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

Anup Sharma
2023-04-19T01:16:33Z

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@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433

Signed-off-by: anupsharma <anupnewsmail@gmail.com>
---
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