr;
int retval;
u32 length;
- u16 source_node_id;
- u32 specifier_id;
- u32 ver;
unsigned long offset;
unsigned long flags;
@@ -750,22 +774,17 @@ static void fwnet_receive_broadcast(stru
spin_unlock_irqrestore(&dev->lock, flags);
- specifier_id = (be32_to_cpu(buf_ptr[0]) & 0xffff) << 8
- | (be32_to_cpu(buf_ptr[1]) & 0xff000000) >> 24;
- ver = be32_to_cpu(buf_ptr[1]) & 0xffffff;
- source_node_id = be32_to_cpu(buf_ptr[0]) >> 16;
-
- if (specifier_id == IANA_SPECIFIER_ID &&
- (ver == RFC2734_SW_VERSION
+ if (length > IEEE1394_GASP_HDR_SIZE &&
+ gasp_specifier_id(buf_ptr) == IANA_SPECIFIER_ID &&
+ (gasp_version(buf_ptr) == RFC2734_SW_VERSION
#if IS_ENABLED(CONFIG_IPV6)
- || ver == RFC3146_SW_VERSION
+ || gasp_version(buf_ptr) == RFC3146_SW_VERSION
#endif
- )) {
- buf_ptr += 2;
- length -= IEEE1394_GASP_HDR_SIZE;
- fwnet_incoming_packet(dev, buf_ptr, length, source_node_id,
+ ))
+ fwnet_incoming_packet(dev, buf_ptr + 2,
+ length - IEEE1394_GASP_HDR_SIZE,
+ gasp_source_id(buf_ptr),
context->card->generation, true);
- }
packet.payload_length = dev->rcv_buffer_size;
packet.interrupt = 1;
Patches currently in stable-queue which might be from stefanr@xxxxxxxxxxxxxxxxx are
queue-4.4/firewire-net-fix-fragmented-datagram_size-off-by-one.patch
queue-4.4/firewire-net-guard-against-rx-buffer-overflows.patch
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