6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
[ Upstream commit 7e4196935069947d8b70b09c1660b67b067e75cb ]
We observed a null-ptr-deref in fou_gro_receive() while shutting down
a host. [0]
The NULL pointer is sk->sk_user_data, and the offset 8 is of protocol
in struct fou.
When fou_release() is called due to netns dismantle or explicit tunnel
teardown, udp_tunnel_sock_release() sets NULL to sk->sk_user_data.
Then, the tunnel socket is destroyed after a single RCU grace period.
So, in-flight udp4_gro_receive() could find the socket and execute the
FOU GRO handler, where sk->sk_user_data could be NULL.
Let's use rcu_dereference_sk_user_data() in fou_from_sock() and add NULL
checks in FOU GRO handlers.
[0]:
BUG: kernel NULL pointer dereference, address: 0000000000000008
PF: supervisor read access in kernel mode
PF: error_code(0x0000) - not-present page
PGD 80000001032f4067 P4D 80000001032f4067 PUD 103240067 PMD 0
SMP PTI
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.216-204.855.amzn2.x86_64 #1
Hardware name: Amazon EC2 c5.large/, BIOS 1.0 10/16/2017
RIP: 0010:fou_gro_receive (net/ipv4/fou.c:233) [fou]
Code: 41 5f c3 cc cc cc cc e8 e7 2e 69 f4 0f 1f 80 00 00 00 00 0f 1f 44 00 00 49 89 f8 41 54 48 89 f7 48 89 d6 49 8b 80 88 02 00 00 <0f> b6 48 08 0f b7 42 4a 66 25 fd fd 80 cc 02 66 89 42 4a 0f b6 42
RSP: 0018:ffffa330c0003d08 EFLAGS: 00010297
RAX: 0000000000000000 RBX: ffff93d9e3a6b900 RCX: 0000000000000010
RDX: ffff93d9e3a6b900 RSI: ffff93d9e3a6b900 RDI: ffff93dac2e24d08
RBP: ffff93d9e3a6b900 R08: ffff93dacbce6400 R09: 0000000000000002
R10: 0000000000000000 R11: ffffffffb5f369b0 R12: ffff93dacbce6400
R13: ffff93dac2e24d08 R14: 0000000000000000 R15: ffffffffb4edd1c0
FS: 0000000000000000(0000) GS:ffff93daee800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000102140001 CR4: 00000000007706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259)
? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420)
? no_context (arch/x86/mm/fault.c:752)
? exc_page_fault (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 arch/x86/mm/fault.c:1435 arch/x86/mm/fault.c:1483)
? asm_exc_page_fault (arch/x86/include/asm/idtentry.h:571)
? fou_gro_receive (net/ipv4/fou.c:233) [fou]
udp_gro_receive (include/linux/netdevice.h:2552 net/ipv4/udp_offload.c:559)
udp4_gro_receive (net/ipv4/udp_offload.c:604)
inet_gro_receive (net/ipv4/af_inet.c:1549 (discriminator 7))
dev_gro_receive (net/core/dev.c:6035 (discriminator 4))
napi_gro_receive (net/core/dev.c:6170)
ena_clean_rx_irq (drivers/amazon/net/ena/ena_netdev.c:1558) [ena]
ena_io_poll (drivers/amazon/net/ena/ena_netdev.c:1742) [ena]
napi_poll (net/core/dev.c:6847)
net_rx_action (net/core/dev.c:6917)
__do_softirq (arch/x86/include/asm/jump_label.h:25 include/linux/jump_label.h:200 include/trace/events/irq.h:142 kernel/softirq.c:299)
asm_call_irq_on_stack (arch/x86/entry/entry_64.S:809)
</IRQ>
do_softirq_own_stack (arch/x86/include/asm/irq_stack.h:27 arch/x86/include/asm/irq_stack.h:77 arch/x86/kernel/irq_64.c:77)
irq_exit_rcu (kernel/softirq.c:393 kernel/softirq.c:423 kernel/softirq.c:435)
common_interrupt (arch/x86/kernel/irq.c:239)
asm_common_interrupt (arch/x86/include/asm/idtentry.h:626)
RIP: 0010:acpi_idle_do_entry (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 drivers/acpi/processor_idle.c:114 drivers/acpi/processor_idle.c:575)
Code: 8b 15 d1 3c c4 02 ed c3 cc cc cc cc 65 48 8b 04 25 40 ef 01 00 48 8b 00 a8 08 75 eb 0f 1f 44 00 00 0f 00 2d d5 09 55 00 fb f4 <fa> c3 cc cc cc cc e9 be fc ff ff 66 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffffffb5603e58 EFLAGS: 00000246
RAX: 0000000000004000 RBX: ffff93dac0929c00 RCX: ffff93daee833900
RDX: ffff93daee800000 RSI: ffff93daee87dc00 RDI: ffff93daee87dc64
RBP: 0000000000000001 R08: ffffffffb5e7b6c0 R09: 0000000000000044
R10: ffff93daee831b04 R11: 00000000000001cd R12: 0000000000000001
R13: ffffffffb5e7b740 R14: 0000000000000001 R15: 0000000000000000
? sched_clock_cpu (kernel/sched/clock.c:371)
acpi_idle_enter (drivers/acpi/processor_idle.c:712 (discriminator 3))
cpuidle_enter_state (drivers/cpuidle/cpuidle.c:237)
cpuidle_enter (drivers/cpuidle/cpuidle.c:353)
cpuidle_idle_call (kernel/sched/idle.c:158 kernel/sched/idle.c:239)
do_idle (kernel/sched/idle.c:302)
cpu_startup_entry (kernel/sched/idle.c:395 (discriminator 1))
start_kernel (init/main.c:1048)
secondary_startup_64_no_verify (arch/x86/kernel/head_64.S:310)
Modules linked in: udp_diag tcp_diag inet_diag nft_nat ipip tunnel4 dummy fou ip_tunnel nft_masq nft_chain_nat nf_nat wireguard nft_ct curve25519_x86_64 libcurve25519_generic nf_conntrack libchacha20poly1305 nf_defrag_ipv6 nf_defrag_ipv4 nft_objref chacha_x86_64 nft_counter nf_tables nfnetlink poly1305_x86_64 ip6_udp_tunnel udp_tunnel libchacha crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd cryptd glue_helper mousedev psmouse button ena ptp pps_core crc32c_intel
CR2: 0000000000000008
Fixes: d92283e338f6 ("fou: change to use UDP socket GRO")
Reported-by: Alphonse Kurian <alkurian@xxxxxxxxxx>
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://patch.msgid.link/20240902173927.62706-1-kuniyu@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/fou.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 358bff068eef..7bcc933103e2 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -48,7 +48,7 @@ struct fou_net {
static inline struct fou *fou_from_sock(struct sock *sk)
{
- return sk->sk_user_data;
+ return rcu_dereference_sk_user_data(sk);
}
static int fou_recv_pull(struct sk_buff *skb, struct fou *fou, size_t len)
@@ -231,9 +231,15 @@ static struct sk_buff *fou_gro_receive(struct sock *sk,
struct sk_buff *skb)
{
const struct net_offload __rcu **offloads;
- u8 proto = fou_from_sock(sk)->protocol;
+ struct fou *fou = fou_from_sock(sk);
const struct net_offload *ops;
struct sk_buff *pp = NULL;
+ u8 proto;
+
+ if (!fou)
+ goto out;
+
+ proto = fou->protocol;
/* We can clear the encap_mark for FOU as we are essentially doing
* one of two possible things. We are either adding an L4 tunnel
@@ -261,14 +267,24 @@ static int fou_gro_complete(struct sock *sk, struct sk_buff *skb,
int nhoff)
{
const struct net_offload __rcu **offloads;
- u8 proto = fou_from_sock(sk)->protocol;
+ struct fou *fou = fou_from_sock(sk);
const struct net_offload *ops;
- int err = -ENOSYS;
+ u8 proto;
+ int err;
+
+ if (!fou) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ proto = fou->protocol;
offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
ops = rcu_dereference(offloads[proto]);
- if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+ if (WARN_ON(!ops || !ops->callbacks.gro_complete)) {
+ err = -ENOSYS;
goto out;
+ }
err = ops->callbacks.gro_complete(skb, nhoff);
@@ -318,6 +334,9 @@ static struct sk_buff *gue_gro_receive(struct sock *sk,
struct gro_remcsum grc;
u8 proto;
+ if (!fou)
+ goto out;
+
skb_gro_remcsum_init(&grc);
off = skb_gro_offset(skb);
--
2.43.0
