Validate the output buffer length for L2CAP config reqs and resps to avoid stack buffer overflowing. CVE-2017-1000251. See bug #6308404.9-51

2 files changed, 361 insertions, 0 deletions

diff --git a/0000_README b/0000_README
index e403e79a..728edf0b 100644
--- a/0000_README
+++ b/0000_README
@@ -259,6 +259,10 @@ Patch:  2300_enable-poweroff-on-Mac-Pro-11.patch
 From:   http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/patch/drivers/pci/quirks.c?id=5080ff61a438f3dd80b88b423e1a20791d8a774c
 Desc:   Workaround to enable poweroff on Mac Pro 11. See bug #601964.
 
+Patch:  2400_BT-check-L2CAP-buffer-length.patch
+From:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e860d2c904d1a9f38a24eb44c9f34b8f915a6ea3
+Desc:   Validate the output buffer length for L2CAP config reqs and resps to avoid stack buffer overflowing. CVE-2017-1000251. See bug #630840
+
 Patch:  2900_dev-root-proc-mount-fix.patch
 From:   https://bugs.gentoo.org/show_bug.cgi?id=438380
 Desc:   Ensure that /dev/root doesn't appear in /proc/mounts when bootint without an initramfs.
diff --git a/2400_BT-check-L2CAP-buffer-length.patch b/2400_BT-check-L2CAP-buffer-length.patch
new file mode 100644
index 00000000..c6bfdf71
--- /dev/null
+++ b/2400_BT-check-L2CAP-buffer-length.patch
@@ -0,0 +1,357 @@
+From e860d2c904d1a9f38a24eb44c9f34b8f915a6ea3 Mon Sep 17 00:00:00 2001
+From: Ben Seri <ben@armis.com>
+Date: Sat, 9 Sep 2017 23:15:59 +0200
+Subject: Bluetooth: Properly check L2CAP config option output buffer length
+
+Validate the output buffer length for L2CAP config requests and responses
+to avoid overflowing the stack buffer used for building the option blocks.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Ben Seri <ben@armis.com>
+Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+---
+ net/bluetooth/l2cap_core.c | 80 +++++++++++++++++++++++++---------------------
+ 1 file changed, 43 insertions(+), 37 deletions(-)
+
+diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
+index 303c779..43ba91c 100644
+--- a/net/bluetooth/l2cap_core.c
++++ b/net/bluetooth/l2cap_core.c
+@@ -58,7 +58,7 @@ static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
+ 				       u8 code, u8 ident, u16 dlen, void *data);
+ static void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len,
+ 			   void *data);
+-static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data);
++static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data, size_t data_size);
+ static void l2cap_send_disconn_req(struct l2cap_chan *chan, int err);
+ 
+ static void l2cap_tx(struct l2cap_chan *chan, struct l2cap_ctrl *control,
+@@ -1473,7 +1473,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
+ 
+ 			set_bit(CONF_REQ_SENT, &chan->conf_state);
+ 			l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
+-				       l2cap_build_conf_req(chan, buf), buf);
++				       l2cap_build_conf_req(chan, buf, sizeof(buf)), buf);
+ 			chan->num_conf_req++;
+ 		}
+ 
+@@ -2987,12 +2987,15 @@ static inline int l2cap_get_conf_opt(void **ptr, int *type, int *olen,
+ 	return len;
+ }
+ 
+-static void l2cap_add_conf_opt(void **ptr, u8 type, u8 len, unsigned long val)
++static void l2cap_add_conf_opt(void **ptr, u8 type, u8 len, unsigned long val, size_t size)
+ {
+ 	struct l2cap_conf_opt *opt = *ptr;
+ 
+ 	BT_DBG("type 0x%2.2x len %u val 0x%lx", type, len, val);
+ 
++	if (size < L2CAP_CONF_OPT_SIZE + len)
++		return;
++
+ 	opt->type = type;
+ 	opt->len  = len;
+ 
+@@ -3017,7 +3020,7 @@ static void l2cap_add_conf_opt(void **ptr, u8 type, u8 len, unsigned long val)
+ 	*ptr += L2CAP_CONF_OPT_SIZE + len;
+ }
+ 
+-static void l2cap_add_opt_efs(void **ptr, struct l2cap_chan *chan)
++static void l2cap_add_opt_efs(void **ptr, struct l2cap_chan *chan, size_t size)
+ {
+ 	struct l2cap_conf_efs efs;
+ 
+@@ -3045,7 +3048,7 @@ static void l2cap_add_opt_efs(void **ptr, struct l2cap_chan *chan)
+ 	}
+ 
+ 	l2cap_add_conf_opt(ptr, L2CAP_CONF_EFS, sizeof(efs),
+-			   (unsigned long) &efs);
++			   (unsigned long) &efs, size);
+ }
+ 
+ static void l2cap_ack_timeout(struct work_struct *work)
+@@ -3191,11 +3194,12 @@ static inline void l2cap_txwin_setup(struct l2cap_chan *chan)
+ 	chan->ack_win = chan->tx_win;
+ }
+ 
+-static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data)
++static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data, size_t data_size)
+ {
+ 	struct l2cap_conf_req *req = data;
+ 	struct l2cap_conf_rfc rfc = { .mode = chan->mode };
+ 	void *ptr = req->data;
++	void *endptr = data + data_size;
+ 	u16 size;
+ 
+ 	BT_DBG("chan %p", chan);
+@@ -3220,7 +3224,7 @@ static int l2cap_build_conf_req(struct l2cap_chan *chan, void *data)
+ 
+ done:
+ 	if (chan->imtu != L2CAP_DEFAULT_MTU)
+-		l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->imtu);
++		l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->imtu, endptr - ptr);
+ 
+ 	switch (chan->mode) {
+ 	case L2CAP_MODE_BASIC:
+@@ -3239,7 +3243,7 @@ done:
+ 		rfc.max_pdu_size    = 0;
+ 
+ 		l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc),
+-				   (unsigned long) &rfc);
++				   (unsigned long) &rfc, endptr - ptr);
+ 		break;
+ 
+ 	case L2CAP_MODE_ERTM:
+@@ -3259,21 +3263,21 @@ done:
+ 				       L2CAP_DEFAULT_TX_WINDOW);
+ 
+ 		l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc),
+-				   (unsigned long) &rfc);
++				   (unsigned long) &rfc, endptr - ptr);
+ 
+ 		if (test_bit(FLAG_EFS_ENABLE, &chan->flags))
+-			l2cap_add_opt_efs(&ptr, chan);
++			l2cap_add_opt_efs(&ptr, chan, endptr - ptr);
+ 
+ 		if (test_bit(FLAG_EXT_CTRL, &chan->flags))
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_EWS, 2,
+-					   chan->tx_win);
++					   chan->tx_win, endptr - ptr);
+ 
+ 		if (chan->conn->feat_mask & L2CAP_FEAT_FCS)
+ 			if (chan->fcs == L2CAP_FCS_NONE ||
+ 			    test_bit(CONF_RECV_NO_FCS, &chan->conf_state)) {
+ 				chan->fcs = L2CAP_FCS_NONE;
+ 				l2cap_add_conf_opt(&ptr, L2CAP_CONF_FCS, 1,
+-						   chan->fcs);
++						   chan->fcs, endptr - ptr);
+ 			}
+ 		break;
+ 
+@@ -3291,17 +3295,17 @@ done:
+ 		rfc.max_pdu_size = cpu_to_le16(size);
+ 
+ 		l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc),
+-				   (unsigned long) &rfc);
++				   (unsigned long) &rfc, endptr - ptr);
+ 
+ 		if (test_bit(FLAG_EFS_ENABLE, &chan->flags))
+-			l2cap_add_opt_efs(&ptr, chan);
++			l2cap_add_opt_efs(&ptr, chan, endptr - ptr);
+ 
+ 		if (chan->conn->feat_mask & L2CAP_FEAT_FCS)
+ 			if (chan->fcs == L2CAP_FCS_NONE ||
+ 			    test_bit(CONF_RECV_NO_FCS, &chan->conf_state)) {
+ 				chan->fcs = L2CAP_FCS_NONE;
+ 				l2cap_add_conf_opt(&ptr, L2CAP_CONF_FCS, 1,
+-						   chan->fcs);
++						   chan->fcs, endptr - ptr);
+ 			}
+ 		break;
+ 	}
+@@ -3312,10 +3316,11 @@ done:
+ 	return ptr - data;
+ }
+ 
+-static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data)
++static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data_size)
+ {
+ 	struct l2cap_conf_rsp *rsp = data;
+ 	void *ptr = rsp->data;
++	void *endptr = data + data_size;
+ 	void *req = chan->conf_req;
+ 	int len = chan->conf_len;
+ 	int type, hint, olen;
+@@ -3417,7 +3422,7 @@ done:
+ 			return -ECONNREFUSED;
+ 
+ 		l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc),
+-				   (unsigned long) &rfc);
++				   (unsigned long) &rfc, endptr - ptr);
+ 	}
+ 
+ 	if (result == L2CAP_CONF_SUCCESS) {
+@@ -3430,7 +3435,7 @@ done:
+ 			chan->omtu = mtu;
+ 			set_bit(CONF_MTU_DONE, &chan->conf_state);
+ 		}
+-		l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->omtu);
++		l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->omtu, endptr - ptr);
+ 
+ 		if (remote_efs) {
+ 			if (chan->local_stype != L2CAP_SERV_NOTRAFIC &&
+@@ -3444,7 +3449,7 @@ done:
+ 
+ 				l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS,
+ 						   sizeof(efs),
+-						   (unsigned long) &efs);
++						   (unsigned long) &efs, endptr - ptr);
+ 			} else {
+ 				/* Send PENDING Conf Rsp */
+ 				result = L2CAP_CONF_PENDING;
+@@ -3477,7 +3482,7 @@ done:
+ 			set_bit(CONF_MODE_DONE, &chan->conf_state);
+ 
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
+-					   sizeof(rfc), (unsigned long) &rfc);
++					   sizeof(rfc), (unsigned long) &rfc, endptr - ptr);
+ 
+ 			if (test_bit(FLAG_EFS_ENABLE, &chan->flags)) {
+ 				chan->remote_id = efs.id;
+@@ -3491,7 +3496,7 @@ done:
+ 					le32_to_cpu(efs.sdu_itime);
+ 				l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS,
+ 						   sizeof(efs),
+-						   (unsigned long) &efs);
++						   (unsigned long) &efs, endptr - ptr);
+ 			}
+ 			break;
+ 
+@@ -3505,7 +3510,7 @@ done:
+ 			set_bit(CONF_MODE_DONE, &chan->conf_state);
+ 
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC, sizeof(rfc),
+-					   (unsigned long) &rfc);
++					   (unsigned long) &rfc, endptr - ptr);
+ 
+ 			break;
+ 
+@@ -3527,10 +3532,11 @@ done:
+ }
+ 
+ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
+-				void *data, u16 *result)
++				void *data, size_t size, u16 *result)
+ {
+ 	struct l2cap_conf_req *req = data;
+ 	void *ptr = req->data;
++	void *endptr = data + size;
+ 	int type, olen;
+ 	unsigned long val;
+ 	struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_BASIC };
+@@ -3548,13 +3554,13 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
+ 				chan->imtu = L2CAP_DEFAULT_MIN_MTU;
+ 			} else
+ 				chan->imtu = val;
+-			l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->imtu);
++			l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, chan->imtu, endptr - ptr);
+ 			break;
+ 
+ 		case L2CAP_CONF_FLUSH_TO:
+ 			chan->flush_to = val;
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_FLUSH_TO,
+-					   2, chan->flush_to);
++					   2, chan->flush_to, endptr - ptr);
+ 			break;
+ 
+ 		case L2CAP_CONF_RFC:
+@@ -3568,13 +3574,13 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
+ 			chan->fcs = 0;
+ 
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
+-					   sizeof(rfc), (unsigned long) &rfc);
++					   sizeof(rfc), (unsigned long) &rfc, endptr - ptr);
+ 			break;
+ 
+ 		case L2CAP_CONF_EWS:
+ 			chan->ack_win = min_t(u16, val, chan->ack_win);
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_EWS, 2,
+-					   chan->tx_win);
++					   chan->tx_win, endptr - ptr);
+ 			break;
+ 
+ 		case L2CAP_CONF_EFS:
+@@ -3587,7 +3593,7 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len,
+ 				return -ECONNREFUSED;
+ 
+ 			l2cap_add_conf_opt(&ptr, L2CAP_CONF_EFS, sizeof(efs),
+-					   (unsigned long) &efs);
++					   (unsigned long) &efs, endptr - ptr);
+ 			break;
+ 
+ 		case L2CAP_CONF_FCS:
+@@ -3692,7 +3698,7 @@ void __l2cap_connect_rsp_defer(struct l2cap_chan *chan)
+ 		return;
+ 
+ 	l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
+-		       l2cap_build_conf_req(chan, buf), buf);
++		       l2cap_build_conf_req(chan, buf, sizeof(buf)), buf);
+ 	chan->num_conf_req++;
+ }
+ 
+@@ -3900,7 +3906,7 @@ sendresp:
+ 		u8 buf[128];
+ 		set_bit(CONF_REQ_SENT, &chan->conf_state);
+ 		l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
+-			       l2cap_build_conf_req(chan, buf), buf);
++			       l2cap_build_conf_req(chan, buf, sizeof(buf)), buf);
+ 		chan->num_conf_req++;
+ 	}
+ 
+@@ -3978,7 +3984,7 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
+ 			break;
+ 
+ 		l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
+-			       l2cap_build_conf_req(chan, req), req);
++			       l2cap_build_conf_req(chan, req, sizeof(req)), req);
+ 		chan->num_conf_req++;
+ 		break;
+ 
+@@ -4090,7 +4096,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
+ 	}
+ 
+ 	/* Complete config. */
+-	len = l2cap_parse_conf_req(chan, rsp);
++	len = l2cap_parse_conf_req(chan, rsp, sizeof(rsp));
+ 	if (len < 0) {
+ 		l2cap_send_disconn_req(chan, ECONNRESET);
+ 		goto unlock;
+@@ -4124,7 +4130,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
+ 	if (!test_and_set_bit(CONF_REQ_SENT, &chan->conf_state)) {
+ 		u8 buf[64];
+ 		l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
+-			       l2cap_build_conf_req(chan, buf), buf);
++			       l2cap_build_conf_req(chan, buf, sizeof(buf)), buf);
+ 		chan->num_conf_req++;
+ 	}
+ 
+@@ -4184,7 +4190,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn,
+ 			char buf[64];
+ 
+ 			len = l2cap_parse_conf_rsp(chan, rsp->data, len,
+-						   buf, &result);
++						   buf, sizeof(buf), &result);
+ 			if (len < 0) {
+ 				l2cap_send_disconn_req(chan, ECONNRESET);
+ 				goto done;
+@@ -4214,7 +4220,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn,
+ 			/* throw out any old stored conf requests */
+ 			result = L2CAP_CONF_SUCCESS;
+ 			len = l2cap_parse_conf_rsp(chan, rsp->data, len,
+-						   req, &result);
++						   req, sizeof(req), &result);
+ 			if (len < 0) {
+ 				l2cap_send_disconn_req(chan, ECONNRESET);
+ 				goto done;
+@@ -4791,7 +4797,7 @@ static void l2cap_do_create(struct l2cap_chan *chan, int result,
+ 			set_bit(CONF_REQ_SENT, &chan->conf_state);
+ 			l2cap_send_cmd(chan->conn, l2cap_get_ident(chan->conn),
+ 				       L2CAP_CONF_REQ,
+-				       l2cap_build_conf_req(chan, buf), buf);
++				       l2cap_build_conf_req(chan, buf, sizeof(buf)), buf);
+ 			chan->num_conf_req++;
+ 		}
+ 	}
+@@ -7465,7 +7471,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
+ 				set_bit(CONF_REQ_SENT, &chan->conf_state);
+ 				l2cap_send_cmd(conn, l2cap_get_ident(conn),
+ 					       L2CAP_CONF_REQ,
+-					       l2cap_build_conf_req(chan, buf),
++					       l2cap_build_conf_req(chan, buf, sizeof(buf)),
+ 					       buf);
+ 				chan->num_conf_req++;
+ 			}
+-- 
+cgit v1.1
+