| Message ID | 20231011163140.work.317-kees@kernel.org |
|---|---|
| State | Accepted |
| Commit | cb3871b1cd135a6662b732fbc6b3db4afcdb4a64 |
| Headers | show |
| Series | Bluetooth: hci_sock: Correctly bounds check and pad HCI_MON_NEW_INDEX name | expand |
diff --git a/include/net/bluetooth/hci_mon.h b/include/net/bluetooth/hci_mon.h index 2d5fcda1bcd0..082f89531b88 100644 --- a/include/net/bluetooth/hci_mon.h +++ b/include/net/bluetooth/hci_mon.h @@ -56,7 +56,7 @@ struct hci_mon_new_index { __u8 type; __u8 bus; bdaddr_t bdaddr; - char name[8]; + char name[8] __nonstring; } __packed; #define HCI_MON_NEW_INDEX_SIZE 16 diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index 72abe54c45dd..3e7cd330d731 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -488,7 +488,8 @@ static struct sk_buff *create_monitor_event(struct hci_dev *hdev, int event) ni->type = hdev->dev_type; ni->bus = hdev->bus; bacpy(&ni->bdaddr, &hdev->bdaddr); - memcpy(ni->name, hdev->name, strlen(hdev->name)); + memcpy_and_pad(ni->name, sizeof(ni->name), hdev->name, + strnlen(hdev->name, sizeof(ni->name)), '\0'); opcode = cpu_to_le16(HCI_MON_NEW_INDEX); break;
The code pattern of memcpy(dst, src, strlen(src)) is almost always wrong. In this case it is wrong because it leaves memory uninitialized if it is less than sizeof(ni->name), and overflows ni->name when longer. Normally strtomem_pad() could be used here, but since ni->name is a trailing array in struct hci_mon_new_index, compilers that don't support -fstrict-flex-arrays=3 can't tell how large this array is via __builtin_object_size(). Instead, open-code the helper and use sizeof() since it will work correctly. Additionally mark ni->name as __nonstring since it appears to not be a %NUL terminated C string. Cc: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Cc: Edward AD <twuufnxlz@gmail.com> Cc: Marcel Holtmann <marcel@holtmann.org> Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: linux-bluetooth@vger.kernel.org Cc: netdev@vger.kernel.org Fixes: 78480de55a96 ("Bluetooth: hci_sock: fix slab oob read in create_monitor_event") Link: https://lore.kernel.org/lkml/202310110908.F2639D3276@keescook/ Signed-off-by: Kees Cook <keescook@chromium.org> --- include/net/bluetooth/hci_mon.h | 2 +- net/bluetooth/hci_sock.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)