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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	syzbot+355cab184197dbbfa384@syzkaller.appspotmail.com,
	Sven Eckelmann <sven@narfation.org>,
	Antonio Quartulli <a@unstable.cc>,
	Simon Wunderlich <sw@simonwunderlich.de>
Subject: [PATCH 5.2 17/37] batman-adv: Only read OGM tvlv_len after buffer len check
Date: Fri, 13 Sep 2019 14:07:22 +0100
Message-ID: <20190913130518.242128562@linuxfoundation.org> (raw)
In-Reply-To: <20190913130510.727515099@linuxfoundation.org>

From: Sven Eckelmann <sven@narfation.org>

commit a15d56a60760aa9dbe26343b9a0ac5228f35d445 upstream.

Multiple batadv_ogm_packet can be stored in an skbuff. The functions
batadv_iv_ogm_send_to_if()/batadv_iv_ogm_receive() use
batadv_iv_ogm_aggr_packet() to check if there is another additional
batadv_ogm_packet in the skb or not before they continue processing the
packet.

The length for such an OGM is BATADV_OGM_HLEN +
batadv_ogm_packet->tvlv_len. The check must first check that at least
BATADV_OGM_HLEN bytes are available before it accesses tvlv_len (which is
part of the header. Otherwise it might try read outside of the currently
available skbuff to get the content of tvlv_len.

Fixes: ef26157747d4 ("batman-adv: tvlv - basic infrastructure")
Reported-by: syzbot+355cab184197dbbfa384@syzkaller.appspotmail.com
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Acked-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/batman-adv/bat_iv_ogm.c |   20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -277,17 +277,23 @@ static u8 batadv_hop_penalty(u8 tq, cons
  * batadv_iv_ogm_aggr_packet() - checks if there is another OGM attached
  * @buff_pos: current position in the skb
  * @packet_len: total length of the skb
- * @tvlv_len: tvlv length of the previously considered OGM
+ * @ogm_packet: potential OGM in buffer
  *
  * Return: true if there is enough space for another OGM, false otherwise.
  */
-static bool batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len,
-				      __be16 tvlv_len)
+static bool
+batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len,
+			  const struct batadv_ogm_packet *ogm_packet)
 {
 	int next_buff_pos = 0;
 
-	next_buff_pos += buff_pos + BATADV_OGM_HLEN;
-	next_buff_pos += ntohs(tvlv_len);
+	/* check if there is enough space for the header */
+	next_buff_pos += buff_pos + sizeof(*ogm_packet);
+	if (next_buff_pos > packet_len)
+		return false;
+
+	/* check if there is enough space for the optional TVLV */
+	next_buff_pos += ntohs(ogm_packet->tvlv_len);
 
 	return (next_buff_pos <= packet_len) &&
 	       (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
@@ -315,7 +321,7 @@ static void batadv_iv_ogm_send_to_if(str
 
 	/* adjust all flags and log packets */
 	while (batadv_iv_ogm_aggr_packet(buff_pos, forw_packet->packet_len,
-					 batadv_ogm_packet->tvlv_len)) {
+					 batadv_ogm_packet)) {
 		/* we might have aggregated direct link packets with an
 		 * ordinary base packet
 		 */
@@ -1704,7 +1710,7 @@ static int batadv_iv_ogm_receive(struct
 
 	/* unpack the aggregated packets and process them one by one */
 	while (batadv_iv_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
-					 ogm_packet->tvlv_len)) {
+					 ogm_packet)) {
 		batadv_iv_ogm_process(skb, ogm_offset, if_incoming);
 
 		ogm_offset += BATADV_OGM_HLEN;



  parent reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 13:07 [PATCH 5.2 00/37] 5.2.15-stable review Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 01/37] gpio: pca953x: correct type of reg_direction Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 02/37] gpio: pca953x: use pca953x_read_regs instead of regmap_bulk_read Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 03/37] ALSA: hda - Fix potential endless loop at applying quirks Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 04/37] ALSA: hda/realtek - Fix overridden device-specific initialization Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 05/37] ALSA: hda/realtek - Add quirk for HP Pavilion 15 Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 06/37] ALSA: hda/realtek - Enable internal speaker & headset mic of ASUS UX431FL Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 07/37] ALSA: hda/realtek - Fix the problem of two front mics on a ThinkCentre Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 08/37] sched/fair: Dont assign runtime for throttled cfs_rq Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 09/37] drm/vmwgfx: Fix double free in vmw_recv_msg() Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 10/37] drm/nouveau/sec2/gp102: add missing MODULE_FIRMWAREs Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 11/37] vhost/test: fix build for vhost test Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 12/37] vhost/test: fix build for vhost test - again Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 13/37] powerpc/64e: Drop stale call to smp_processor_id() which hangs SMP startup Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 14/37] powerpc/tm: Fix FP/VMX unavailable exceptions inside a transaction Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 15/37] powerpc/tm: Fix restoring FP/VMX facility incorrectly on interrupts Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 16/37] batman-adv: fix uninit-value in batadv_netlink_get_ifindex() Greg Kroah-Hartman
2019-09-13 13:07 ` Greg Kroah-Hartman [this message]
2019-09-13 13:07 ` [PATCH 5.2 18/37] bcache: only clear BTREE_NODE_dirty bit when it is set Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 19/37] bcache: add comments for mutex_lock(&b->write_lock) Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 20/37] bcache: fix race in btree_flush_write() Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 21/37] IB/rdmavt: Add new completion inline Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 22/37] IB/{rdmavt, qib, hfi1}: Convert to new completion API Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 23/37] IB/hfi1: Unreserve a flushed OPFN request Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 24/37] drm/i915: Disable SAMPLER_STATE prefetching on all Gen11 steppings Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 25/37] drm/i915: Make sure cdclk is high enough for DP audio on VLV/CHV Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 26/37] mmc: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 27/37] usb: chipidea: imx: add imx7ulp support Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 28/37] usb: chipidea: imx: fix EPROBE_DEFER support during driver probe Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 29/37] virtio/s390: fix race on airq_areas[] Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 30/37] drm/i915: Support flags in whitlist WAs Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 31/37] drm/i915: Support whitelist workarounds on all engines Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 32/37] drm/i915: whitelist PS_(DEPTH|INVOCATION)_COUNT Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 33/37] drm/i915: Add whitelist workarounds for ICL Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 34/37] drm/i915/icl: whitelist PS_(DEPTH|INVOCATION)_COUNT Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 35/37] Btrfs: fix unwritten extent buffers and hangs on future writeback attempts Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 36/37] vhost: block speculation of translated descriptors Greg Kroah-Hartman
2019-09-14  0:54   ` Stefan Lippers-Hollmann
2019-09-14  5:50     ` Greg Kroah-Hartman
2019-09-14  7:15       ` Stefan Lippers-Hollmann
2019-09-14  8:08         ` Greg Kroah-Hartman
2019-09-15  9:34           ` Thomas Backlund
2019-09-15 13:37             ` Greg Kroah-Hartman
2019-09-13 13:07 ` [PATCH 5.2 37/37] vhost: make sure log_num < in_num Greg Kroah-Hartman
2019-09-13 19:39 ` [PATCH 5.2 00/37] 5.2.15-stable review kernelci.org bot
2019-09-14  4:26 ` Naresh Kamboju
2019-09-14  7:43   ` Greg Kroah-Hartman
2019-09-14 14:08 ` Guenter Roeck
2019-09-15 13:34 ` Greg Kroah-Hartman
2019-09-16  9:25 ` Jon Hunter
2019-09-16 10:41   ` Greg Kroah-Hartman

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