From 799acb9347915bfe4eac0ff2345b468f0a1ca207 Mon Sep 17 00:00:00 2001
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date: Fri, 28 May 2021 11:45:02 -0700
Subject: [PATCH] Bluetooth: mgmt: Fix slab-out-of-bounds in tlv_data_is_valid
Git-commit: 799acb9347915bfe4eac0ff2345b468f0a1ca207
Patch-mainline: v5.14-rc1
References: git-fixes
This fixes parsing of LTV entries when the length is 0.
Found with:
tools/mgmt-tester -s "Add Advertising - Success (ScRsp only)"
Add Advertising - Success (ScRsp only) - run
Sending Add Advertising (0x003e)
Test condition added, total 1
[ 11.004577] ==================================================================
[ 11.005292] BUG: KASAN: slab-out-of-bounds in tlv_data_is_valid+0x87/0xe0
[ 11.005984] Read of size 1 at addr ffff888002c695b0 by task mgmt-tester/87
[ 11.006711]
[ 11.007176]
[ 11.007429] Allocated by task 87:
[ 11.008151]
[ 11.008438] The buggy address belongs to the object at ffff888002c69580
[ 11.008438] which belongs to the cache kmalloc-64 of size 64
[ 11.010526] The buggy address is located 48 bytes inside of
[ 11.010526] 64-byte region [ffff888002c69580, ffff888002c695c0)
[ 11.012423] The buggy address belongs to the page:
[ 11.013291]
[ 11.013544] Memory state around the buggy address:
[ 11.014359] ffff888002c69480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 11.015453] ffff888002c69500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 11.016232] >ffff888002c69580: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
[ 11.017010] ^
[ 11.017547] ffff888002c69600: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
[ 11.018296] ffff888002c69680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 11.019116] ==================================================================
Fixes: 2bb36870e8cb2 ("Bluetooth: Unify advertising instance flags check")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/bluetooth/mgmt.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 5616e8afb22e..896f0c482912 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -7590,6 +7590,9 @@ static bool tlv_data_is_valid(struct hci_dev *hdev, u32 adv_flags, u8 *data,
for (i = 0, cur_len = 0; i < len; i += (cur_len + 1)) {
cur_len = data[i];
+ if (!cur_len)
+ continue;
+
if (data[i + 1] == EIR_FLAGS &&
(!is_adv_data || flags_managed(adv_flags)))
return false;
--
2.26.2