Re: [syzbot] INFO: task hung in hci_req_sync

[Pavel Skripkin <paskripkin@gmail.com>]

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On 8/17/21 12:01 AM, syzbot wrote:
> Hello,
> 
> syzbot tried to test the proposed patch but the build/boot failed:
> 
> net/bluetooth/hci_core.c:1346:18: error: 'HCI_MAX_TIMEOUT' undeclared (first use in this function); did you mean 'HCI_CMD_TIMEOUT'?
> 
> 
> Tested on:
> 
> commit:         a2824f19 Merge tag 'mtd/fixes-for-5.14-rc7' of git://g..
> git tree:       upstream
> dashboard link: https://syzkaller.appspot.com/bug?extid=be2baed593ea56c6a84c
> compiler:
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=145874a6300000
> 


Woooooops, I forgot to build-test after define rename.

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master




With regards,
Pavel Skripkin

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From b03640e820c7cd3d577e3e472a61a9a7e64a4305 Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Mon, 16 Aug 2021 22:52:29 +0300
Subject: [PATCH] Bluetooth: add timeout sanity check to hci_inquiry

/* ... */

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 include/net/bluetooth/hci_sock.h | 1 +
 net/bluetooth/hci_core.c         | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/net/bluetooth/hci_sock.h b/include/net/bluetooth/hci_sock.h
index 9949870f7d78..1cd63d4da00b 100644
--- a/include/net/bluetooth/hci_sock.h
+++ b/include/net/bluetooth/hci_sock.h
@@ -168,6 +168,7 @@ struct hci_inquiry_req {
 	__u16 dev_id;
 	__u16 flags;
 	__u8  lap[3];
+#define HCI_INQUIRY_MAX_TIMEOUT		30
 	__u8  length;
 	__u8  num_rsp;
 };
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e1a545c8a69f..104babf67351 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1343,6 +1343,11 @@ int hci_inquiry(void __user *arg)
 		goto done;
 	}
 
+	if (ir.length > HCI_INQUIRY_MAX_TIMEOUT) {
+		err = -EINVAL;
+		goto done;
+	}
+
 	hci_dev_lock(hdev);
 	if (inquiry_cache_age(hdev) > INQUIRY_CACHE_AGE_MAX ||
 	    inquiry_cache_empty(hdev) || ir.flags & IREQ_CACHE_FLUSH) {
-- 
2.32.0