6.6-stable review patch. If anyone has any objections, please let me know.
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From: Alexandre Cassen acassen@corp.free.fr
[ Upstream commit 600258d555f0710b9c47fb78d2d80a4aecd608cc ]
Packets handled by hardware have added secpath as a way to inform XFRM core code that this path was already handled. That secpath is not needed at all after policy is checked and it is removed later in the stack.
However, in the case of IP forwarding is enabled (/proc/sys/net/ipv4/ip_forward), that secpath is not removed and packets which already were handled are reentered to the driver TX path with xfrm_offload set.
The following kernel panic is observed in mlx5 in such case:
mlx5_core 0000:04:00.0 enp4s0f0np0: Link up mlx5_core 0000:04:00.1 enp4s0f1np1: Link up Initializing XFRM netlink socket IPsec XFRM device driver BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 0 P4D 0 Oops: Oops: 0010 [#1] PREEMPT SMP CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc1-alex #3 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffb87380003800 EFLAGS: 00010206 RAX: ffff8df004e02600 RBX: ffffb873800038d8 RCX: 00000000ffff98cf RDX: ffff8df00733e108 RSI: ffff8df00521fb80 RDI: ffff8df001661f00 RBP: ffffb87380003850 R08: ffff8df013980000 R09: 0000000000000010 R10: 0000000000000002 R11: 0000000000000002 R12: ffff8df001661f00 R13: ffff8df00521fb80 R14: ffff8df00733e108 R15: ffff8df011faf04e FS: 0000000000000000(0000) GS:ffff8df46b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000106384000 CR4: 0000000000350ef0 Call Trace: <IRQ> ? show_regs+0x63/0x70 ? __die_body+0x20/0x60 ? __die+0x2b/0x40 ? page_fault_oops+0x15c/0x550 ? do_user_addr_fault+0x3ed/0x870 ? exc_page_fault+0x7f/0x190 ? asm_exc_page_fault+0x27/0x30 mlx5e_ipsec_handle_tx_skb+0xe7/0x2f0 [mlx5_core] mlx5e_xmit+0x58e/0x1980 [mlx5_core] ? __fib_lookup+0x6a/0xb0 dev_hard_start_xmit+0x82/0x1d0 sch_direct_xmit+0xfe/0x390 __dev_queue_xmit+0x6d8/0xee0 ? __fib_lookup+0x6a/0xb0 ? internal_add_timer+0x48/0x70 ? mod_timer+0xe2/0x2b0 neigh_resolve_output+0x115/0x1b0 __neigh_update+0x26a/0xc50 neigh_update+0x14/0x20 arp_process+0x2cb/0x8e0 ? __napi_build_skb+0x5e/0x70 arp_rcv+0x11e/0x1c0 ? dev_gro_receive+0x574/0x820 __netif_receive_skb_list_core+0x1cf/0x1f0 netif_receive_skb_list_internal+0x183/0x2a0 napi_complete_done+0x76/0x1c0 mlx5e_napi_poll+0x234/0x7a0 [mlx5_core] __napi_poll+0x2d/0x1f0 net_rx_action+0x1a6/0x370 ? atomic_notifier_call_chain+0x3b/0x50 ? irq_int_handler+0x15/0x20 [mlx5_core] handle_softirqs+0xb9/0x2f0 ? handle_irq_event+0x44/0x60 irq_exit_rcu+0xdb/0x100 common_interrupt+0x98/0xc0 </IRQ> <TASK> asm_common_interrupt+0x27/0x40 RIP: 0010:pv_native_safe_halt+0xb/0x10 Code: 09 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 22 0f 1f 84 00 00 00 00 00 90 eb 07 0f 00 2d 7f e9 36 00 fb 40 00 83 ff 07 77 21 89 ff ff 24 fd 88 3d a1 bd 0f 21 f8 RSP: 0018:ffffffffbe603de8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000f92f46680 RDX: 0000000000000037 RSI: 00000000ffffffff RDI: 00000000000518d4 RBP: ffffffffbe603df0 R08: 000000cd42e4dffb R09: ffffffffbe603d70 R10: 0000004d80d62680 R11: 0000000000000001 R12: ffffffffbe60bf40 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffbe60aff8 ? default_idle+0x9/0x20 arch_cpu_idle+0x9/0x10 default_idle_call+0x29/0xf0 do_idle+0x1f2/0x240 cpu_startup_entry+0x2c/0x30 rest_init+0xe7/0x100 start_kernel+0x76b/0xb90 x86_64_start_reservations+0x18/0x30 x86_64_start_kernel+0xc0/0x110 ? setup_ghcb+0xe/0x130 common_startup_64+0x13e/0x141 </TASK> Modules linked in: esp4_offload esp4 xfrm_interface xfrm6_tunnel tunnel4 tunnel6 xfrm_user xfrm_algo binfmt_misc intel_rapl_msr intel_rapl_common kvm_amd ccp kvm input_leds serio_raw qemu_fw_cfg sch_fq_codel dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua efi_pstore ip_tables x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx libcrc32c raid1 raid0 mlx5_core crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 sha1_ssse3 ahci mlxfw i2c_i801 libahci i2c_mux i2c_smbus psample virtio_rng pci_hyperv_intf aesni_intel crypto_simd cryptd CR2: 0000000000000000 ---[ end trace 0000000000000000 ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffb87380003800 EFLAGS: 00010206 RAX: ffff8df004e02600 RBX: ffffb873800038d8 RCX: 00000000ffff98cf RDX: ffff8df00733e108 RSI: ffff8df00521fb80 RDI: ffff8df001661f00 RBP: ffffb87380003850 R08: ffff8df013980000 R09: 0000000000000010 R10: 0000000000000002 R11: 0000000000000002 R12: ffff8df001661f00 R13: ffff8df00521fb80 R14: ffff8df00733e108 R15: ffff8df011faf04e FS: 0000000000000000(0000) GS:ffff8df46b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000106384000 CR4: 0000000000350ef0 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: 0x3b800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Fixes: 5958372ddf62 ("xfrm: add RX datapath protection for IPsec packet offload mode") Signed-off-by: Alexandre Cassen acassen@corp.free.fr Signed-off-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/xfrm.h | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 93a9866ee481f..b33d27e42cff3 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -1181,9 +1181,19 @@ static inline int __xfrm_policy_check2(struct sock *sk, int dir,
if (xo) { x = xfrm_input_state(skb); - if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) - return (xo->flags & CRYPTO_DONE) && - (xo->status & CRYPTO_SUCCESS); + if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) { + bool check = (xo->flags & CRYPTO_DONE) && + (xo->status & CRYPTO_SUCCESS); + + /* The packets here are plain ones and secpath was + * needed to indicate that hardware already handled + * them and there is no need to do nothing in addition. + * + * Consume secpath which was set by drivers. + */ + secpath_reset(skb); + return check; + } }
return __xfrm_check_nopolicy(net, skb, dir) ||