From 4d50e50045aa46d9f3e578ed2edea9bd0a123d24 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 26 Jul 2023 14:58:15 +0000 Subject: net: flower: fix stack-out-of-bounds in fl_set_key_cfm() Typical misuse of nla_parse_nested(array, XXX_MAX, ...); array must be declared as struct nlattr *array[XXX_MAX + 1]; v2: Based on feedbacks from Ido Schimmel and Zahari Doychev, I also changed TCA_FLOWER_KEY_CFM_OPT_MAX and cfm_opt_policy definitions. syzbot reported: BUG: KASAN: stack-out-of-bounds in __nla_validate_parse+0x136/0x2bd0 lib/nlattr.c:588 Write of size 32 at addr ffffc90003a0ee20 by task syz-executor296/5014 CPU: 0 PID: 5014 Comm: syz-executor296 Not tainted 6.5.0-rc2-syzkaller-00307-gd192f5382581 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0x163/0x540 mm/kasan/report.c:475 kasan_report+0x175/0x1b0 mm/kasan/report.c:588 kasan_check_range+0x27e/0x290 mm/kasan/generic.c:187 __asan_memset+0x23/0x40 mm/kasan/shadow.c:84 __nla_validate_parse+0x136/0x2bd0 lib/nlattr.c:588 __nla_parse+0x40/0x50 lib/nlattr.c:700 nla_parse_nested include/net/netlink.h:1262 [inline] fl_set_key_cfm+0x1e3/0x440 net/sched/cls_flower.c:1718 fl_set_key+0x2168/0x6620 net/sched/cls_flower.c:1884 fl_tmplt_create+0x1fe/0x510 net/sched/cls_flower.c:2666 tc_chain_tmplt_add net/sched/cls_api.c:2959 [inline] tc_ctl_chain+0x131d/0x1ac0 net/sched/cls_api.c:3068 rtnetlink_rcv_msg+0x82b/0xf50 net/core/rtnetlink.c:6424 netlink_rcv_skb+0x1df/0x430 net/netlink/af_netlink.c:2549 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x7c3/0x990 net/netlink/af_netlink.c:1365 netlink_sendmsg+0xa2a/0xd60 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg net/socket.c:748 [inline] ____sys_sendmsg+0x592/0x890 net/socket.c:2494 ___sys_sendmsg net/socket.c:2548 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2577 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f54c6150759 Code: 48 83 c4 28 c3 e8 d7 19 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe06c30578 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f54c619902d RCX: 00007f54c6150759 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003 RBP: 00007ffe06c30590 R08: 0000000000000000 R09: 00007ffe06c305f0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f54c61c35f0 R13: 00007ffe06c30778 R14: 0000000000000001 R15: 0000000000000001 The buggy address belongs to stack of task syz-executor296/5014 and is located at offset 32 in frame: fl_set_key_cfm+0x0/0x440 net/sched/cls_flower.c:374 This frame has 1 object: [32, 56) 'nla_cfm_opt' The buggy address belongs to the virtual mapping at [ffffc90003a08000, ffffc90003a11000) created by: copy_process+0x5c8/0x4290 kernel/fork.c:2330 Fixes: 7cfffd5fed3e ("net: flower: add support for matching cfm fields") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Simon Horman Reviewed-by: Ido Schimmel Reviewed-by: Zahari Doychev Link: https://lore.kernel.org/r/20230726145815.943910-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/sched/cls_flower.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/sched/cls_flower.c') diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 8da9d039d964..9f0711da9c95 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -776,7 +776,8 @@ mpls_stack_entry_policy[TCA_FLOWER_KEY_MPLS_OPT_LSE_MAX + 1] = { [TCA_FLOWER_KEY_MPLS_OPT_LSE_LABEL] = { .type = NLA_U32 }, }; -static const struct nla_policy cfm_opt_policy[TCA_FLOWER_KEY_CFM_OPT_MAX] = { +static const struct nla_policy +cfm_opt_policy[TCA_FLOWER_KEY_CFM_OPT_MAX + 1] = { [TCA_FLOWER_KEY_CFM_MD_LEVEL] = NLA_POLICY_MAX(NLA_U8, FLOW_DIS_CFM_MDL_MAX), [TCA_FLOWER_KEY_CFM_OPCODE] = { .type = NLA_U8 }, @@ -1709,7 +1710,7 @@ static int fl_set_key_cfm(struct nlattr **tb, struct fl_flow_key *mask, struct netlink_ext_ack *extack) { - struct nlattr *nla_cfm_opt[TCA_FLOWER_KEY_CFM_OPT_MAX]; + struct nlattr *nla_cfm_opt[TCA_FLOWER_KEY_CFM_OPT_MAX + 1]; int err; if (!tb[TCA_FLOWER_KEY_CFM]) -- cgit