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authorStefan Richter <stefanr@s5r6.in-berlin.de>2016-10-29 21:28:18 +0200
committerSasha Levin <alexander.levin@verizon.com>2016-11-23 23:09:29 -0500
commitdff462fc98d649a51557491d02f5c16f2127970b (patch)
tree69edd091c922e5a91cb71ca232f706f2bfec2c22
parent056bcad97c8e1ac7f6287a45b090ea51f93565cf (diff)
downloadlinux-linaro-stable-dff462fc98d649a51557491d02f5c16f2127970b.tar.gz
firewire: net: guard against rx buffer overflows
[ Upstream commit 667121ace9dbafb368618dbabcf07901c962ddac ] 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@gmail.com> Reviewed-by: Eyal Itkin <eyal.itkin@gmail.com> Fixes: CVE 2016-8633 Cc: stable@vger.kernel.org Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--drivers/firewire/net.c51
1 files changed, 35 insertions, 16 deletions
diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index 2c68da1ceeee..a5cbfd1a6ee5 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -591,6 +591,9 @@ static int fwnet_incoming_packet(struct fwnet_device *dev, __be32 *buf, int len,
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) {
@@ -615,7 +618,12 @@ static int fwnet_incoming_packet(struct fwnet_device *dev, __be32 *buf, int len,
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;
@@ -629,6 +637,9 @@ static int fwnet_incoming_packet(struct fwnet_device *dev, __be32 *buf, int len,
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);
@@ -735,6 +746,22 @@ static void fwnet_receive_packet(struct fw_card *card, struct fw_request *r,
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)
{
@@ -744,9 +771,6 @@ static void fwnet_receive_broadcast(struct fw_iso_context *context,
__be32 *buf_ptr;
int retval;
u32 length;
- u16 source_node_id;
- u32 specifier_id;
- u32 ver;
unsigned long offset;
unsigned long flags;
@@ -763,22 +787,17 @@ static void fwnet_receive_broadcast(struct fw_iso_context *context,
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;