* [PATCH v5.15 1/2] net/ipv6: annotate data-races around cnf.disable_ipv6
2024-07-09 10:19 [PATCH v5.15 0/2] Fix for CVE-2024-36901 Ashwin Kamat
@ 2024-07-09 10:19 ` Ashwin Kamat
2024-07-09 10:19 ` [PATCH v5.15 2/2] net/ipv6: prevent NULL dereference in ip6_output() Ashwin Kamat
2024-07-12 21:19 ` [PATCH v5.15 0/2] Fix for CVE-2024-36901 Florian Fainelli
2 siblings, 0 replies; 4+ messages in thread
From: Ashwin Kamat @ 2024-07-09 10:19 UTC (permalink / raw)
To: linux-kernel
Cc: gregkh, davem, yoshfuji, dsahern, kuba, netdev, florian.fainelli,
ajay.kaher, vasavi.sirnapalli, tapas.kundu, ashwin.kamat,
Eric Dumazet, Sasha Levin
From: Eric Dumazet <edumazet@google.com>
[Upstream commit d289ab65b89c1d4d88417cb6c03e923f21f95fae]
disable_ipv6 is read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.
v2: do not preload net before rtnl_trylock() in
addrconf_disable_ipv6() (Jiri)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 4db783d68b9b ("ipv6: prevent NULL dereference in ip6_output()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[Ashwin: Regenerated the Patch for v5.15]
Signed-off-by: Ashwin Dayanand Kamat <ashwin.kamat@broadcom.com>
---
net/ipv6/addrconf.c | 9 +++++----
net/ipv6/ip6_input.c | 2 +-
net/ipv6/ip6_output.c | 2 +-
3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index a17e1d744b2d..ba22470b7476 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4131,7 +4131,7 @@ static void addrconf_dad_work(struct work_struct *w)
if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
ipv6_addr_equal(&ifp->addr, &addr)) {
/* DAD failed for link-local based on MAC */
- idev->cnf.disable_ipv6 = 1;
+ WRITE_ONCE(idev->cnf.disable_ipv6, 1);
pr_info("%s: IPv6 being disabled!\n",
ifp->idev->dev->name);
@@ -6277,7 +6277,8 @@ static void addrconf_disable_change(struct net *net, __s32 newf)
idev = __in6_dev_get(dev);
if (idev) {
int changed = (!idev->cnf.disable_ipv6) ^ (!newf);
- idev->cnf.disable_ipv6 = newf;
+
+ WRITE_ONCE(idev->cnf.disable_ipv6, newf);
if (changed)
dev_disable_change(idev);
}
@@ -6294,7 +6295,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
net = (struct net *)table->extra2;
old = *p;
- *p = newf;
+ WRITE_ONCE(*p, newf);
if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
rtnl_unlock();
@@ -6302,7 +6303,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
}
if (p == &net->ipv6.devconf_all->disable_ipv6) {
- net->ipv6.devconf_dflt->disable_ipv6 = newf;
+ WRITE_ONCE(net->ipv6.devconf_dflt->disable_ipv6, newf);
addrconf_disable_change(net, newf);
} else if ((!newf) ^ (!old))
dev_disable_change((struct inet6_dev *)table->extra1);
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 32071529bfd9..c1c29432367c 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -164,7 +164,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
__IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_IN, skb->len);
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
- !idev || unlikely(idev->cnf.disable_ipv6)) {
+ !idev || unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
goto drop;
}
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 7205473ba28d..770ee7ffb0d5 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -221,7 +221,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
- if (unlikely(idev->cnf.disable_ipv6)) {
+ if (unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
return 0;
--
2.45.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v5.15 2/2] net/ipv6: prevent NULL dereference in ip6_output()
2024-07-09 10:19 [PATCH v5.15 0/2] Fix for CVE-2024-36901 Ashwin Kamat
2024-07-09 10:19 ` [PATCH v5.15 1/2] net/ipv6: annotate data-races around cnf.disable_ipv6 Ashwin Kamat
@ 2024-07-09 10:19 ` Ashwin Kamat
2024-07-12 21:19 ` [PATCH v5.15 0/2] Fix for CVE-2024-36901 Florian Fainelli
2 siblings, 0 replies; 4+ messages in thread
From: Ashwin Kamat @ 2024-07-09 10:19 UTC (permalink / raw)
To: linux-kernel
Cc: gregkh, davem, yoshfuji, dsahern, kuba, netdev, florian.fainelli,
ajay.kaher, vasavi.sirnapalli, tapas.kundu, ashwin.kamat,
Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
[Upstream commit 4db783d68b9b39a411a96096c10828ff5dfada7a]
According to syzbot, there is a chance that ip6_dst_idev()
returns NULL in ip6_output(). Most places in IPv6 stack
deal with a NULL idev just fine, but not here.
syzbot reported:
general protection fault, probably for non-canonical address 0xdffffc00000000bc: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000005e0-0x00000000000005e7]
CPU: 0 PID: 9775 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00157-g6a30653b604a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:ip6_output+0x231/0x3f0 net/ipv6/ip6_output.c:237
Code: 3c 1e 00 49 89 df 74 08 4c 89 ef e8 19 58 db f7 48 8b 44 24 20 49 89 45 00 49 89 c5 48 8d 9d e0 05 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 4c 8b 74 24 28 0f 85 61 01 00 00 8b 1b 31 ff
RSP: 0018:ffffc9000927f0d8 EFLAGS: 00010202
RAX: 00000000000000bc RBX: 00000000000005e0 RCX: 0000000000040000
RDX: ffffc900131f9000 RSI: 0000000000004f47 RDI: 0000000000004f48
RBP: 0000000000000000 R08: ffffffff8a1f0b9a R09: 1ffffffff1f51fad
R10: dffffc0000000000 R11: fffffbfff1f51fae R12: ffff8880293ec8c0
R13: ffff88805d7fc000 R14: 1ffff1100527d91a R15: dffffc0000000000
FS: 00007f135c6856c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000064096000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
NF_HOOK include/linux/netfilter.h:314 [inline]
ip6_xmit+0xefe/0x17f0 net/ipv6/ip6_output.c:358
sctp_v6_xmit+0x9f2/0x13f0 net/sctp/ipv6.c:248
sctp_packet_transmit+0x26ad/0x2ca0 net/sctp/output.c:653
sctp_packet_singleton+0x22c/0x320 net/sctp/outqueue.c:783
sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline]
sctp_outq_flush+0x6d5/0x3e20 net/sctp/outqueue.c:1212
sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]
sctp_do_sm+0x59cc/0x60c0 net/sctp/sm_sideeffect.c:1169
sctp_primitive_ASSOCIATE+0x95/0xc0 net/sctp/primitive.c:73
__sctp_connect+0x9cd/0xe30 net/sctp/socket.c:1234
sctp_connect net/sctp/socket.c:4819 [inline]
sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
__sys_connect_file net/socket.c:2048 [inline]
__sys_connect+0x2df/0x310 net/socket.c:2065
__do_sys_connect net/socket.c:2075 [inline]
__se_sys_connect net/socket.c:2072 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2072
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: 778d80be5269 ("ipv6: Add disable_ipv6 sysctl to disable IPv6 operaion on specific interface.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Link: https://lore.kernel.org/r/20240507161842.773961-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[Ashwin: Regenerated the Patch for v5.15]
Signed-off-by: Ashwin Dayanand Kamat <ashwin.kamat@broadcom.com>
---
net/ipv6/ip6_output.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 770ee7ffb0d5..ce37c8345579 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -221,7 +221,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
- if (unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
+ if (unlikely(!idev || READ_ONCE(idev->cnf.disable_ipv6))) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
return 0;
--
2.45.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v5.15 0/2] Fix for CVE-2024-36901
2024-07-09 10:19 [PATCH v5.15 0/2] Fix for CVE-2024-36901 Ashwin Kamat
2024-07-09 10:19 ` [PATCH v5.15 1/2] net/ipv6: annotate data-races around cnf.disable_ipv6 Ashwin Kamat
2024-07-09 10:19 ` [PATCH v5.15 2/2] net/ipv6: prevent NULL dereference in ip6_output() Ashwin Kamat
@ 2024-07-12 21:19 ` Florian Fainelli
2 siblings, 0 replies; 4+ messages in thread
From: Florian Fainelli @ 2024-07-12 21:19 UTC (permalink / raw)
To: Ashwin Kamat, linux-kernel
Cc: gregkh, davem, yoshfuji, dsahern, kuba, netdev, ajay.kaher,
vasavi.sirnapalli, tapas.kundu
[-- Attachment #1: Type: text/plain, Size: 688 bytes --]
On 7/9/24 03:19, Ashwin Kamat wrote:
> From: Ashwin Dayanand Kamat <ashwin.kamat@broadcom.com>
>
> net/ipv6: annotate data-races around cnf.disable_ipv6
> disable_ipv6 is read locklessly, add appropriate READ_ONCE() and WRITE_ONCE() annotations.
>
> net/ipv6: prevent NULL dereference in ip6_output()
> Fix for CVE-2024-36901
LGTM!
>
> Ashwin Dayanand Kamat (2):
> net/ipv6: annotate data-races around cnf.disable_ipv6
> net/ipv6: prevent NULL dereference in ip6_output()
>
> net/ipv6/addrconf.c | 9 +++++----
> net/ipv6/ip6_input.c | 2 +-
> net/ipv6/ip6_output.c | 2 +-
> 3 files changed, 7 insertions(+), 6 deletions(-)
>
--
Florian
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^ permalink raw reply [flat|nested] 4+ messages in thread