CVE-2024-56663

In the Linux kernel, the following vulnerability has been resolved:

wifi: nl80211: fix NL80211_ATTR_MLO_LINK_ID off-by-one

Since the netlink attribute range validation provides inclusive

checking, the *max* of attribute NL80211_ATTR_MLO_LINK_ID should be

IEEE80211_MLD_MAX_NUM_LINKS - 1 otherwise causing an off-by-one.

One crash stack for demonstration:

==================================================================

BUG: KASAN: wild-memory-access in ieee80211_tx_control_port+0x3b6/0xca0 net/mac80211/tx.c:5939

Read of size 6 at addr 001102080000000c by task fuzzer.386/9508

CPU: 1 PID: 9508 Comm: syz.1.386 Not tainted 6.1.70 #2

Call Trace:

<TASK>

__dump_stack lib/dump_stack.c:88 [inline]

dump_stack_lvl+0x177/0x231 lib/dump_stack.c:106

print_report+0xe0/0x750 mm/kasan/report.c:398

kasan_report+0x139/0x170 mm/kasan/report.c:495

kasan_check_range+0x287/0x290 mm/kasan/generic.c:189

memcpy+0x25/0x60 mm/kasan/shadow.c:65

ieee80211_tx_control_port+0x3b6/0xca0 net/mac80211/tx.c:5939

rdev_tx_control_port net/wireless/rdev-ops.h:761 [inline]

nl80211_tx_control_port+0x7b3/0xc40 net/wireless/nl80211.c:15453

genl_family_rcv_msg_doit+0x22e/0x320 net/netlink/genetlink.c:756

genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]

genl_rcv_msg+0x539/0x740 net/netlink/genetlink.c:850

netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2508

genl_rcv+0x24/0x40 net/netlink/genetlink.c:861

netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]

netlink_unicast+0x74b/0x8c0 net/netlink/af_netlink.c:1352

netlink_sendmsg+0x882/0xb90 net/netlink/af_netlink.c:1874

sock_sendmsg_nosec net/socket.c:716 [inline]

__sock_sendmsg net/socket.c:728 [inline]

____sys_sendmsg+0x5cc/0x8f0 net/socket.c:2499

___sys_sendmsg+0x21c/0x290 net/socket.c:2553

__sys_sendmsg net/socket.c:2582 [inline]

__do_sys_sendmsg net/socket.c:2591 [inline]

__se_sys_sendmsg+0x19e/0x270 net/socket.c:2589

do_syscall_x64 arch/x86/entry/common.c:51 [inline]

do_syscall_64+0x45/0x90 arch/x86/entry/common.c:81

entry_SYSCALL_64_after_hwframe+0x63/0xcd

Update the policy to ensure correct validation.