* [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets
@ 2021-04-28 13:23 Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 1/2] openvswitch: " Davide Caratti
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Davide Caratti @ 2021-04-28 13:23 UTC (permalink / raw)
To: Jakub Kicinski, David S. Miller, netdev
- patch 1/2 fixes openvswitch IPv4 fragmentation, that does a stack OOB
read after commit d52e5a7e7ca4 ("ipv4: lock mtu in fnhe when received
PMTU < net.ipv4.route.min_pmt")
- patch 2/2 fixes the same issue in TC 'sch_frag' code
Davide Caratti (2):
openvswitch: fix stack OOB read while fragmenting IPv4 packets
net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
net/openvswitch/actions.c | 8 ++++----
net/sched/sch_frag.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)
--
2.30.2
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH net resend 1/2] openvswitch: fix stack OOB read while fragmenting IPv4 packets
2021-04-28 13:23 [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets Davide Caratti
@ 2021-04-28 13:23 ` Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 2/2] net/sched: sch_frag: " Davide Caratti
2021-04-29 22:40 ` [PATCH net resend 0/2] " patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Davide Caratti @ 2021-04-28 13:23 UTC (permalink / raw)
To: Pravin B Shelar, David S. Miller, Jakub Kicinski,
Sabrina Dubroca, Stefano Brivio, netdev
Cc: dev, echaudro
running openvswitch on kernels built with KASAN, it's possible to see the
following splat while testing fragmentation of IPv4 packets:
BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60
Read of size 1 at addr ffff888112fc713c by task handler2/1367
CPU: 0 PID: 1367 Comm: handler2 Not tainted 5.12.0-rc6+ #418
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
Call Trace:
dump_stack+0x92/0xc1
print_address_description.constprop.7+0x1a/0x150
kasan_report.cold.13+0x7f/0x111
ip_do_fragment+0x1b03/0x1f60
ovs_fragment+0x5bf/0x840 [openvswitch]
do_execute_actions+0x1bd5/0x2400 [openvswitch]
ovs_execute_actions+0xc8/0x3d0 [openvswitch]
ovs_packet_cmd_execute+0xa39/0x1150 [openvswitch]
genl_family_rcv_msg_doit.isra.15+0x227/0x2d0
genl_rcv_msg+0x287/0x490
netlink_rcv_skb+0x120/0x380
genl_rcv+0x24/0x40
netlink_unicast+0x439/0x630
netlink_sendmsg+0x719/0xbf0
sock_sendmsg+0xe2/0x110
____sys_sendmsg+0x5ba/0x890
___sys_sendmsg+0xe9/0x160
__sys_sendmsg+0xd3/0x170
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f957079db07
Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 eb ec ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 24 ed ff ff 48
RSP: 002b:00007f956ce35a50 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f957079db07
RDX: 0000000000000000 RSI: 00007f956ce35ae0 RDI: 0000000000000019
RBP: 00007f956ce35ae0 R08: 0000000000000000 R09: 00007f9558006730
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f956ce37308 R14: 00007f956ce35f80 R15: 00007f956ce35ae0
The buggy address belongs to the page:
page:00000000af2a1d93 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112fc7
flags: 0x17ffffc0000000()
raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
addr ffff888112fc713c is located in stack of task handler2/1367 at offset 180 in frame:
ovs_fragment+0x0/0x840 [openvswitch]
this frame has 2 objects:
[32, 144) 'ovs_dst'
[192, 424) 'ovs_rt'
Memory state around the buggy address:
ffff888112fc7000: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888112fc7080: 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00
>ffff888112fc7100: 00 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00
^
ffff888112fc7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888112fc7200: 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00
for IPv4 packets, ovs_fragment() uses a temporary struct dst_entry. Then,
in the following call graph:
ip_do_fragment()
ip_skb_dst_mtu()
ip_dst_mtu_maybe_forward()
ip_mtu_locked()
the pointer to struct dst_entry is used as pointer to struct rtable: this
turns the access to struct members like rt_mtu_locked into an OOB read in
the stack. Fix this changing the temporary variable used for IPv4 packets
in ovs_fragment(), similarly to what is done for IPv6 few lines below.
Fixes: d52e5a7e7ca4 ("ipv4: lock mtu in fnhe when received PMTU < net.ipv4.route.min_pmt")
Cc: <stable@vger.kernel.org>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
net/openvswitch/actions.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 92a0b67b2728..77d924ab8cdb 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -827,17 +827,17 @@ static void ovs_fragment(struct net *net, struct vport *vport,
}
if (key->eth.type == htons(ETH_P_IP)) {
- struct dst_entry ovs_dst;
+ struct rtable ovs_rt = { 0 };
unsigned long orig_dst;
prepare_frag(vport, skb, orig_network_offset,
ovs_key_mac_proto(key));
- dst_init(&ovs_dst, &ovs_dst_ops, NULL, 1,
+ dst_init(&ovs_rt.dst, &ovs_dst_ops, NULL, 1,
DST_OBSOLETE_NONE, DST_NOCOUNT);
- ovs_dst.dev = vport->dev;
+ ovs_rt.dst.dev = vport->dev;
orig_dst = skb->_skb_refdst;
- skb_dst_set_noref(skb, &ovs_dst);
+ skb_dst_set_noref(skb, &ovs_rt.dst);
IPCB(skb)->frag_max_size = mru;
ip_do_fragment(net, skb->sk, skb, ovs_vport_output);
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH net resend 2/2] net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
2021-04-28 13:23 [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 1/2] openvswitch: " Davide Caratti
@ 2021-04-28 13:23 ` Davide Caratti
2021-04-29 22:40 ` [PATCH net resend 0/2] " patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Davide Caratti @ 2021-04-28 13:23 UTC (permalink / raw)
To: Jamal Hadi Salim, Cong Wang, Jiri Pirko, David S. Miller,
Jakub Kicinski, wenxu, netdev
Cc: Marcelo Ricardo Leitner, shuali
when 'act_mirred' tries to fragment IPv4 packets that had been previously
re-assembled using 'act_ct', splats like the following can be observed on
kernels built with KASAN:
BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60
Read of size 1 at addr ffff888147009574 by task ping/947
CPU: 0 PID: 947 Comm: ping Not tainted 5.12.0-rc6+ #418
Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014
Call Trace:
<IRQ>
dump_stack+0x92/0xc1
print_address_description.constprop.7+0x1a/0x150
kasan_report.cold.13+0x7f/0x111
ip_do_fragment+0x1b03/0x1f60
sch_fragment+0x4bf/0xe40
tcf_mirred_act+0xc3d/0x11a0 [act_mirred]
tcf_action_exec+0x104/0x3e0
fl_classify+0x49a/0x5e0 [cls_flower]
tcf_classify_ingress+0x18a/0x820
__netif_receive_skb_core+0xae7/0x3340
__netif_receive_skb_one_core+0xb6/0x1b0
process_backlog+0x1ef/0x6c0
__napi_poll+0xaa/0x500
net_rx_action+0x702/0xac0
__do_softirq+0x1e4/0x97f
do_softirq+0x71/0x90
</IRQ>
__local_bh_enable_ip+0xdb/0xf0
ip_finish_output2+0x760/0x2120
ip_do_fragment+0x15a5/0x1f60
__ip_finish_output+0x4c2/0xea0
ip_output+0x1ca/0x4d0
ip_send_skb+0x37/0xa0
raw_sendmsg+0x1c4b/0x2d00
sock_sendmsg+0xdb/0x110
__sys_sendto+0x1d7/0x2b0
__x64_sys_sendto+0xdd/0x1b0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f82e13853eb
Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89
RSP: 002b:00007ffe01fad888 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00005571aac13700 RCX: 00007f82e13853eb
RDX: 0000000000002330 RSI: 00005571aac13700 RDI: 0000000000000003
RBP: 0000000000002330 R08: 00005571aac10500 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe01faefb0
R13: 00007ffe01fad890 R14: 00007ffe01fad980 R15: 00005571aac0f0a0
The buggy address belongs to the page:
page:000000001dff2e03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147009
flags: 0x17ffffc0001000(reserved)
raw: 0017ffffc0001000 ffffea00051c0248 ffffea00051c0248 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888147009400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888147009480: f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00 00
>ffff888147009500: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2
^
ffff888147009580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888147009600: 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2
for IPv4 packets, sch_fragment() uses a temporary struct dst_entry. Then,
in the following call graph:
ip_do_fragment()
ip_skb_dst_mtu()
ip_dst_mtu_maybe_forward()
ip_mtu_locked()
the pointer to struct dst_entry is used as pointer to struct rtable: this
turns the access to struct members like rt_mtu_locked into an OOB read in
the stack. Fix this changing the temporary variable used for IPv4 packets
in sch_fragment(), similarly to what is done for IPv6 few lines below.
Fixes: c129412f74e9 ("net/sched: sch_frag: add generic packet fragment support.")
Cc: <stable@vger.kernel.org> # 5.11
Reported-by: Shuang Li <shuali@redhat.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
net/sched/sch_frag.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/sched/sch_frag.c b/net/sched/sch_frag.c
index e1e77d3fb6c0..8c06381391d6 100644
--- a/net/sched/sch_frag.c
+++ b/net/sched/sch_frag.c
@@ -90,16 +90,16 @@ static int sch_fragment(struct net *net, struct sk_buff *skb,
}
if (skb_protocol(skb, true) == htons(ETH_P_IP)) {
- struct dst_entry sch_frag_dst;
+ struct rtable sch_frag_rt = { 0 };
unsigned long orig_dst;
sch_frag_prepare_frag(skb, xmit);
- dst_init(&sch_frag_dst, &sch_frag_dst_ops, NULL, 1,
+ dst_init(&sch_frag_rt.dst, &sch_frag_dst_ops, NULL, 1,
DST_OBSOLETE_NONE, DST_NOCOUNT);
- sch_frag_dst.dev = skb->dev;
+ sch_frag_rt.dst.dev = skb->dev;
orig_dst = skb->_skb_refdst;
- skb_dst_set_noref(skb, &sch_frag_dst);
+ skb_dst_set_noref(skb, &sch_frag_rt.dst);
IPCB(skb)->frag_max_size = mru;
ret = ip_do_fragment(net, skb->sk, skb, sch_frag_xmit);
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets
2021-04-28 13:23 [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 1/2] openvswitch: " Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 2/2] net/sched: sch_frag: " Davide Caratti
@ 2021-04-29 22:40 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-04-29 22:40 UTC (permalink / raw)
To: Davide Caratti; +Cc: kuba, davem, netdev
Hello:
This series was applied to netdev/net.git (refs/heads/master):
On Wed, 28 Apr 2021 15:23:00 +0200 you wrote:
> - patch 1/2 fixes openvswitch IPv4 fragmentation, that does a stack OOB
> read after commit d52e5a7e7ca4 ("ipv4: lock mtu in fnhe when received
> PMTU < net.ipv4.route.min_pmt")
> - patch 2/2 fixes the same issue in TC 'sch_frag' code
>
> Davide Caratti (2):
> openvswitch: fix stack OOB read while fragmenting IPv4 packets
> net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
>
> [...]
Here is the summary with links:
- [net,resend,1/2] openvswitch: fix stack OOB read while fragmenting IPv4 packets
https://git.kernel.org/netdev/net/c/7c0ea5930c1c
- [net,resend,2/2] net/sched: sch_frag: fix stack OOB read while fragmenting IPv4 packets
https://git.kernel.org/netdev/net/c/31fe34a0118e
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-28 13:23 [PATCH net resend 0/2] fix stack OOB read while fragmenting IPv4 packets Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 1/2] openvswitch: " Davide Caratti
2021-04-28 13:23 ` [PATCH net resend 2/2] net/sched: sch_frag: " Davide Caratti
2021-04-29 22:40 ` [PATCH net resend 0/2] " patchwork-bot+netdevbpf
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