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 and add constant to
hsi_sock.h to inform userspace, that hci_inquiry_req::length field has
maximum possible value.
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
---
Hi, Bluetooth maintainers/reviewers!
I believe, 60 seconds will be more than enough for inquiry request. I've
searched for examples on the internet and maximum ir.length I found was
8. Maybe, we have users, which need more than 60 seconds... I look forward
to receiving your views on this value.
---
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
