[PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target

[Anup Sharma]

syzbot found  UBSAN: shift-out-of-bounds in nci_activate_target [1],
when nci_target->supported_protocols is bigger than UNIT_MAX,
where supported_protocols is unsigned 32-bit interger type.

32 is the maximum allowed for supported_protocols. Added a check
for it. 

[1] UBSAN: shift-out-of-bounds in net/nfc/nci/core.c:912:45
shift exponent 4294967071 is too large for 32-bit type 'int'
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
 nci_activate_target.cold+0x1a/0x1f net/nfc/nci/core.c:912
 nfc_activate_target+0x1f8/0x4c0 net/nfc/core.c:420
 nfc_genl_activate_target+0x1f3/0x290 net/nfc/netlink.c:900
 genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
 genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]

Reported-by: syzbot+0839b78e119aae1fec78@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433

Signed-off-by: anupsharma <anupnewsmail@xxxxxxxxx>
---
 net/nfc/nci/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index fff755dde30d..e9d968bd1cd9 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -908,6 +908,11 @@ static int nci_activate_target(struct nfc_dev *nfc_dev,
 		pr_err("unable to find the selected target\n");
 		return -EINVAL;
 	}
+	
+	if (nci_target->supported_protocols >= 32) {
+		pr_err("Too many supported protocol by the device\n");
+		return -EINVAL;
+	}
 
 	if (!(nci_target->supported_protocols & (1 << protocol))) {
 		pr_err("target does not support the requested protocol 0x%x\n",
-- 
2.34.1