| Message ID | 20230814013352.2771452-1-dongchenchen2@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: xfrm: skip policies marked as dead while reinserting policies | expand |
On Mon, Aug 14, 2023 at 09:33:52AM +0800, Dong Chenchen wrote: > BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 > Read of size 1 at addr ffff8881051f3bf8 by task ip/668 > > CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 > Call Trace: > <TASK> > dump_stack_lvl+0x72/0xa0 > print_report+0xd0/0x620 > kasan_report+0xb6/0xf0 > xfrm_policy_inexact_list_reinsert+0xb6/0x430 > xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 > xfrm_policy_inexact_alloc_chain+0x23f/0x320 > xfrm_policy_inexact_insert+0x6b/0x590 > xfrm_policy_insert+0x3b1/0x480 > xfrm_add_policy+0x23c/0x3c0 > xfrm_user_rcv_msg+0x2d0/0x510 > netlink_rcv_skb+0x10d/0x2d0 > xfrm_netlink_rcv+0x49/0x60 > netlink_unicast+0x3fe/0x540 > netlink_sendmsg+0x528/0x970 > sock_sendmsg+0x14a/0x160 > ____sys_sendmsg+0x4fc/0x580 > ___sys_sendmsg+0xef/0x160 > __sys_sendmsg+0xf7/0x1b0 > do_syscall_64+0x3f/0x90 > entry_SYSCALL_64_after_hwframe+0x73/0xdd > > The root cause is: > > cpu 0 cpu1 > xfrm_dump_policy > xfrm_policy_walk > list_move_tail > xfrm_add_policy > ... ... > xfrm_policy_inexact_list_reinsert > list_for_each_entry_reverse > if (!policy->bydst_reinsert) > //read non-existent policy > xfrm_dump_policy_done > xfrm_policy_walk_done > list_del(&walk->walk.all); > > If dump_one_policy() returns err (triggered by netlink socket), > xfrm_policy_walk() will move walk initialized by socket to list > net->xfrm.policy_all. so this socket becomes visible in the global > policy list. The head *walk can be traversed when users add policies > with different prefixlen and trigger xfrm_policy node merge. > > It can be fixed by skip such "policies" with walk.dead set to 1. But where in the xfrm_dump_policy() flow, these policies are becoming to be walk.dead == 1? Thanks > > Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") > Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") > Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> > --- > net/xfrm/xfrm_policy.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c > index d6b405782b63..5b56faad78e0 100644 > --- a/net/xfrm/xfrm_policy.c > +++ b/net/xfrm/xfrm_policy.c > @@ -848,6 +848,9 @@ static void xfrm_policy_inexact_list_reinsert(struct net *net, > matched_d = 0; > > list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { > + if (policy->walk.dead) > + continue; > + > struct hlist_node *newpos = NULL; > bool matches_s, matches_d; > > -- > 2.25.1 > >
On Mon, Aug 14, 2023 at 04:58:46PM +0800, Dong Chenchen wrote: > On Mon, Aug 14, 2023 at 09:33:52AM +0800, Dong Chenchen wrote: > >> BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 > >> Read of size 1 at addr ffff8881051f3bf8 by task ip/668 > >> > >> CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 > >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 > >> Call Trace: > >> <TASK> > >> dump_stack_lvl+0x72/0xa0 > >> print_report+0xd0/0x620 > >> kasan_report+0xb6/0xf0 > >> xfrm_policy_inexact_list_reinsert+0xb6/0x430 > >> xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 > >> xfrm_policy_inexact_alloc_chain+0x23f/0x320 > >> xfrm_policy_inexact_insert+0x6b/0x590 > >> xfrm_policy_insert+0x3b1/0x480 > >> xfrm_add_policy+0x23c/0x3c0 > >> xfrm_user_rcv_msg+0x2d0/0x510 > >> netlink_rcv_skb+0x10d/0x2d0 > >> xfrm_netlink_rcv+0x49/0x60 > >> netlink_unicast+0x3fe/0x540 > >> netlink_sendmsg+0x528/0x970 > >> sock_sendmsg+0x14a/0x160 > >> ____sys_sendmsg+0x4fc/0x580 > >> ___sys_sendmsg+0xef/0x160 > >> __sys_sendmsg+0xf7/0x1b0 > >> do_syscall_64+0x3f/0x90 > >> entry_SYSCALL_64_after_hwframe+0x73/0xdd > >> > >> The root cause is: > >> > >> cpu 0 cpu1 > >> xfrm_dump_policy > >> xfrm_policy_walk > >> list_move_tail > >> xfrm_add_policy > >> ... ... > >> xfrm_policy_inexact_list_reinsert > >> list_for_each_entry_reverse > >> if (!policy->bydst_reinsert) > >> //read non-existent policy > >> xfrm_dump_policy_done > >> xfrm_policy_walk_done > >> list_del(&walk->walk.all); > >> > >> If dump_one_policy() returns err (triggered by netlink socket), > >> xfrm_policy_walk() will move walk initialized by socket to list > >> net->xfrm.policy_all. so this socket becomes visible in the global > >> policy list. The head *walk can be traversed when users add policies > >> with different prefixlen and trigger xfrm_policy node merge. > >> > >> It can be fixed by skip such "policies" with walk.dead set to 1. > > > >But where in the xfrm_dump_policy() flow, these policies are becoming to > >be walk.dead == 1? > > > >Thanks > > > user will use xfrm_dispatch[XFRM_MSG_GETPOLICY] ops to get xfrm policy. > > .start = xfrm_dump_policy_start > > xfrm_dump_policy_start() will set walk.dead to 1 by call > xfrm_policy_walk_init(). Thanks > > Thanks > >> > >> Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") > >> Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") > >> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> > >> --- > >> net/xfrm/xfrm_policy.c | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c > >> index d6b405782b63..5b56faad78e0 100644 > >> --- a/net/xfrm/xfrm_policy.c > >> +++ b/net/xfrm/xfrm_policy.c > >> @@ -848,6 +848,9 @@ static void xfrm_policy_inexact_list_reinsert(struct net *net, > >> matched_d = 0; > >> > >> list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { > >> + if (policy->walk.dead) > >> + continue; > >> + > >> struct hlist_node *newpos = NULL; > >> bool matches_s, matches_d; > >> > >> -- > >> 2.25.1 > >> > >> >
On Mon, Aug 14, 2023 at 09:33:52AM +0800, Dong Chenchen wrote: > BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 > Read of size 1 at addr ffff8881051f3bf8 by task ip/668 > > CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 > Call Trace: > <TASK> > dump_stack_lvl+0x72/0xa0 > print_report+0xd0/0x620 > kasan_report+0xb6/0xf0 > xfrm_policy_inexact_list_reinsert+0xb6/0x430 > xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 > xfrm_policy_inexact_alloc_chain+0x23f/0x320 > xfrm_policy_inexact_insert+0x6b/0x590 > xfrm_policy_insert+0x3b1/0x480 > xfrm_add_policy+0x23c/0x3c0 > xfrm_user_rcv_msg+0x2d0/0x510 > netlink_rcv_skb+0x10d/0x2d0 > xfrm_netlink_rcv+0x49/0x60 > netlink_unicast+0x3fe/0x540 > netlink_sendmsg+0x528/0x970 > sock_sendmsg+0x14a/0x160 > ____sys_sendmsg+0x4fc/0x580 > ___sys_sendmsg+0xef/0x160 > __sys_sendmsg+0xf7/0x1b0 > do_syscall_64+0x3f/0x90 > entry_SYSCALL_64_after_hwframe+0x73/0xdd > > The root cause is: > > cpu 0 cpu1 > xfrm_dump_policy > xfrm_policy_walk > list_move_tail > xfrm_add_policy > ... ... > xfrm_policy_inexact_list_reinsert > list_for_each_entry_reverse > if (!policy->bydst_reinsert) > //read non-existent policy > xfrm_dump_policy_done > xfrm_policy_walk_done > list_del(&walk->walk.all); > > If dump_one_policy() returns err (triggered by netlink socket), > xfrm_policy_walk() will move walk initialized by socket to list > net->xfrm.policy_all. so this socket becomes visible in the global > policy list. The head *walk can be traversed when users add policies > with different prefixlen and trigger xfrm_policy node merge. > > It can be fixed by skip such "policies" with walk.dead set to 1. > > Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") > Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") > Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> > --- > net/xfrm/xfrm_policy.c | 3 +++ > 1 file changed, 3 insertions(+) > Thanks, Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Dong Chenchen <dongchenchen2@huawei.com> wrote: > BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 > Read of size 1 at addr ffff8881051f3bf8 by task ip/668 > > CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 > Call Trace: > <TASK> > dump_stack_lvl+0x72/0xa0 > print_report+0xd0/0x620 > kasan_report+0xb6/0xf0 > xfrm_policy_inexact_list_reinsert+0xb6/0x430 > xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 > xfrm_policy_inexact_alloc_chain+0x23f/0x320 > xfrm_policy_inexact_insert+0x6b/0x590 > xfrm_policy_insert+0x3b1/0x480 > xfrm_add_policy+0x23c/0x3c0 > xfrm_user_rcv_msg+0x2d0/0x510 > netlink_rcv_skb+0x10d/0x2d0 > xfrm_netlink_rcv+0x49/0x60 > netlink_unicast+0x3fe/0x540 > netlink_sendmsg+0x528/0x970 > sock_sendmsg+0x14a/0x160 > ____sys_sendmsg+0x4fc/0x580 > ___sys_sendmsg+0xef/0x160 > __sys_sendmsg+0xf7/0x1b0 > do_syscall_64+0x3f/0x90 > entry_SYSCALL_64_after_hwframe+0x73/0xdd > > The root cause is: > > cpu 0 cpu1 > xfrm_dump_policy > xfrm_policy_walk > list_move_tail > xfrm_add_policy > ... ... > xfrm_policy_inexact_list_reinsert > list_for_each_entry_reverse > if (!policy->bydst_reinsert) > //read non-existent policy > xfrm_dump_policy_done > xfrm_policy_walk_done > list_del(&walk->walk.all); > > If dump_one_policy() returns err (triggered by netlink socket), > xfrm_policy_walk() will move walk initialized by socket to list > net->xfrm.policy_all. so this socket becomes visible in the global > policy list. The head *walk can be traversed when users add policies > with different prefixlen and trigger xfrm_policy node merge. > > It can be fixed by skip such "policies" with walk.dead set to 1. > > Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") > Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") > Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> > --- > net/xfrm/xfrm_policy.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c > index d6b405782b63..5b56faad78e0 100644 > --- a/net/xfrm/xfrm_policy.c > +++ b/net/xfrm/xfrm_policy.c > @@ -848,6 +848,9 @@ static void xfrm_policy_inexact_list_reinsert(struct net *net, > matched_d = 0; > > list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { > + if (policy->walk.dead) > + continue; > + Looks like we have other places that might trigger a splat, e.g.: 1816 int xfrm_policy_flush(struct net *net, u8 type, bool task_valid) .. 1827 again: 1828 list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) { 1829 dir = xfrm_policy_id2dir(pol->index); 1830 if (pol->walk.dead || 1831 dir >= XFRM_POLICY_MAX || 'walker' has no pol->index, so I suspect this would trigger a kasan splat as well, this needs to check walk.dead before access to pol->index.
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index d6b405782b63..5b56faad78e0 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -848,6 +848,9 @@ static void xfrm_policy_inexact_list_reinsert(struct net *net, matched_d = 0; list_for_each_entry_reverse(policy, &net->xfrm.policy_all, walk.all) { + if (policy->walk.dead) + continue; + struct hlist_node *newpos = NULL; bool matches_s, matches_d;
BUG: KASAN: slab-use-after-free in xfrm_policy_inexact_list_reinsert+0xb6/0x430 Read of size 1 at addr ffff8881051f3bf8 by task ip/668 CPU: 2 PID: 668 Comm: ip Not tainted 6.5.0-rc5-00182-g25aa0bebba72-dirty #64 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x72/0xa0 print_report+0xd0/0x620 kasan_report+0xb6/0xf0 xfrm_policy_inexact_list_reinsert+0xb6/0x430 xfrm_policy_inexact_insert_node.constprop.0+0x537/0x800 xfrm_policy_inexact_alloc_chain+0x23f/0x320 xfrm_policy_inexact_insert+0x6b/0x590 xfrm_policy_insert+0x3b1/0x480 xfrm_add_policy+0x23c/0x3c0 xfrm_user_rcv_msg+0x2d0/0x510 netlink_rcv_skb+0x10d/0x2d0 xfrm_netlink_rcv+0x49/0x60 netlink_unicast+0x3fe/0x540 netlink_sendmsg+0x528/0x970 sock_sendmsg+0x14a/0x160 ____sys_sendmsg+0x4fc/0x580 ___sys_sendmsg+0xef/0x160 __sys_sendmsg+0xf7/0x1b0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x73/0xdd The root cause is: cpu 0 cpu1 xfrm_dump_policy xfrm_policy_walk list_move_tail xfrm_add_policy ... ... xfrm_policy_inexact_list_reinsert list_for_each_entry_reverse if (!policy->bydst_reinsert) //read non-existent policy xfrm_dump_policy_done xfrm_policy_walk_done list_del(&walk->walk.all); If dump_one_policy() returns err (triggered by netlink socket), xfrm_policy_walk() will move walk initialized by socket to list net->xfrm.policy_all. so this socket becomes visible in the global policy list. The head *walk can be traversed when users add policies with different prefixlen and trigger xfrm_policy node merge. It can be fixed by skip such "policies" with walk.dead set to 1. Fixes: 9cf545ebd591 ("xfrm: policy: store inexact policies in a tree ordered by destination address") Fixes: 12a169e7d8f4 ("ipsec: Put dumpers on the dump list") Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/xfrm/xfrm_policy.c | 3 +++ 1 file changed, 3 insertions(+)