From: Pavel Skripkin paskripkin@gmail.com
stable inclusion from linux-4.19.207 commit c52204af399ac67db9eac43aff2d14a4df616bed
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[ Upstream commit f41a4b2b5eb7872109723dab8ae1603bdd9d9ec1 ]
Syzbot hit "task hung" bug in hci_req_sync(). The problem was in unreasonable huge inquiry timeout passed from userspace. Fix it by adding sanity check for timeout value to hci_inquiry().
Since hci_inquiry() is the only user of hci_req_sync() with user controlled timeout value, it makes sense to check timeout value in hci_inquiry() and don't touch hci_req_sync().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin paskripkin@gmail.com Signed-off-by: Marcel Holtmann marcel@holtmann.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/bluetooth/hci_core.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index ec6150564f593..26acacb2fa95f 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -1296,6 +1296,12 @@ int hci_inquiry(void __user *arg) goto done; }
+ /* Restrict maximum inquiry length to 60 seconds */ + if (ir.length > 60) { + 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) {