6.6-stable review patch. If anyone has any objections, please let me know.
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From: Lin Ma linma@zju.edu.cn
[ Upstream commit 2e3dbf938656986cce73ac4083500d0bcfbffe24 ]
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.
Fixes: 7b0a0e3c3a88 ("wifi: cfg80211: do some rework towards MLO link APIs") Signed-off-by: Lin Ma linma@zju.edu.cn Suggested-by: Cengiz Can cengiz.can@canonical.com Link: https://patch.msgid.link/20241130170526.96698-1-linma@zju.edu.cn Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/wireless/nl80211.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 797907303669..5b9f39d93b04 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -811,7 +811,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_MLO_LINKS] = NLA_POLICY_NESTED_ARRAY(nl80211_policy), [NL80211_ATTR_MLO_LINK_ID] = - NLA_POLICY_RANGE(NLA_U8, 0, IEEE80211_MLD_MAX_NUM_LINKS), + NLA_POLICY_RANGE(NLA_U8, 0, IEEE80211_MLD_MAX_NUM_LINKS - 1), [NL80211_ATTR_MLD_ADDR] = NLA_POLICY_EXACT_LEN(ETH_ALEN), [NL80211_ATTR_MLO_SUPPORT] = { .type = NLA_FLAG }, [NL80211_ATTR_MAX_NUM_AKM_SUITES] = { .type = NLA_REJECT },