From: Zekun Shen <bruceshenzk@xxxxxxxxx> [ Upstream commit f1cb3476e48b60c450ec3a1d7da0805bffc6e43a ] rsi_get_* functions rely on an offset variable from usb input. The size of usb input is RSI_MAX_RX_USB_PKT_SIZE(3000), while 2-byte offset can be up to 0xFFFF. Thus a large offset can cause out-of-bounds read. The patch adds a bound checking condition when rcv_pkt_len is 0, indicating it's USB. It's unclear whether this is triggerable from other type of bus. The following check might help in that case. offset > rcv_pkt_len - FRAME_DESC_SZ The bug is trigerrable with conpromised/malfunctioning USB devices. I tested the patch with the crashing input and got no more bug report. Attached is the KASAN report from fuzzing. BUG: KASAN: slab-out-of-bounds in rsi_read_pkt+0x42e/0x500 [rsi_91x] Read of size 2 at addr ffff888019439fdb by task RX-Thread/227 CPU: 0 PID: 227 Comm: RX-Thread Not tainted 5.6.0 #66 Call Trace: dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? rsi_read_pkt+0x42e/0x500 [rsi_91x] ? rsi_read_pkt+0x42e/0x500 [rsi_91x] __kasan_report.cold+0x37/0x7c ? rsi_read_pkt+0x42e/0x500 [rsi_91x] kasan_report+0xe/0x20 rsi_read_pkt+0x42e/0x500 [rsi_91x] rsi_usb_rx_thread+0x1b1/0x2fc [rsi_usb] ? rsi_probe+0x16a0/0x16a0 [rsi_usb] ? _raw_spin_lock_irqsave+0x7b/0xd0 ? _raw_spin_trylock_bh+0x120/0x120 ? __wake_up_common+0x10b/0x520 ? rsi_probe+0x16a0/0x16a0 [rsi_usb] kthread+0x2b5/0x3b0 ? kthread_create_on_node+0xd0/0xd0 ret_from_fork+0x22/0x40 Reported-by: Brendan Dolan-Gavitt <brendandg@xxxxxxx> Signed-off-by: Zekun Shen <bruceshenzk@xxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/YXxXS4wgu2OsmlVv@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/wireless/rsi/rsi_91x_main.c | 4 ++++ drivers/net/wireless/rsi/rsi_91x_usb.c | 1 - drivers/net/wireless/rsi/rsi_usb.h | 2 ++ 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/rsi/rsi_91x_main.c b/drivers/net/wireless/rsi/rsi_91x_main.c index 8c638cfeac52f..fe8aed58ac088 100644 --- a/drivers/net/wireless/rsi/rsi_91x_main.c +++ b/drivers/net/wireless/rsi/rsi_91x_main.c @@ -23,6 +23,7 @@ #include "rsi_common.h" #include "rsi_coex.h" #include "rsi_hal.h" +#include "rsi_usb.h" u32 rsi_zone_enabled = /* INFO_ZONE | INIT_ZONE | @@ -168,6 +169,9 @@ int rsi_read_pkt(struct rsi_common *common, u8 *rx_pkt, s32 rcv_pkt_len) frame_desc = &rx_pkt[index]; actual_length = *(u16 *)&frame_desc[0]; offset = *(u16 *)&frame_desc[2]; + if (!rcv_pkt_len && offset > + RSI_MAX_RX_USB_PKT_SIZE - FRAME_DESC_SZ) + goto fail; queueno = rsi_get_queueno(frame_desc, offset); length = rsi_get_length(frame_desc, offset); diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c b/drivers/net/wireless/rsi/rsi_91x_usb.c index 7f34148c7dfe5..11388a1469621 100644 --- a/drivers/net/wireless/rsi/rsi_91x_usb.c +++ b/drivers/net/wireless/rsi/rsi_91x_usb.c @@ -328,7 +328,6 @@ static int rsi_rx_urb_submit(struct rsi_hw *adapter, u8 ep_num, gfp_t mem_flags) struct sk_buff *skb; u8 dword_align_bytes = 0; -#define RSI_MAX_RX_USB_PKT_SIZE 3000 skb = dev_alloc_skb(RSI_MAX_RX_USB_PKT_SIZE); if (!skb) return -ENOMEM; diff --git a/drivers/net/wireless/rsi/rsi_usb.h b/drivers/net/wireless/rsi/rsi_usb.h index 8702f434b5699..ad88f8c70a351 100644 --- a/drivers/net/wireless/rsi/rsi_usb.h +++ b/drivers/net/wireless/rsi/rsi_usb.h @@ -44,6 +44,8 @@ #define RSI_USB_BUF_SIZE 4096 #define RSI_USB_CTRL_BUF_SIZE 0x04 +#define RSI_MAX_RX_USB_PKT_SIZE 3000 + struct rx_usb_ctrl_block { u8 *data; struct urb *rx_urb; -- 2.34.1
